1.2 GHz Clock Distribution IC, PLL Core,
Dividers, Delay Adjust, Five Outputs
AD9511
Rev. A
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FEATURES
Low phase noise phase-locked loop core
Reference input frequencies to 250 MHz
Programmable dual-modulus prescaler
Programmable charge pump (CP) current
Separate CP supply (VCPS) extends tuning range
Two 1.6 GHz, differential clock inputs
5 programmable dividers, 1 to 32, all integers
Phase select for output-to-output coarse delay adjust
3 independent 1.2 GHz LVPECL outputs
Additive output jitter 225 fs rms
2 independent 800 MHz/250 MHz LVDS/CMOS clock outputs
Additive output jitter 275 fs rms
Fine delay adjust on 1 LVDS/CMOS output
Serial control port
Space-saving 48-lead LFCSP
APPLICATIONS
Low jitter, low phase noise clock distribution
Clocking high speed ADCs, DACs, DDSs, DDCs, DUCs, MxFEs
High performance wireless transceivers
High performance instrumentation
Broadband infrastructure
FUNCTIONAL BLOCK DIAGRAM
05286-001
R DIVIDER
N DIVIDER
PHASE
FREQUENCY
DETECTOR CHARGE
PUMP
PLL
SETTINGS
CLK2
STATUS
CLK2B
PROGRAMMABLE
DIVIDERS AND
PHASE ADJUST OUT0
OUT0B
LVPECL
/1, /2, /3... /31, /32
OUT1
OUT1B
LVPECL
/1, /2, /3... /31, /32
OUT2
OUT2B
LVPECL
/1, /2, /3... /31, /32
OUT3
OUT3B
LVDS/CMOS
/1, /2, /3... /31, /32
OUT4
OUT4B
LVDS/CMOS
/1, /2, /3... /31, /32
DELAY
ADJUST
Δ
T
CLK1
CLK1B
REFIN
REFINB
FUNCTION
SCLK
SDIO
SDO
CSB
SERIAL
CONTROL
PORT
CP
CPRSE
T
DISTRIBUTION
REF
SYNCB,
RESETB
PDB
RSE
T
AD9511
GND
V
S
V
CP
PLL
REF
Figure 1.
GENERAL DESCRIPTION
The AD9511 provides a multi-output clock distribution
function along with an on-chip PLL core. The design
emphasizes low jitter and phase noise to maximize data
converter performance. Other applications with demanding
phase noise and jitter requirements also benefit from this part.
The PLL section consists of a programmable reference divider
(R); a low noise phase frequency detector (PFD); a precision
charge pump (CP); and a programmable feedback divider (N).
By connecting an external VCXO or VCO to the CLK2/CLK2B
pins, frequencies up to 1.6 GHz may be synchronized to the
input reference.
There are five independent clock outputs. Three outputs are
LVPECL (1.2 GHz), and two are selectable as either LVDS
(800 MHz) or CMOS (250 MHz) levels.
Each output has a programmable divider that may be bypassed
or set to divide by any integer up to 32. The phase of one clock
output relative to another clock output may be varied by means
of a divider phase select function that serves as a coarse timing
adjustment. One of the LVDS/CMOS outputs features a
programmable delay element with full-scale ranges up to 10 ns
of delay. This fine tuning delay block has 5-bit resolution, giving
32 possible delays from which to choose for each full-scale
setting.
The AD9511 is ideally suited for data converter clocking
applications where maximum converter performance is
achieved by encode signals with subpicosecond jitter.
The AD9511 is available in a 48-lead LFCSP and can be
operated from a single 3.3 V supply. An external VCO, which
requires an extended voltage range, can be accommodated by
connecting the charge pump supply (VCP) to 5.5 V. The
temperature range is −40°C to +85°C.
AD9511
Rev. A | Page 2 of 60
TABLE OF CONTENTS
Specifications..................................................................................... 4
PLL Characteristics ...................................................................... 4
Clock Inputs .................................................................................. 5
Clock Outputs............................................................................... 6
Timing Characteristics ................................................................ 7
Clock Output Phase Noise .......................................................... 9
Clock Output Additive Time Jitter........................................... 12
PLL and Distribution Phase Noise and Spurious................... 14
Serial Control Port ..................................................................... 15
FUNCTION Pin ......................................................................... 15
STATUS Pin ................................................................................ 16
Power............................................................................................ 16
Timing Diagrams............................................................................ 17
Absolute Maximum Ratings.......................................................... 18
Thermal Characteristics ............................................................ 18
ESD Caution................................................................................ 18
Pin Configuration and Function Descriptions........................... 19
Ter mi no log y .................................................................................... 21
Typical Performance Characteristics ........................................... 22
Typical Modes of Operation.......................................................... 26
PLL with External VCXO/VCO Followed by Clock
Distribution................................................................................. 26
Clock Distribution Only............................................................ 26
PLL with External VCO and Band-Pass Filter Followed by
Clock Distribution...................................................................... 27
Functional Description .................................................................. 29
Overall.......................................................................................... 29
PLL Section ................................................................................. 29
PLL Reference Input—REFIN.............................................. 29
VCO/VCXO Clock Input—CLK2........................................ 29
PLL Reference Divider—R.................................................... 29
VCO/VCXO Feedback Divider—N (P, A, B) ..................... 29
A and B Counters................................................................... 30
Determining Values for P, A, B, and R ................................ 30
Phase Frequency Detector (PFD) and Charge Pump ....... 31
Antibacklash Pulse................................................................. 31
STATUS Pin ............................................................................ 31
PLL Digital Lock Detect........................................................ 31
PLL Analog Lock Detect ....................................................... 32
Loss of Reference.................................................................... 32
FUNCTION Pin ......................................................................... 32
RESETB: 58h<6:5> = 00b (Default)..................................... 32
SYNCB: 58h<6:5> = 01b ....................................................... 32
PDB: 58h<6:5> = 11b ............................................................ 33
Distribution Section................................................................... 33
CLK1 and CLK2 Clock Inputs.................................................. 33
Dividers........................................................................................ 33
Setting the Divide Ratio ........................................................ 33
Setting the Duty Cycle........................................................... 33
Divider Phase Offset.............................................................. 37
Delay Block ................................................................................. 38
Calculating the Delay ............................................................ 38
Outputs ........................................................................................ 38
Power-Down Modes .................................................................. 39
Chip Power-Down or Sleep Mode—PDB........................... 39
PLL Power-Down................................................................... 39
Distribution Power-Down .................................................... 39
Individual Clock Output Power-Down............................... 39
Individual Circuit Block Power-Down................................ 39
Reset Modes ................................................................................ 40
Power-On Reset—Start-Up Conditions when VS
is Applied................................................................................. 40
Asynchronous Reset via the FUNCTION Pin ................... 40
Soft Reset via the Serial Port................................................. 40
AD9511
Rev. A | Page 3 of 60
Single-Chip Synchronization.....................................................40
SYNCB—Hardware SYNC ....................................................40
Soft SYNC—Register 58h<2> ...............................................40
Multichip Synchronization ........................................................40
Serial Control Port ..........................................................................41
Serial Control Port Pin Descriptions........................................41
General Operation of Serial Control Port ...............................41
Framing a Communication Cycle with CSB .......................41
Communication Cycle—Instruction Plus Data..................41
Write .........................................................................................41
Read ..........................................................................................42
The Instruction Word (16 Bits).................................................42
MSB/LSB First Transfers ............................................................42
Register Map and Description.......................................................45
Summary Table............................................................................45
Register Map Description ..........................................................47
Power Supply ...................................................................................54
Power Management ....................................................................54
Applications .....................................................................................55
Using the AD9511 Outputs for ADC Clock Applications ....55
CMOS Clock Distribution.........................................................55
LVPECL Clock Distribution......................................................56
LVDS Clock Distribution...........................................................56
Power and Grounding Considerations and Power Supply
Rejection.......................................................................................56
Outline Dimensions........................................................................57
Ordering Guide ...........................................................................57
REVISION HISTORY
6/05—Rev. 0 to Rev. A
Changes to Features ..........................................................................1
Changes to General Description .....................................................1
Changes to Table 1 and Table 2 .......................................................5
Changes to Table 4 ............................................................................7
Changes to Table 5 ............................................................................9
Changes to Table 6 ..........................................................................14
Changes to Table 8 and Table 9 .....................................................15
Changes to Table 11 ........................................................................16
Changes to Table 13 ........................................................................20
Changes to Figure 19 to Figure 23 ................................................24
Changes to Figure 30 and Figure 31 .............................................26
Changes to Figure 32 ......................................................................27
Changes to Figure 33 ......................................................................28
Changes to VCO/VCXO Clock Input—CLK2 Section..............29
Changes to PLL Reference Divider—P Section...........................29
Changes to A and B Counters Section .........................................30
Changes to PLL Digital Lock Detect Section ..............................31
Changes to PLL Analog Lock Detect Section..............................32
Changes to Loss of Reference Section ..........................................32
Changes to FUNCTION Pin Section ...........................................32
Changes to RESETB: 58h<6:5> = 00b (Default) Section ...........32
Changes to SYNCB: 58h<6:5> = 01b Section..............................32
Changes to CLK1 and CLK2 Clock Inputs Section....................33
Changes to Divider Phase Offset Section ....................................37
Changes to Individual Clock Output Power-Down Section.....39
Changes to Individual Circuit Block Power-Down Section......39
Changes to Soft Reset via the Serial Port Section.......................40
Changes to Multichip Synchronization Section..........................40
Changes to Serial Control Port Section .......................................41
Changes to Serial Control Port Pin Descriptions Section .........41
Changes to General Operation of Serial
Control Port Section.......................................................................41
Added Framing a Communication Cycle with CSB Section ....41
Added Communication Cycle—Instruction Plus
Data Section.....................................................................................41
Changes to Write Section...............................................................41
Changes to Read Section................................................................42
Changes to Instruction Word (16 Bits) Section ..........................42
Changes to Table 20 ........................................................................42
Changes to MSB/LSB First Transfers Section..............................42
Added Figure 52; Renumbered Sequentially...............................44
Changes to Table 23 ........................................................................45
Changes to Table 24 ........................................................................47
Changes to Power Supply...............................................................54
4/05—Revision 0: Initial Version
AD9511
Rev. A | Page 4 of 60
SPECIFICATIONS
Typical (typ) is given for VS = 3.3 V ± 5%; VS ≤ VCPS ≤ 5.5 V, TA = 25°C, RSET = 4.12 kΩ, CPRSET = 5.1 kΩ, unless otherwise noted.
Minimum (min) and maximum (max) values are given over full VS and TA (−40°C to +85°C) variation.
PLL CHARACTERISTICS
Table 1.
Parameter Min Typ Max Unit Test Conditions/Comments
REFERENCE INPUTS (REFIN)
Input Frequency 0 250 MHz
Input Sensitivity 150 mV p-p
Self-Bias Voltage, REFIN 1.45 1.60 1.75 V Self-bias voltage of REFIN1.
Self-Bias Voltage, REFINB 1.40 1.50 1.60 V Self-bias voltage of REFINB1.
Input Resistance, REFIN 4.0 4.9 5.8 kΩ Self-biased1.
Input Resistance, REFINB 4.5 5.4 6.3 kΩ Self-biased1.
Input Capacitance 2 pF
PHASE/FREQUENCY DETECTOR (PFD)
PFD Input Frequency 100 MHz Antibacklash pulse width 0Dh<1:0> = 00b.
PFD Input Frequency 100 MHz Antibacklash pulse width 0Dh<1:0> = 01b.
PFD Input Frequency 45 MHz Antibacklash pulse width 0Dh<1:0> = 10b.
Antibacklash Pulse Width 1.3 ns 0Dh<1:0> = 00b. (This is the default setting.)
Antibacklash Pulse Width 2.9 ns 0Dh<1:0> = 01b.
Antibacklash Pulse Width 6.0 ns 0Dh<1:0> = 10b.
CHARGE PUMP (CP)
ICP Sink/Source Programmable.
High Value 4.8 mA
Low Value 0.60 mA
With CPRSET = 5.1 kΩ.
Absolute Accuracy 2.5 % VCP = VCPS/2.
CPRSET Range 2.7/10 kΩ
ICP Three-State Leakage 1 nA
Sink-and-Source Current Matching 2 % 0.5 < VCP < VCPS − 0.5 V.
ICP vs. VCP 1.5 % 0.5 < VCP < VCPS − 0.5 V.
ICP vs. Temperature 2 % VCP = VCPS/2 V.
RF CHARACTERISTICS (CLK2)2
Input Frequency 1.6 GHz Frequencies > 1200 MHz (LVPECL) or
800 MHz (LVDS) require a minimum
divide-by-2 (see the Distribution Section).
Input Sensitivity 150 mV p-p
Input Common-Mode Voltage, VCM 1.5 1.6 1.7 V Self-biased; enables ac coupling.
Input Common-Mode Range, VCMR 1.3 1.8 V With 200 mV p-p signal applied.
Input Sensitivity, Single-Ended 150 mV p-p CLK2 ac-coupled; CLK2B capacitively
bypassed to RF ground.
Input Resistance 4.0 4.8 5.6 kΩ Self-biased.
Input Capacitance 2 pF
CLK2 VS. REFIN DELAY 500 ps Difference at PFD.
PRESCALER (PART OF N DIVIDER) See the VCO/VCXO Feedback Divider—N (P, A, B)
section.
Prescaler Input Frequency
P = 2 DM (2/3) 600 MHz
P = 4 DM (4/5) 1000 MHz
P = 8 DM (8/9) 1600 MHz
P = 16 DM (16/17) 1600 MHz
P = 32 DM (32/33) 1600 MHz
CLK2 Input Frequency for PLL 300 MHz A, B counter input frequency.
AD9511
Rev. A | Page 5 of 60
Parameter Min Typ Max Unit Test Conditions/Comments
NOISE CHARACTERISTICS
In-Band Noise of the Charge Pump/
Phase Frequency Detector (In-Band
Means Within the LBW of the PLL)
The synthesizer phase noise floor is
estimated by measuring the in-band
phase noise at the output of the VCO and
subtracting 20logN (where N is the
N divider value).
@ 50 kHz PFD Frequency −172 dBc/Hz
@ 2 MHz PFD Frequency −156 dBc/Hz
@ 10 MHz PFD Frequency −149 dBc/Hz
@ 50 MHz PFD Frequency −142 dBc/Hz
PLL Figure of Merit −218 +
10 × log (fPFD)
dBc/Hz
Approximation of the PFD/CP phase noise
floor (in the flat region) inside the PLL loop
bandwidth. When running closed loop this
phase noise is gained up by 20 × log(N)3.
PLL DIGITAL LOCK DETECT WINDOW4 Signal available at STATUS pin
when selected by 08h<5:2>.
Required to Lock
(Coincidence of Edges)
Selected by Register ODh.
Low Range (ABP 1.3 ns, 2.9 ns Only) 3.5 ns <5> = 1b.
High Range (ABP 1.3 ns, 2.9 ns) 7.5 ns <5> = 0b.
High Range (ABP 6 ns) 3.5 ns <5> = 0b.
To Unlock After Lock (Hysteresis)4 Selected by Register 0Dh.
Low Range (ABP 1.3 ns, 2.9 ns Only) 7 ns <5> = 1b.
High Range (ABP 1.3 ns, 2.9 ns) 15 ns <5> = 0b.
High Range (ABP 6 ns) 11 ns <5> = 0b.
1 REFIN and REFINB self-bias points are offset slightly to avoid chatter on an open input condition.
2 CLK2 is electrically identical to CLK1; the distribution only input can be used as differential or single-ended input (see the Clock Inputs section).
3 Example: −218 + 10 × log(fPFD) + 20 × log(N) should give the values for the in-band noise at the VCO output.
4 For reliable operation of the digital lock detect, the period of the PFD frequency must be greater than the unlock-after-lock time.
CLOCK INPUTS
Table 2.
Parameter Min Typ Max Unit Test Conditions/Comments
CLOCK INPUTS (CLK1, CLK2)1
Input Frequency 0 1.6 GHz
Input Sensitivity 1502 mV p-p
Jitter performance can be improved with higher slew
rates (greater swing).
Input Level 23V p-p Larger swings turn on the protection diodes and can
degrade jitter performance.
Input Common-Mode Voltage, VCM 1.5 1.6 1.7 V Self-biased; enables ac coupling.
Input Common-Mode Range, VCMR 1.3 1.8 V With 200 mV p-p signal applied; dc-coupled.
Input Sensitivity, Single-Ended 150 mV p-p CLK2 ac-coupled; CLK2B ac bypassed to RF ground.
Input Resistance 4.0 4.8 5.6 kΩ Self-biased.
Input Capacitance 2 pF
1 CLK1 and CLK2 are electrically identical; each can be used as either differential or single-ended input.
2 With a 50 Ω termination, this is −12.5 dBm.
3 With a 50 Ω termination, this is +10 dBm.
AD9511
Rev. A | Page 6 of 60
CLOCK OUTPUTS
Table 3.
Parameter Min Typ Max Unit Test Conditions/Comments
LVPECL CLOCK OUTPUTS Termination = 50 Ω to VS − 2 V
OUT0, OUT1, OUT2; Differential Output level 3Dh (3Eh) (3Fh)<3:2> = 10b
Output Frequency 1200 MHz See Figure 21
Output High Voltage (VOH) VS − 1.22 VS − 0.98 VS − 0.93 V
Output Low Voltage (VOL) VS − 2.10 VS − 1.80 VS − 1.67 V
Output Differential Voltage (VOD) 660 810 965 mV
LVDS CLOCK OUTPUTS Termination = 100 Ω differential; default
OUT3, OUT4; Differential
Output level 40h (41h)<2:1> = 01b
3.5 mA termination current
Output Frequency 800 MHz See Figure 22
Differential Output Voltage (VOD) 250 360 450 mV
Delta VOD 25 mV
Output Offset Voltage (VOS) 1.125 1.23 1.375 V
Delta VOS 25 mV
Short-Circuit Current (ISA, ISB) 14 24 mA Output shorted to GND
CMOS CLOCK OUTPUTS
OUT3, OUT4
Single-ended measurements;
B outputs: inverted, termination open
Output Frequency 250 MHz With 5 pF load each output; see Figure 23
Output Voltage High (VOH) VS-0.1 V @ 1 mA load
Output Voltage Low (VOL) 0.1 V @ 1 mA load
AD9511
Rev. A | Page 7 of 60
TIMING CHARACTERISTICS
Table 4.
Parameter Min Typ Max Unit Test Conditions/Comments
LVPECL Termination = 50 Ω to VS − 2 V
Output level 3Dh (3Eh) (3Fh)<3:2> = 10b
Output Rise Time, tRP 130 180 ps 20% to 80%, measured differentially
Output Fall Time, tFP 130 180 ps 80% to 20%, measured differentially
PROPAGATION DELAY, tPECL, CLK-TO-LVPECL OUT1
Divide = Bypass 335 490 635 ps
Divide = 2 − 32 375 545 695 ps
Variation with Temperature 0.5 ps/°C
OUTPUT SKEW, LVPECL OUTPUTS
OUT1 to OUT0 on Same Part, tSKP270 100 140 ps
OUT1 to OUT2 on Same Part, tSKP215 45 80 ps
OUT0 to OUT2 on Same Part, tSKP245 65 90 Ps
All LVPECL OUT Across Multiple Parts, tSKP_AB3 275 ps
Same LVPECL OUT Across Multiple Parts, tSKP_AB3 130 ps
LVDS Termination = 100 Ω differential
Output level 40h (41h) <2:1> = 01b
3.5 mA termination current
Output Rise Time, tRL 200 350 ps 20% to 80%, measured differentially
Output Fall Time, tFL 210 350 ps 80% to 20%, measured differentially
PROPAGATION DELAY, tLVDS, CLK-TO-LVDS OUT1 Delay off on OUT4
OUT3 to OUT4
Divide = Bypass 0.99 1.33 1.59 ns
Divide = 2 − 32 1.04 1.38 1.64 ns
Variation with Temperature 0.9 ps/°C
OUTPUT SKEW, LVDS OUTPUTS Delay off on OUT4
OUT3 to OUT4 on Same Part, tSKV2−85 +270 ps
All LVDS OUTs Across Multiple Parts, tSKV_AB3 450 ps
Same LVDS OUT Across Multiple Parts, tSKV_AB3 325 ps
CMOS B outputs are inverted; termination = open
Output Rise Time, tRC 681 865 ps 20% to 80%; CLOAD = 3 pF
Output Fall Time, tFC 646 992 ps 80% to 20%; CLOAD = 3 pF
PROPAGATION DELAY, tCMOS, CLK-TO-CMOS OUT1 Delay off on OUT4
Divide = Bypass 1.02 1.39 1.71 ns
Divide = 2 − 32 1.07 1.44 1.76 ns
Variation with Temperature 1 ps/°C
OUTPUT SKEW, CMOS OUTPUTS Delay off on OUT4
OUT3 to OUT4 on Same Part, tSKC2−140 +145 +300
All CMOS OUT Across Multiple Parts, tSKC_AB3 650 ps
Same CMOS OUT Across Multiple Parts, tSKC_AB3 500 ps
LVPECL-TO-LVDS OUT Everything the same; different logic type
Output Skew, tSKP_V 0.74 0.92 1.14 ns LVPECL to LVDS on same part
LVPECL-TO-CMOS OUT Everything the same; different logic type
Output Skew, tSKP_C 0.88 1.14 1.43 ns LVPECL to CMOS on same part
LVDS-TO-CMOS OUT Everything the same; different logic type
Output Skew, tSKV_C 158 353 506 ps LVDS to CMOS on same part
AD9511
Rev. A | Page 8 of 60
Parameter Min Typ Max Unit Test Conditions/Comments
DELAY ADJUST OUT4; LVDS and CMOS
Shortest Delay Range4 35h <5:1> 11111b
Zero Scale 0.05 0.36 0.68 ns 36h <5:1> 00000b
Full Scale 0.72 1.12 1.51 ns 36h <5:1> 11111b
Linearity, DNL 0.5 LSB
Linearity, INL 0.8 LSB
Longest Delay Range4 35h <5:1> 00000b
Zero Scale 0.20 0.57 0.95 ns 36h <5:1> 00000b
Full Scale 9.0 10.2 11.6 ns 36h <5:1> 11111b
Linearity, DNL 0.3 LSB
Linearity, INL 0.6 LSB
Delay Variation with Temperature
Long Delay Range, 10 ns5
Zero Scale 0.35 ps/°C
Full Scale −0.14 ps/°C
Short Delay Range, 1 ns5
Zero Scale 0.51 ps/°C
Full Scale 0.67 ps/°C
1 The measurements are for CLK1. For CLK2, add approximately 25 ps.
2 This is the difference between any two similar delay paths within a single device operating at the same voltage and temperature.
3 This is the difference between any two similar delay paths across multiple devices operating at the same voltage and temperature.
4 Incremental delay; does not include propagation delay.
5 All delays between zero scale and full scale can be estimated by linear interpolation.
AD9511
Rev. A | Page 9 of 60
CLOCK OUTPUT PHASE NOISE
Table 5.
Parameter Min Typ Max Unit Test Conditions/Comments
CLK1-TO-LVPECL ADDITIVE PHASE NOISE Distribution Section only; does not
include PLL or external VCO/VCXO
CLK1 = 622.08 MHz, OUT = 622.08 MHz Input slew rate > 1 V/ns
Divide Ratio = 1
@ 10 Hz Offset −125 dBc/Hz
@ 100 Hz Offset −132 dBc/Hz
@ 1 kHz Offset −140 dBc/Hz
@ 10 kHz Offset −148 dBc/Hz
@ 100 kHz Offset −153 dBc/Hz
>1 MHz Offset −154 dBc/Hz
CLK1 = 622.08 MHz, OUT = 155.52 MHz
Divide Ratio = 4
@ 10 Hz Offset −128 dBc/Hz
@ 100 Hz Offset −140 dBc/Hz
@ 1 kHz Offset −148 dBc/Hz
@ 10 kHz Offset −155 dBc/Hz
@ 100 kHz Offset −161 dBc/Hz
>1 MHz Offset −161 dBc/Hz
CLK1 = 622.08 MHz, OUT = 38.88 MHz
Divide Ratio = 16
@ 10 Hz Offset −135 dBc/Hz
@ 100 Hz Offset −145 dBc/Hz
@ 1 kHz Offset −158 dBc/Hz
@ 10 kHz Offset −165 dBc/Hz
@ 100 kHz Offset −165 dBc/Hz
>1 MHz Offset −166 dBc/Hz
CLK1 = 491.52 MHz, OUT = 61.44 MHz
Divide Ratio = 8
@ 10 Hz Offset −131 dBc/Hz
@ 100 Hz Offset −142 dBc/Hz
@ 1 kHz Offset −153 dBc/Hz
@ 10 kHz Offset −160 dBc/Hz
@ 100 kHz Offset −165 dBc/Hz
>1 MHz Offset −165 dBc/Hz
CLK1 = 491.52 MHz, OUT = 245.76 MHz
Divide Ratio = 2
@ 10 Hz Offset −125 dBc/Hz
@ 100 Hz Offset −132 dBc/Hz
@ 1 kHz Offset −140 dBc/Hz
@ 10 kHz Offset −151 dBc/Hz
@ 100 kHz Offset −157 dBc/Hz
>1 MHz Offset −158 dBc/Hz
CLK1 = 245.76 MHz, OUT = 61.44 MHz
Divide Ratio = 4
@ 10 Hz Offset −138 dBc/Hz
@ 100 Hz Offset −144 dBc/Hz
@ 1 kHz Offset −154 dBc/Hz
@ 10 kHz Offset −163 dBc/Hz
@ 100 kHz Offset −164 dBc/Hz
>1 MHz Offset −165 dBc/Hz
AD9511
Rev. A | Page 10 of 60
Parameter Min Typ Max Unit Test Conditions/Comments
CLK1-TO-LVDS ADDITIVE PHASE NOISE Distribution Section only; does not
include PLL or external VCO/VCXO
CLK1 = 622.08 MHz, OUT= 622.08 MHz
Divide Ratio = 1
@ 10 Hz Offset −100 dBc/Hz
@ 100 Hz Offset −110 dBc/Hz
@ 1 kHz Offset −118 dBc/Hz
@ 10 kHz Offset −129 dBc/Hz
@ 100 kHz Offset −135 dBc/Hz
@ 1 MHz Offset −140 dBc/Hz
>10 MHz Offset −148 dBc/Hz
CLK1 = 622.08 MHz, OUT = 155.52 MHz
Divide Ratio = 4
@ 10 Hz Offset −112 dBc/Hz
@ 100 Hz Offset −122 dBc/Hz
@ 1 kHz Offset −132 dBc/Hz
@ 10 kHz Offset −142 dBc/Hz
@ 100 kHz Offset −148 dBc/Hz
@ 1 MHz Offset −152 dBc/Hz
>10 MHz Offset −155 dBc/Hz
CLK1 = 491.52 MHz, OUT = 245.76 MHz
Divide Ratio = 2
@ 10 Hz Offset −108 dBc/Hz
@ 100 Hz Offset −118 dBc/Hz
@ 1 kHz Offset −128 dBc/Hz
@ 10 kHz Offset −138 dBc/Hz
@ 100 kHz Offset −145 dBc/Hz
@ 1 MHz Offset −148 dBc/Hz
>10 MHz Offset −154 dBc/Hz
CLK1 = 491.52 MHz, OUT = 122.88 MHz
Divide Ratio = 4
@ 10 Hz Offset −118 dBc/Hz
@ 100 Hz Offset −129 dBc/Hz
@ 1 kHz Offset −136 dBc/Hz
@ 10 kHz Offset −147 dBc/Hz
@ 100 kHz Offset −153 dBc/Hz
@ 1 MHz Offset −156 dBc/Hz
>10 MHz Offset −158 dBc/Hz
CLK1 = 245.76 MHz, OUT = 245.76 MHz
Divide Ratio = 1
@ 10 Hz Offset −108 dBc/Hz
@ 100 Hz Offset −118 dBc/Hz
@ 1 kHz Offset −128 dBc/Hz
@ 10 kHz Offset −138 dBc/Hz
@ 100 kHz Offset −145 dBc/Hz
@ 1 MHz Offset −148 dBc/Hz
>10 MHz Offset −155 dBc/Hz
CLK1 = 245.76 MHz, OUT = 122.88 MHz
Divide Ratio = 2
@ 10 Hz Offset −118 dBc/Hz
@ 100 Hz Offset −127 dBc/Hz
@ 1 kHz Offset −137 dBc/Hz
@ 10 kHz Offset −147 dBc/Hz
AD9511
Rev. A | Page 11 of 60
Parameter Min Typ Max Unit Test Conditions/Comments
@ 100 kHz Offset −154 dBc/Hz
@ 1 MHz Offset −156 dBc/Hz
>10 MHz Offset −158 dBc/Hz
CLK1-TO-CMOS ADDITIVE PHASE NOISE Distribution Section only; does not
include PLL or external VCO/VCXO
CLK1 = 245.76 MHz, OUT = 245.76 MHz
Divide Ratio = 1
@ 10 Hz Offset −110 dBc/Hz
@ 100 Hz Offset −121 dBc/Hz
@ 1 kHz Offset −130 dBc/Hz
@ 10 kHz Offset −140 dBc/Hz
@ 100 kHz Offset −145 dBc/Hz
@ 1 MHz Offset −149 dBc/Hz
> 10 MHz Offset −156 dBc/Hz
CLK1 = 245.76 MHz, OUT = 61.44 MHz
Divide Ratio = 4
@ 10 Hz Offset −122 dBc/Hz
@ 100 Hz Offset −132 dBc/Hz
@ 1 kHz Offset −143 dBc/Hz
@ 10 kHz Offset −152 dBc/Hz
@ 100 kHz Offset −158 dBc/Hz
@ 1 MHz Offset −160 dBc/Hz
>10 MHz Offset −162 dBc/Hz
CLK1 = 78.6432 MHz, OUT = 78.6432 MHz
Divide Ratio = 1
@ 10 Hz Offset −122 dBc/Hz
@ 100 Hz Offset −132 dBc/Hz
@ 1 kHz Offset −140 dBc/Hz
@ 10 kHz Offset −150 dBc/Hz
@ 100 kHz Offset −155 dBc/Hz
@ 1 MHz Offset −158 dBc/Hz
>10 MHz Offset −160 dBc/Hz
CLK1 = 78.6432 MHz, OUT = 39.3216 MHz
Divide Ratio = 2
@ 10 Hz Offset −128 dBc/Hz
@ 100 Hz Offset −136 dBc/Hz
@ 1 kHz Offset −146 dBc/Hz
@ 10 kHz Offset −155 dBc/Hz
@ 100 kHz Offset −161 dBc/Hz
>1 MHz Offset −162 dBc/Hz
AD9511
Rev. A | Page 12 of 60
CLOCK OUTPUT ADDITIVE TIME JITTER
Table 6.
Parameter Min Typ Max Unit Test Conditions/Comments
LVPECL OUTPUT ADDITIVE TIME JITTER Distribution Section only; does not
include PLL or external VCO/VCXO
CLK1 = 622.08 MHz 40 fs rms BW = 12 kHz − 20 MHz (OC-12)
Any LVPECL (OUT0 to OUT2) = 622.08 MHz
Divide Ratio = 1
CLK1 = 622.08 MHz 55 fs rms BW = 12 kHz − 20 MHz (OC-3)
Any LVPECL (OUT0 to OUT2) = 155.52 MHz
Divide Ratio = 4
CLK1 = 400 MHz 215 fs rms Calculated from SNR of ADC method;
FC = 100 MHz with AIN = 170 MHz
Any LVPECL (OUT0 to OUT2) = 100 MHz
Divide Ratio = 4
CLK1 = 400 MHz 215 fs rms Calculated from SNR of ADC method;
FC = 100 MHz with AIN = 170 MHz
Any LVPECL (OUT0 to OUT2) = 100 MHz
Divide Ratio = 4
Other LVPECL = 100 MHz Interferer(s)
Both LVDS (OUT3, OUT4) = 100 MHz Interferer(s)
CLK1 = 400 MHz 222 fs rms Calculated from SNR of ADC method;
FC = 100 MHz with AIN = 170 MHz
Any LVPECL (OUT0 to OUT2) = 100 MHz
Divide Ratio = 4
Other LVPECL = 50 MHz Interferer(s)
Both LVDS (OUT3, OUT4) = 50 MHz Interferer(s)
CLK1 = 400 MHz 225 fs rms Calculated from SNR of ADC method;
FC = 100 MHz with AIN = 170 MHz
Any LVPECL (OUT0 to OUT2) = 100 MHz
Divide Ratio = 4
Other LVPECL = 50 MHz Interferer(s)
Both CMOS (OUT3, OUT4) = 50 MHz (B Outputs Off) Interferer(s)
CLK1 = 400 MHz 225 fs rms Calculated from SNR of ADC method;
FC = 100 MHz with AIN = 170 MHz
Any LVPECL (OUT0 to OUT2) = 100 MHz
Divide Ratio = 4
Other LVPECL = 50 MHz Interferer(s)
Both CMOS (OUT3, OUT4) = 50 MHz (B Outputs On) Interferer(s)
LVDS OUTPUT ADDITIVE TIME JITTER Distribution Section only; does not
include PLL or external VCO/VCXO
CLK1 = 400 MHz 264 fs rms Calculated from SNR of ADC method;
FC = 100 MHz with AIN = 170 MHz
LVDS (OUT3) = 100 MHz
Divide Ratio = 4
CLK1 = 400 MHz 319 fs rms Calculated from SNR of ADC method;
FC = 100 MHz with AIN = 170 MHz
LVDS (OUT4) = 100 MHz
Divide Ratio = 4
AD9511
Rev. A | Page 13 of 60
Parameter Min Typ Max Unit Test Conditions/Comments
CLK1 = 400 MHz 395 fs rms Calculated from SNR of ADC method;
FC = 100 MHz with AIN = 170 MHz
LVDS (OUT3) = 100 MHz
Divide Ratio = 4
LVDS (OUT4) = 50 MHz Interferer(s)
All LVPECL = 50 MHz Interferer(s)
CLK1 = 400 MHz 395 fs rms Calculated from SNR of ADC method;
FC = 100 MHz with AIN = 170 MHz
LVDS (OUT4) = 100 MHz
Divide Ratio = 4
LVDS (OUT3) = 50 MHz Interferer(s)
All LVPECL = 50 MHz Interferer(s)
CLK1 = 400 MHz 367 fs rms Calculated from SNR of ADC method;
FC = 100 MHz with AIN = 170 MHz
LVDS (OUT3) = 100 MHz
Divide Ratio = 4
CMOS (OUT4) = 50 MHz (B Outputs Off) Interferer(s)
All LVPECL = 50 MHz Interferer(s)
CLK1 = 400 MHz 367 fs rms Calculated from SNR of ADC method;
FC = 100 MHz with AIN = 170 MHz
LVDS (OUT4) = 100 MHz
Divide Ratio = 4
CMOS (OUT3) = 50 MHz (B Outputs Off) Interferer(s)
All LVPECL = 50 MHz Interferer(s)
CLK1 = 400 MHz 548 fs rms Calculated from SNR of ADC method;
FC = 100 MHz with AIN = 170 MHz
LVDS (OUT3) = 100 MHz
Divide Ratio = 4
CMOS (OUT4) = 50 MHz (B Outputs On) Interferer(s)
All LVPECL = 50 MHz Interferer(s)
CLK1 = 400 MHz 548 fs rms Calculated from SNR of ADC method;
FC = 100 MHz with AIN = 170 MHz
LVDS (OUT4) = 100 MHz
Divide Ratio = 4
CMOS (OUT3) = 50 MHz (B Outputs On) Interferer(s)
All LVPECL = 50 MHz Interferer(s)
CMOS OUTPUT ADDITIVE TIME JITTER Distribution Section only;
does not include PLL or external VCO/VCXO
CLK1 = 400 MHz 275 fs rms Calculated from SNR of ADC method;
FC = 100 MHz with AIN = 170 MHz
Both CMOS (OUT3, OUT4) = 100 MHz (B Output On)
Divide Ratio = 4
CLK1 = 400 MHz 400 fs rms Calculated from SNR of ADC method;
FC = 100 MHz with AIN = 170 MHz
CMOS (OUT3) = 100 MHz (B Output On)
Divide Ratio = 4
All LVPECL = 50 MHz Interferer(s)
LVDS (OUT4) = 50 MHz Interferer(s)
CLK1 = 400 MHz 374 fs rms Calculated from SNR of ADC method;
FC = 100 MHz with AIN = 170 MHz
CMOS (OUT3) = 100 MHz (B Output On)
Divide Ratio = 4
All LVPECL = 50 MHz Interferer(s)
CMOS (OUT4) = 50 MHz (B Output Off) Interferer(s)
AD9511
Rev. A | Page 14 of 60
Parameter Min Typ Max Unit Test Conditions/Comments
CLK1 = 400 MHz 555 fs rms Calculated from SNR of ADC method;
FC = 100 MHz with AIN = 170 MHz
CMOS (OUT3) = 100 MHz (B Output On)
Divide Ratio = 4
All LVPECL = 50 MHz Interferer(s)
CMOS (OUT4) = 50 MHz (B Output On) Interferer(s)
DELAY BLOCK ADDITIVE TIME JITTER1 Incremental additive jitter
100 MHz Output
Delay FS = 1 ns (1600 A, 1C) Fine Adj. 00000 0.61 ps
Delay FS = 1 ns (1600 A, 1C) Fine Adj. 11111 0.73 ps
Delay FS = 2 ns (800 A, 1C) Fine Adj. 00000 0.71 ps
Delay FS = 2 ns (800 A, 1C) Fine Adj. 11111 1.2 ps
Delay FS = 3 ns (800 A, 4C) Fine Adj. 00000 0.86 ps
Delay FS = 3 ns (800 A, 4C) Fine Adj. 11111 1.8 ps
Delay FS = 4 ns (400 A, 4C) Fine Adj. 00000 1.2 ps
Delay FS = 4 ns (400 A, 4C) Fine Adj. 11111 2.1 ps
Delay FS = 5 ns (200 A, 1C) Fine Adj. 00000 1.3 ps
Delay FS = 5 ns (200 A, 1C) Fine Adj. 11111 2.7 ps
Delay FS = 11 ns (200 A, 4C) Fine Adj. 00000 2.0 ps
Delay FS = 11 ns (200 A, 4C) Fine Adj. 00100 2.8 ps
1 This value is incremental. That is, it is in addition to the jitter of the LVDS or CMOS output without the delay. To estimate the total jitter, the LVDS or CMOS output jitter
should be added to this value using the root sum of the squares (RSS) method.
PLL AND DISTRIBUTION PHASE NOISE AND SPURIOUS
Table 7.
Parameter Min Typ Max Unit Test Conditions/Comments
PHASE NOISE AND SPURIOUS Depends on VCO/VCXO selection. Measured at LVPECL
clock outputs; ABP = 6 ns; ICP = 5 mA; Ref = 30.72 MHz.
VCXO = 245.76 MHz,
FPFD = 1.2288 MHz; R = 25, N = 200
VCXO is Toyocom TCO-2112 245.76.
245.76 MHz Output Divide by 1.
Phase Noise @100 kHz Offset <−145 dBc/Hz Dominated by VCXO phase noise.
Spurious <−97 dBc
First and second harmonics of FPFD.
Below measurement floor.
61.44 MHz Output Divide by 4.
Phase Noise @100 kHz Offset <−155 dBc/Hz Dominated by VCXO phase noise.
Spurious <−97 dBc
First and second harmonics of FPFD.
Below measurement floor.
AD9511
Rev. A | Page 15 of 60
SERIAL CONTROL PORT
Table 8.
Parameter Min Typ Max Unit Test Conditions/Comments
CSB, SCLK (INPUTS) CSB and SCLK have 30 kΩ
internal pull-down resistors
Input Logic 1 Voltage 2.0 V
Input Logic 0 Voltage 0.8 V
Input Logic 1 Current 110 µA
Input Logic 0 Current 1 µA
Input Capacitance 2 pF
SDIO (WHEN INPUT)
Input Logic 1 Voltage 2.0 V
Input Logic 0 Voltage 0.8 V
Input Logic 1 Current 10 nA
Input Logic 0 Current 10 nA
Input Capacitance 2 pF
SDIO, SDO (OUTPUTS)
Output Logic 1 Voltage 2.7 V
Output Logic 0 Voltage 0.4 V
TIMING
Clock Rate (SCLK, 1/tSCLK) 25 MHz
Pulse Width High, tPWH 16 ns
Pulse Width Low, tPWL 16 ns
SDIO to SCLK Setup, tDS 2 ns
SCLK to SDIO Hold, tDH 1 ns
SCLK to Valid SDIO and SDO, tDV 6 ns
CSB to SCLK Setup and Hold, tS, tH2 ns
CSB Minimum Pulse Width High, tPWH 3 ns
FUNCTION PIN
Table 9.
Parameter Min Typ Max Unit Test Conditions/Comments
INPUT CHARACTERISTICS The FUNCTION pin has a 30 kΩ internal pull-down resistor.
This pin should normally be held high. Do not leave NC.
Logic 1 Voltage 2.0 V
Logic 0 Voltage 0.8 V
Logic 1 Current 110 µA
Logic 0 Current 1 µA
Capacitance 2 pF
RESET TIMING
Pulse Width Low 50 ns
SYNC TIMING
Pulse Width Low 1.5 High speed clock cycles High speed clock is CLK1 or CLK2, whichever is
used for distribution.
AD9511
Rev. A | Page 16 of 60
STATUS PIN
Table 10.
Parameter Min Typ Max Unit Test Conditions/Comments
OUTPUT CHARACTERISTICS When selected as a digital output (CMOS); there are other modes
in which the STATUS pin is not CMOS digital output. See Figure 37.
Output Voltage High (VOH) 2.7 V
Output Voltage Low (VOL) 0.4 V
MAXIMUM TOGGLE RATE 100 MHz Applies when PLL mux is set to any divider or counter output,
or PFD up/down pulse. Also applies in analog lock detect mode.
Usually debug mode only. Beware that spurs may couple
to output when this pin is toggling.
ANALOG LOCK DETECT
Capacitance 3 pF
On-chip capacitance; used to calculate RC time
constant for analog lock detect readback. Use a pull-up resistor.
POWER
Table 11.
Parameter Min Typ Max Unit Test Conditions/Comments
POWER-UP DEFAULT MODE POWER DISSIPATION 550 600 mW Power-up default state; does not include power
dissipated in output load resistors. No clock.
POWER DISSIPATION 800 mW All outputs on. Three LVPECL outputs @ 800 MHz,
two CMOS out @ 62 MHz (5 pF load). Does not include
power dissipated in external resistors.
850 mW
All outputs on. Three LVPECL outputs @ 800 MHz,
two CMOS out @ 125 MHz (5 pF load). Does not include
power dissipated in external resistors.
Full Sleep Power-Down 35 60 mW Maximum sleep is entered by setting 0Ah<1:0> = 01b
and 58h<4> = 1b. This powers off the PLL BG and the
distribution BG references. Does not include power
dissipated in terminations.
Power-Down (PDB) 60 80 mW Set FUNCTION pin for PDB operation by setting
58h<6:5> = 11b. Pull PDB low. Does not include
power dissipated in terminations.
POWER DELTA
CLK1, CLK2 Power-Down 10 15 25 mW
Divider, DIV 2 − 32 to Bypass 23 27 33 mW For each divider.
LVPECL Output Power-Down (PD2, PD3) 50 65 75 mW For each output. Does not include dissipation
in termination (PD2 only).
LVDS Output Power-Down 80 92 110 mW For each output.
CMOS Output Power-Down (Static) 56 70 85 mW For each output. Static (no clock).
CMOS Output Power-Down (Dynamic) 115 150 190 mW For each CMOS output, single-ended. Clocking at
62 MHz with 5 pF load.
CMOS Output Power-Down (Dynamic) 125 165 210 mW For each CMOS output, single-ended. Clocking at
125 MHz with 5 pF load.
Delay Block Bypass 20 24 60 mW Vs. delay block operation at 1 ns fs with maximum
delay; output clocking at 25 MHz.
PLL Section Power-Down 5 15 40 mW
AD9511
Rev. A | Page 17 of 60
TIMING DIAGRAMS
05286-002
C
LK1
t
CMOS
t
CLK1
t
LVDS
t
PECL
Figure 2. CLK1/CLK1B to Clock Output Timing, DIV = 1 Mode
05286-064
DIFFERENTIAL
LVPECL
80%
20%
t
RP
t
FP
Figure 3. LVPECL Timing, Differential
05286-065
DIFFERENTIAL
LVDS
80%
20%
t
RL
t
FL
Figure 4. LVDS Timing, Differential
05286-066
SINGLE-ENDED
CMOS
3pF LOAD
80%
20%
t
RC
t
FC
Figure 5. CMOS Timing, Single-Ended, 3 pF Load
AD9511
Rev. A | Page 18 of 60
ABSOLUTE MAXIMUM RATINGS
Table 12.
Parameter or Pin
With
Respect
to Min Max Unit
VS GND −0.3 +3.6 V
VCP GND −0.3 +5.8 V
VCP VS−0.3 +5.8 V
REFIN, REFINB GND −0.3 VS + 0.3 V
RSET GND −0.3 VS + 0.3 V
CPRSET GND −0.3 VS + 0.3 V
CLK1, CLK1B, CLK2, CLK2B GND −0.3 VS + 0.3 V
CLK1 CLK1B −1.2 +1.2 V
CLK2 CLK2B −1.2 +1.2 V
SCLK, SDIO, SDO, CSB GND −0.3 VS + 0.3 V
OUT0, OUT1, OUT2, OUT3,
OUT4
GND −0.3 VS + 0.3 V
FUNCTION GND −0.3 VS + 0.3 V
STATUS GND −0.3 VS + 0.3 V
Junction Temperature 150 °C
Storage Temperature −65 +150 °C
Lead Temperature (10 sec) 300 °C
Stresses above those listed under Absolute Maximum Ratings
may cause permanent damage to the device. This is a stress
rating only; functional operation of the device at these or any
other conditions above those indicated in the operational
sections of this specification is not implied. Exposure to
absolute maximum ratings for extended periods may affect
device reliability.
THERMAL CHARACTERISTICS
Thermal Resistance1
48-Lead LFCSP
θJA = 28.5°C/W
1 Thermal impedance measurements were taken on a 4-layer board in still air,
in accordance with EIA/JESD51-7.
ESD CAUTION
ESD (electrostatic discharge) sensitive device. Electrostatic charges as high as 4000 V readily accumulate on
the human body and test equipment and can discharge without detection. Although this product features
proprietary ESD protection circuitry, permanent damage may occur on devices subjected to high energy
electrostatic discharges. Therefore, proper ESD precautions are recommended to avoid performance
degradation or loss of functionality.
AD9511
Rev. A | Page 19 of 60
PIN CONFIGURATION AND FUNCTION DESCRIPTIONS
PIN 1
INDICATOR
48
47
46
45
44
43
42
41
40
39
38
VS
CPRSET
GND
RSET
VS
GND
OUT0
OUT0B
VS
VS
GND
1
2
3
4
5
6
7
8
9
10
11
12
REFIN
REFINB
VS
VCP
CP
VS
CLK2
CLK2B
VS
CLK1
CLK1B
FUNCTION
VS
OUT3
OUT3B
VS
VS
OUT4
OUT4B
VS
VS
OUT1
OUT1B
VS
36
35
34
33
32
31
30
29
28
27
26
25
13
14
15
16
17
18
19
20
21
22
23
24
STATUS
SCLK
SDIO
SDO
CSB
VS
GND
OUT2B
OUT2
VS
VS
GND 37 GND
AD9511
TOP VIEW
(Not to Scale)
05286-003
Figure 6. 48-Lead LFCSP Pin Configuration
Note that the exposed paddle on this package is an electrical connection as well as a thermal enhancement. For the device to
function properly, the paddle must be attached to ground, GND.
AD9511
Rev. A | Page 20 of 60
Table 13. Pin Function Descriptions
Pin No. Mnemonic Description
1 REFIN PLL Reference Input.
2 REFINB Complementary PLL Reference Input.
3, 6, 9, 18, 22,
23, 25, 28, 29,
32, 33, 36, 39,
40, 44, 48
VS Power Supply (3.3 V).
4 VCP
Charge Pump Power Supply. It should be greater than or equal to VS.
VCP can be set as high as 5.5 V for VCOs, requiring extended tuning range.
5 CP Charge Pump Output.
7 CLK2
Clock Input. Used to connect external VCO/VCXO to feedback divider, N. CLK2 also drives the
distribution section of the chip and may be used as a generic clock input when PLL is not used.
8 CLK2B Complementary Clock Input. Used in conjunction with CLK2.
10 CLK1 Clock Input. Drives distribution section of the chip.
11 CLK1B Complementary Clock Input. Used in conjunction with CLK1.
12 FUNCTION
Multipurpose Input. May be programmed as a reset (RESETB), sync (SYNCB), or power-down (PDB) pin.
This pin is internally pulled down by a 30 kΩ resistor. If this pin is left NC, the part is in reset by default.
To avoid this, connect this pin to VS with a 1 kΩ resistor.
13 STATUS Output Used to Monitor PLL Status and Sync Status.
14 SCLK Serial Data Clock.
15 SDIO Serial Data I/O.
16 SDO Serial Data Output.
17 CSB Serial Port Chip Select.
19, 24, 37,
38, 43, 46
GND Ground.
20 OUT2B Complementary LVPECL Output.
21 OUT2 LVPECL Output.
26 OUT1B Complementary LVPECL Output.
27 OUT1 LVPECL Output.
30 OUT4B Complementary LVDS/Inverted CMOS Output. OUT4 includes a delay block.
31 OUT4 LVDS/CMOS Output. OUT4 includes a delay block.
34 OUT3B Complementary LVDS/Inverted CMOS Output.
35 OUT3 LVDS/CMOS Output.
41 OUT0B Complementary LVPECL Output.
42 OUT0 LVPECL Output.
45 RSET Current Set Resistor to Ground. Nominal value = 4.12 kΩ.
47 CPRSET Charge Pump Current Set Resistor to Ground. Nominal value = 5.1 kΩ.
Note that the exposed paddle on this package is an electrical connection as well as a thermal enhancement. For the device to
function properly, the paddle must be attached to ground, GND.
AD9511
Rev. A | Page 21 of 60
TERMINOLOGY
Phase Jitter and Phase Noise
An ideal sine wave can be thought of as having a continuous
and even progression of phase with time from 0 degrees to
360 degrees for each cycle. Actual signals, however, display a
certain amount of variation from ideal phase progression over
time. This phenomenon is called phase jitter. Although many
causes can contribute to phase jitter, one major cause is random
noise, which is characterized statistically as being Gaussian
(normal) in distribution.
This phase jitter leads to a spreading out of the energy of the
sine wave in the frequency domain, producing a continuous
power spectrum. This power spectrum is usually reported as a
series of values whose units are dBc/Hz at a given offset in
frequency from the sine wave (carrier). The value is a ratio
(expressed in dB) of the power contained within a 1 Hz
bandwidth with respect to the power at the carrier frequency.
For each measurement, the offset from the carrier frequency is
also given.
It is meaningful to integrate the total power contained within
some interval of offset frequencies (for example, 10 kHz to
10 MHz). This is called the integrated phase noise over that
frequency offset interval and can be readily related to the time
jitter due to the phase noise within that offset frequency
interval.
Phase noise has a detrimental effect on the performance of
ADCs, DACs, and RF mixers. It lowers the achievable dynamic
range of the converters and mixers, although they are affected
in somewhat different ways.
Time Jitter
Phase noise is a frequency domain phenomenon. In the time
domain, the same effect is exhibited as time jitter. When
observing a sine wave, the time of successive zero crossings is
seen to vary. In a square wave, the time jitter is seen as a
displacement of the edges from their ideal (regular) times of
occurrence. In both cases, the variations in timing from the
ideal are the time jitter. Since these variations are random in
nature, the time jitter is specified in units of seconds root mean
square (rms) or 1 sigma of the Gaussian distribution.
Time jitter that occurs on a sampling clock for a DAC or an
ADC decreases the SNR and dynamic range of the converter.
A sampling clock with the lowest possible jitter provides the
highest performance from a given converter.
Additive Phase Noise
It is the amount of phase noise that is attributable to the device
or subsystem being measured. The phase noise of any external
oscillators or clock sources has been subtracted. This makes it
possible to predict the degree to which the device impacts the
total system phase noise when used in conjunction with the
various oscillators and clock sources, each of which contribute
their own phase noise to the total. In many cases, the phase
noise of one element dominates the system phase noise.
Additive Time Jitter
It is the amount of time jitter that is attributable to the device
or subsystem being measured. The time jitter of any external
oscillators or clock sources has been subtracted. This makes it
possible to predict the degree to which the device will impact
the total system time jitter when used in conjunction with the
various oscillators and clock sources, each of which contribute
their own time jitter to the total. In many cases, the time jitter of
the external oscillators and clock sources dominates the system
time jitter.
AD9511
Rev. A | Page 22 of 60
TYPICAL PERFORMANCE CHARACTERISTICS
05286-080
OUTPUT FREQUENCY (MHz)
POWER (W)
0 800400
0.3
0.6
0.5
0.4
3 LVPECL (DIV ON) 2 LVDS (DIV ON)
DEFAULT – 3 LVPECL + 2 LVDS (DIV ON)
3 LVPECL + 2 LVDS (DIV BYPASSED)
Figure 7. Power vs. Frequency—LVPECL, LVDS (PLL Off)
05286-043
5MHz
CLK1 (EVAL BOARD)
3GHz
Figure 8. CLK1 Smith Chart (Evaluation Board)
05286-044
5MHz
CLK2 (EVAL BOARD)
3GHz
Figure 9. CLK2 Smith Chart (Evaluation Board)
05286-081
OUTPUT FREQUENCY (MHz)
POWER (W)
0 12010080604020
0.4
0.7
0.6
0.5
3 LVPECL + 2 CMOS (DIV ON)
Figure 10. Power vs. Frequency—LVPECL, CMOS (PLL Off)
05286-062
5GHz
REFIN (EVAL BOARD)
3GHz
Figure 11. REFIN Smith Chart (Evaluation Board)
AD9511
Rev. A | Page 23 of 60
05286-058
0
–10
10
–20
–30
–40
–50
–60
–70
–80
–90 CENTER 245.75MHz 30kHz/ SPAN 300kHz
Figure 12. Phase Noise, LVPECL, DIV 1, FVCXO = 245.76 MHz,
FOUT = 245.76 MHz, FPFD = 1.2288 MHz, R = 25, N = 200
05286-063
100
0
–10
–20
–30
–40
–50
–60
–70
–80
–90
CENTER 1.5GHz 250kHz/ SPAN 2.5MHz
Figure 13. PLL Reference Spurs: VCO 1.5 GHz, FPFD = 1 MHz
05286-041
VOLTAGE ON CP PIN (V)
CURRENT FROM CP PIN (mA)
0 0.5 1.0 1.5 2.0 2.5 3.0
0
0.5
1.0
1.5
2.0
2.5
3.0
3.5
4.0
4.5
5.0
PUMP DOWN PUMP UP
Figure 14. Charge Pump Output Characteristics @ VCPS = 3.3 V
05286-059
0
–10
10
–20
–30
–40
–50
–60
–70
–80
–90 CENTER 61.44MHz 30kHz/ SPAN 300kHz
Figure 15. Phase Noise, LVPECL, DIV 4, FVCXO = 245.76 MHz,
FOUT = 61.44 MHz, FPFD = 1.2288 MHz, R = 25, N = 200
05286-057
PFD FREQUENCY (MHz)
PFD NOISE REFERRED TO PFD INPUT (dBc/Hz)
0.1 100101
–170
–165
–160
–155
–150
–145
–140
–135
Figure 16. Phase Noise (Referred to CP Output) vs. PFD Frequency
05286-042
VOLTAGE ON CP PIN (V)
CURRENT FROM CP PIN (mA)
0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0
0
0.5
1.0
1.5
2.0
2.5
3.0
3.5
4.0
4.5
5.0
PUMP DOWN PUMP UP
Figure 17. Charge Pump Output Characteristics @ VCPS = 5.0 V
AD9511
Rev. A | Page 24 of 60
05286-053
VERT 500mV/DIV HORIZ 500ps/DIV
Figure 18. LVPECL Differential Output @ 800 MHz
05286-054
VERT 100mV/DIV HORI Z 500p s/DI V
Figure 19. LVDS Differential Output @ 800 MHz
05286-055
VERT 500mV/DI V HORIZ 1ns/ DIV
Figure 20. CMOS Single-Ended Output @ 250 MHz with 10 pF Load
05286-056
OUTPUT FREQUENCY (MHz)
DIFFERENTIAL SWING (V p-p)
100 16001100600
1.2
1.3
1.4
1.5
1.6
1.7
1.8
Figure 21. LVPECL Differential Output Swing vs. Frequency
05286-050
OUTPUT FREQUENCY (MHz)
DIFFERENTIAL SW ING (mV p-p)
100 900700500300
500
750
700
650
600
550
Figure 22. LVDS Differential Output Swing vs. Frequency
05286-047
OUTPUT FREQUENCY (MHz)
OUTPUT (V
PK
)
06500400300200100
0
3.5
3.0
2.5
2.0
1.5
1.0
0.5
2pF
10pF
20pF
00
Figure 23. CMOS Single-Ended Output Swing vs. Frequency and Load
AD9511
Rev. A | Page 25 of 60
05286-051
OFFSET (Hz)
L(f) (dBc/Hz)
10 10M1M100k10k1k100
–170
–110
–130
–120
–140
–150
–160
Figure 24. Additive Phase Noise—LVPECL DIV1, 245.76 MHz
Distribution Section Only
05286-048
OFFSET (Hz)
L(f) (dBc/Hz)
10 10M1M100k10k1k100
–170
–80
–90
–110
–100
–120
–130
–140
–150
–160
Figure 25. Additive Phase Noise—LVDS DIV1, 245.76 MHz
05286-045
OFFSET (Hz)
L(f) (dBc/Hz)
10 10M1M100k10k1k100
–170
–100
–110
–120
–130
–140
–150
–160
Figure 26. Additive Phase Noise—CMOS DIV1, 245.76 MHz
05286-052
OFFSET (Hz)
L(f) (dBc/Hz)
10 10M1M100k10k1k100
–170
–110
–130
–120
–140
–150
–160
Figure 27. Additive Phase Noise—LVPECL DIV1, 622.08 MHz
05286-049
OFFSET (Hz)
L(f) (dBc/Hz)
10 10M1M100k10k1k100
–170
–80
–90
–110
–100
–120
–130
–140
–150
–160
Figure 28. Additive Phase Noise—LVDS DIV2, 122.88 MHz
05286-046
OFFSET (Hz)
L(f) (dBc/Hz)
10 10M1M100k10k1k100
–170
–100
–110
–120
–130
–140
–150
–160
Figure 29. Additive Phase Noise—CMOS DIV4, 61.44 MHz
AD9511
Rev. A | Page 26 of 60
TYPICAL MODES OF OPERATION
PLL WITH EXTERNAL VCXO/VCO FOLLOWED BY
CLOCK DISTRIBUTION
This is the most common operational mode for the AD9511.
An external oscillator (shown as VCO/VCXO) is phase locked
to a reference input frequency applied to REFIN. The loop filter
is usually a passive design. A VCO or a VCXO can be used. The
CLK2 input is connected internally to the feedback divider, N.
The CLK2 input provides the feedback path for the PLL. If the
VCO/VCXO frequency exceeds maximum frequency of the
output(s) being used, an appropriate divide ratio must be set in
the corresponding divider(s) in the Distribution Section. Some
power can be saved by shutting off unused functions, as well as
by powering down any unused clock channels (see the Register
Map and Description section).
05286-010
R
NPFD
STATUS
CHARGE
PUMP
LVPECL
DIVIDE
LVPECL
DIVIDE
LVPECL
DIVIDE
LVDS/CMOS
DIVIDE
LVDS/CMOS
DIVIDE
Δ
T
FUNCTION
V
REF
AD9511
PLL
REF
CLK1 CLK2
REFERENCE
INPUT
REFIN
LOOP
FILTER
VCXO,
VCO
CLOCK
OUTPUTS
SERIAL
PORT
Figure 30. PLL and Clock Distribution Mode
CLOCK DISTRIBUTION ONLY
It is possible to use only the distribution section whenever the
PLL section is not needed. Some power can be saved by
shutting the PLL block off, as well as by powering down any
unused clock channels (see the Register Map Description
section).
In distribution mode, both the CLK1 and CLK2 inputs are
available for distribution to outputs via a low jitter multiplexer
(mux).
05286-011
R
NPFD
STATUS
CHARGE
PUMP
LVPECL
DIVIDE
LVPECL
DIVIDE
LVPECL
DIVIDE
LVDS/CMOS
DIVIDE
LVDS/CMOS
DIVIDE
Δ
T
FUNCTION
V
REF
AD9511
PLL
REF
CLK1 CLK2
CLOCK
INPUT 1
REFIN
CLOCK
INPUT 2
CLOCK
OUTPUTS
SERIAL
PORT
Figure 31. Clock Distribution Mode
AD9511
Rev. A | Page 27 of 60
PLL WITH EXTERNAL VCO AND BAND-PASS
FILTER FOLLOWED BY CLOCK DISTRIBUTION
An external band-pass filter may be used to try to improve the
phase noise and spurious characteristics of the PLL output. This
option is most appropriate to optimize cost by choosing a less
expensive VCO combined with a moderately priced filter. Note
that the BPF is shown outside of the VCO-to-N divider path,
with the BP filter outputs routed to CLK1. Some power can be
saved by shutting off unused functions, as well as by powering
down any unused clock channels (see the Register Map and
Description section).
05286-012
R
NPFD
STATUS
CHARGE
PUMP
LVPECL
DIVIDE
LVPECL
DIVIDE
LVPECL
DIVIDE
LVDS/CMOS
DIVIDE
LVDS/CMOS
DIVIDE
Δ
T
FUNCTION
V
REF
AD9511
PLL
REF
CLK1 CLK2
REFERENCE
INPUT
REFIN
LOOP
FILTER
VCO
BPF
CLOCK
OUTPUTS
SERIAL
PORT
Figure 32. AD9511 with VCO and BPF Filter
AD9511
Rev. A | Page 28 of 60
05286-004
R DIVIDER
N DIVIDER
PHASE
FREQUENCY
DETECTOR CHARGE
PUMP
PLL
SETTINGS
CLK2
STATUS
CLK2B
PROGRAMMABLE
DIVIDERS AND
PHASE ADJUST OUT0
OUT0B
LVPECL
/1, /2, /3... /31, /32
OUT1
OUT1B
LVPECL
/1, /2, /3... /31, /32
OUT2
OUT2B
LVPECL
/1, /2, /3... /31, /32
OUT3
OUT3B
LVDS/CMOS
/1, /2, /3... /31, /32
OUT4
OUT4B
LVDS/CMOS
/1, /2, /3... /31, /32
DELAY
ADJUST
Δ
T
CLK1
CLK1B
REFIN
REFINB
FUNCTION
SCLK
SDIO
SDO
CSB
SERIAL
CONTROL
PORT
CP
CPRSET
DISTRIBUTION
REF
SYNCB,
RESETB
PDB
RSET
AD9511
GNDVS VCP
PLL
REF
1.6GHz
1.2GHz
LVPECL
250MHz
CMOS
800MHz
LVDS
250MHz
1.6GHz
Figure 33. Functional Block Diagram Showing Maximum Frequencies
AD9511
Rev. A | Page 29 of 60
FUNCTIONAL DESCRIPTION
OVERALL
Figure 33 shows a block diagram of the AD9511. The chip
combines a programmable PLL core with a configurable clock
distribution system. A complete PLL requires the addition of a
suitable external VCO (or VCXO) and loop filter. This PLL can
lock to a reference input signal and produce an output that is
related to the input frequency by the ratio defined by the
programmable R and N dividers. The PLL cleans up some jitter
from the external reference signal, depending on the loop
bandwidth and the phase noise performance of the VCO
(VCXO).
The output from the VCO (VCXO) can be applied to the clock
distribution section of the chip, where it can be divided by any
integer value from 1 to 32. The duty cycle and relative phase of
the outputs can be selected. There are three LVPECL outputs
(OUT0, OUT1, and OUT2) and two outputs that can be either
LVDS or CMOS level outputs (OUT3 or OUT4). OUT4 can
also make use of a variable delay block.
Alternatively, the clock distribution section can be driven
directly by an external clock signal, and the PLL can be powered
off. Whenever the clock distribution section is used alone, there
is no clock clean-up. The jitter of the input clock signal is
passed along directly to the distribution section and may
dominate at the clock outputs.
PLL SECTION
The AD9511 consists of a PLL section and a distribution
section. If desired, the PLL section can be used separately from
the distribution section.
The AD9511 has a complete PLL core on-chip, requiring only
an external loop filter and VCO/VCXO. This PLL is based on
the ADF4106, a PLL noted for its superb low phase noise
performance. The operation of the AD9511 PLL is nearly
identical to that of the ADF4106, offering an advantage to those
with experience with the ADF series of PLLs. Differences
include the addition of differential inputs at REFIN and CLK2,
and a different control register architecture. Also, the prescaler
has been changed to allow N as low as 1. The AD9511 PLL
implements the digital lock detect feature somewhat differently
than the ADF4106 does, offering improved functionality at
higher PFD rates. See the Register Map Description section.
PLL Reference Input—REFIN
The REFIN/REFINB pins can be driven by either a differential
or a single-ended signal. These pins are internally self-biased so
that they can be ac-coupled via capacitors. It is possible to dc-
couple to these inputs. If REFIN is driven single-ended, the
unused side (REFINB) should be decoupled via a suitable
capacitor to a quiet ground. Figure 34 shows the equivalent
circuit of REFIN.
05286-033
V
S
REFIN
REFINB 150Ω
150Ω
10kΩ12kΩ
10kΩ10kΩ
Figure 34. REFIN Equivalent Circuit
VCO/VCXO Clock Input—CLK2
The CLK2 differential input is used to connect an external VCO
or VCXO to the PLL. Only the CLK2 input port has a
connection to the PLL N divider. This input can receive up to
1.6 GHz. These inputs are internally self-biased and must be ac-
coupled via capacitors.
Alternatively, CLK2 may be used as an input to the distribution
section. This is accomplished by setting Register 45h<0> = 0b.
The default condition is for CLK1 to feed the distribution section.
05286-016
V
S
CLOCK INPUT
STAGE
CLK
CLKB
5kΩ
5kΩ
2.5kΩ2.5kΩ
Figure 35. CLK1, CLK2 Equivalent Input Circuit
PLL Reference Divider—R
The REFIN/REFINB inputs are routed to reference divider, R,
which is a 14-bit counter. R may be programmed to any value
from 1 to 16383 (a value of 0 results in a divide by 1) via its
control register (OBh<5:0>, OCh<7:0>). The output of the R
divider goes to one of the phase/frequency detector inputs. The
maximum allowable frequency into the phase, frequency
detector (PFD) must not be exceeded. This means that the
REFIN frequency divided by R must be less than the maximum
allowable PFD frequency. See Figure 34.
VCO/VCXO Feedback Divider—N (P, A, B)
The N divider is a combination of a prescaler, P, (3 bits) and two
counters, A (6 bits) and B (13 bits). Although the AD9511’s PLL
is similar to the ADF4106, the AD9511 has a redesigned
prescaler that allows lower values of N. The prescaler has both a
dual modulus (DM) and a fixed divide (FD) mode. The
AD9511 prescaler modes are shown in Tabl e 14.
AD9511
Rev. A | Page 30 of 60
Table 14. PLL Prescaler Modes
Mode
(FD = Fixed Divide
DM = Dual Modulus) Value in 0Ah<4:2> Divide By
FD 000 1
FD 001 2
P = 2 DM 010 P/P + 1 = 2/3
P = 4 DM 011 P/P + 1 = 4/5
P = 8 DM 100 P/P + 1 = 8/9
P = 16 DM 101 P/P + 1 = 16/17
P = 32 DM 110 P/P + 1 = 32/33
FD 111 3
When using the prescaler in FD mode, the A counter is not
used, and the B counter may need to be bypassed. The DM
prescaler modes set some upper limits on the frequency, which
can be applied to CLK2. See Table 15.
Table 15. Frequency Limits of Each Prescaler Mode
A and B Counters
The AD9511 B counter has a bypass mode (B = 1), which is not
available on the ADF4106. The B counter bypass mode is valid
only when using the prescaler in FD mode. The B counter is
bypassed by writing 1 to the B counter bypass bit (0Ah<6> =
1b). The valid range of the B counter is 3 to 8191. The default
after a reset is 0, which is invalid.
Note that the A counter is not used when the prescaler is in
FD mode.
Note also that the A/B counters have their own reset bit,
which is primarily intended for testing. The A and B counters
can also be reset using the R, A, and B counters’ shared reset bit
(09h<0>).
Determining Values for P, A, B, and R
When operating the AD9511 in a dual-modulus mode, the
input reference frequency, FREF, is related to the VCO output
frequency, FVCO.
FVCO = (FREF/R) × (PB + A) = FREF × N/R
When operating the prescaler in fixed divide mode, the A
counter is not used and the equation simplifies to
FVCO = (FREF/R) × (PB) = FREF × N/R
By using combinations of dual modulus and fixed divide
modes, the AD9511 can achieve values of N all the way down to
N = 1. Table 16 shows how a 10 MHz reference input may be
locked to any integer multiple of N. Note that the same value of
N may be derived in different ways, as illustrated by N = 12.
Table 16. P, A, B, R—Smallest Values for N
FREF R P A B N FVCO Mode Notes
10 1 1 X 1 1 10 FD P = 1, B = 1 (Bypassed)
10 1 2 X 1 2 20 FD P = 2, B = 1 (Bypassed)
10 1 1 X 3 3 30 FD P = 1, B = 3
10 1 1 X 4 4 40 FD P = 1, B = 4
10 1 1 X 5 5 50 FD P = 1, B = 5
10 1 2 X 3 6 60 FD P = 2, B = 3
10 1 2 0 3 6 60 DM P/P + 1 = 2/3, A = 0, B = 3
10 1 2 1 3 7 70 DM P/P + 1 = 2/3, A = 1, B = 3
10 1 2 2 3 8 80 DM P/P + 1 = 2/3, A = 2, B = 3
10 1 2 1 4 9 90 DM P/P + 1 = 2/3, A = 1, B = 4
10 1 2 X 5 10 100 FD P = 2, B = 5
10 1 2 0 5 10 100 DM P/P + 1 = 2/3, A = 0, B = 5
10 1 2 1 5 11 110 DM P/P + 1 = 2/3, A = 1, B = 5
10 1 2 X 6 12 120 FD P = 2, B = 6
10 1 2 0 6 12 120 DM P/P + 1 = 2/3, A = 0, B = 6
10 1 4 0 3 12 120 DM P/P + 1 = 4/5, A = 0, B = 3
10 1 4 1 3 13 130 DM P/P + 1 = 4/5, A = 1, B = 3
Mode (DM = Dual Modulus) CLK2
P = 2 DM (2/3) <600 MHz
P = 4 DM (4/5) <1000 MHz
P = 8 DM (8/9) <1600 MHz
P = 16 DM <1600 MHz
P = 32 DM <1600 MHz
AD9511
Rev. A | Page 31 of 60
Phase Frequency Detector (PFD) and Charge Pump
The PFD takes inputs from the R counter and the N counter
(N = BP + A) and produces an output proportional to the phase
and frequency difference between them. Figure 36 is a
simplified schematic. The PFD includes a programmable delay
element that controls the width of the antibacklash pulse. This
pulse ensures that there is no dead zone in the PFD transfer
function and minimizes phase noise and reference spurs. Two
bits in Register 0Dh <1:0> control the width of the pulse.
05286-014
D1 Q1
U1
CLR1
R DIVIDER
HI UP
D2 Q2
U2
CLR2
N DIVIDER
HI DOWN
CP
CHARGE
PUMP
V
P
GND
U3
PROGRAMMABLE
DELAY
ANTIBACKLASH
PULSE WIDTH
Figure 36. PFD Simplified Schematic and Timing (In Lock)
Antibacklash Pulse
The PLL features a programmable antibacklash pulse width that
is set by the value in Register 0Dh<1:0>. The default
antibacklash pulse width is 1.3 ns (0Dh<1:0> = 00b) and
normally should not need to be changed. The antibacklash
pulse eliminates the dead zone around the phase-locked
condition and thereby reduces the potential for certain spurs
that could be impressed on the VCO signal.
STATUS Pin
The output multiplexer on the AD9511 allows access to various
signals and internal points on the chip at the STATUS pin.
Figure 37 shows a block diagram of the STATUS pin section.
The function of the STATUS pin is controlled by Register
08h<5:2>.
PLL Digital Lock Detect
The STATUS pin can display two types of PLL lock detect:
digital (DLD) and analog (ALD). Whenever digital lock detect
is desired, the STATUS pin provides a CMOS level signal, which
can be active high or active low.
The digital lock detect has one of two time windows, as selected
by Register 0Dh<5>. The default (ODh<5> = 0b) requires the
signal edges on the inputs to the PFD to be coincident within
9.5 ns to set the DLD true, which then must separate by at least
15 ns to give DLD = false.
The other setting (ODh<5> = 1b) makes these coincidence
times 3.5 ns for DLD = true and 7 ns for DLD = false.
The DLD may be disabled by writing 1 to Register 0Dh<6>.
If the signal at REFIN goes away while DLD is true, the DLD
will not necessarily indicate loss-of-lock. See the Loss of
Reference section for more information.
0
5286-015
OFF (LOW) (DEFAULT)
DIGITAL LOCK DETECT (ACTIVE HIGH)
N DIVIDER OUTPUT
DIGITAL LOCK DETECT (ACTIVE LOW)
R DIVIDER OUTPUT
ANALOG LOCK DETECT (N-CHANNEL OPEN DRAIN)
A COUNTER OUTPUT
PRESCALER OUTPUT (NCLK)
PFD UP PULSE
PFD DOWN PULSE
LOSS OF REFERENCE (ACTIVE HIGH)
TRI-STATE
ANALOG LOCK DETECT (P-CHANNEL OPEN DRAIN)
LOSS OF REFERENCE OR LOCK DETECT (ACTIVE HIGH)
LOSS OF REFERENCE OR LOCK DETECT (ACTIVE LOW)
LOSS OF REFERENCE (ACTIVE LOW)
PLL MUX CONTROL
08h <5:2>
SYNC DETECT ENABLE
58h <0>
SYNC
DETECT
CONTROL FOR ANALOG
LOCK DETECT MODE
V
S
GND
STATUS
PIN
Figure 37. STATUS Pin Circuit CLK1 Clock Input
AD9511
Rev. A | Page 32 of 60
PLL Analog Lock Detect
An analog lock detect (ALD) signal may be selected. When
ALD is selected, the signal at the STATUS pin is either an open-
drain P-channel (08h<5:2> = 1100b) or an open-drain N-
channel (08h<5:2> = 0101b).
The analog lock detect signal is true (relative to the selected
mode) with brief false pulses. These false pulses get shorter as
the inputs to the PFD are nearer to coincidence and longer as
they are further from coincidence.
To extract a usable analog lock detect signal, an external RC
network is required to provide an analog filter with the
appropriate RC constant to allow for the discrimination of a
lock condition by an external voltage comparator. A 1 kΩ
resistor in parallel with a small capacitance usually fulfills this
requirement. However, some experimentation may be required
to get the desired operation.
The analog lock detect function may introduce some spurious
energy into the clock outputs. It is prudent to limit the use of
the ALD when the best possible jitter/phase noise performance
is required on the clock outputs.
Loss of Reference
The AD9511 PLL can warn of a loss-of-reference signal at
REFIN. The loss-of-reference monitor internally sets a flag
called LREF. Externally, this signal can be observed in several
ways on the STATUS pin, depending on the PLL MUX control
settings in Register 08h<5:2>. The LREF alone can be observed
as an active high signal by setting 08h<5:2> = <1010b> or as an
active low signal by setting 08h<5:2> = <1111b>.
The loss-of-reference circuit is clocked by the signal from the
VCO, which means that there must be a VCO signal present to
detect a loss of reference.
The digital lock detect (DLD) block of the AD9511 requires a
PLL reference signal to be present for the digital lock detect
output to be valid. It is possible to have a digital lock detect
indication (DLD = true) that remains true even after a loss-of-
reference signal. For this reason, the digital lock detect signal
alone cannot be relied upon if the reference has been lost. There
is a way to combine the DLD and the LREF into a single signal
at the STATUS pin. Set 08h<5:2> = <1101b> to get a signal that
is the logical OR of the loss-of-lock (inverse of DLD) and the
loss-of-reference (LREF) active high. If an active low version of
this same signal is desired, set 08h<5:2> = <1110b>.
The reference monitor is enabled only after the DLD signal has
been high for the number of PFD cycles set by the value in
07h<6:5>. This delay is measured in PFD cycles. The delay
ranges from 3 PFD cycles (default) to 24 PFD cycles. When the
reference goes away, LREF goes true and the charge pump goes
into tri-state.
User intervention is required to take the part out of this state.
First, 07h<2> = 0b must be written in order to disable the loss-
of-reference circuit, taking the charge pump out of tri-state and
causing LREF to go false. A second write of 07h<2> = 1b is
required to re-enable the loss-of-reference circuit.
0
5286-034
PLL LOOP LOCKS
DLD GOE S TRUE
LREF IS FALSE
CHECK F O R P RES E NCE
OF RE F E RE NCE.
LREF STAYS FALSE I F
REF E R ENCE I S DETE CTED.
CHARGE PUMP
GOES I NTO TRI-STATE.
LREF SET TRUE. MISSING
REFERENCE
DETECTED
n P F D CYCLES WI T H
DLD T RUE
(n SET BY 07h<6:5>)
WRITE 07h<2> = 0
LREF SET FALSE
CHARGE P UMP CO M E S
OUT OF TRI-STATE
WRITE 07h<2> = 1
LO R E NABL E D
Figure 38. Loss of Reference Sequence of Events
FUNCTION PIN
The FUNCTION pin (12) has three functions that are selected
by the value in Register 58h<6:5>. This pin is internally pulled
down by a 30 kΩ resistor. If this pin is left NC, the part is in
reset by default. To avoid this, connect this pin to VS with a
1 kΩ resistor.
RESETB: 58h<6:5> = 00b (Default)
In its default mode, the FUNCTION pin acts as RESETB, which
generates an asynchronous reset or hard reset when pulled low.
The resulting reset writes the default values into the serial
control port buffer registers as well as loading them into the
chip control registers. When the RESETB signal goes high
again, a synchronous sync is issued (see the SYNCB: 58h<6:5>
= 01b section) and the AD9511 resumes operation according to
the default values of the registers.
SYNCB: 58h<6:5> = 01b
The FUNCTION pin may be used to cause a synchronization or
alignment of phase among the various clock outputs. The
synchronization applies only to clock outputs that:
• are not powered down
• the divider is not masked (no sync = 0b)
• are not bypassed (bypass = 0b)
SYNCB is level and rising edge sensitive. When SYNCB is low,
the set of affected outputs are held in a predetermined state,
defined by each divider’s start high bit. On a rising edge, the
dividers begin after a predefined number of fast clock cycles
(fast clock is the selected clock input, CLK1 or CLK2) as
determined by the values in the divider’s phase offset bits.
The SYNCB application of the FUNCTION pin is always active,
regardless of whether the pin is also assigned to perform reset
AD9511
Rev. A | Page 33 of 60
or power-down. When the SYNCB function is selected, the
FUNCTION pin does not act as either RESETB or PDB.
PDB: 58h<6:5> = 11b
The FUNCTION pin may also be programmed to work as an
asynchronous full power-down, PDB. Even in this full power-
down mode, there is still some residual VS current because
some on-chip references continue to operate. In PDB mode, the
FUNCTION pin is active low. The chip remains in a power-
down state until PDB is returned to logic high. The chip returns
to the settings programmed prior to the power-down.
See the Chip Power-Down or Sleep Mode—PDB section for
more details on what occurs during a PDB initiated power-
down.
DISTRIBUTION SECTION
As previously mentioned, the AD9511 is partitioned into two
operational sections: PLL and distribution. The PLL Section
was discussed previously. If desired, the distribution section can
be used separately from the PLL section.
CLK1 AND CLK2 CLOCK INPUTS
Either CLK1 or CLK2 may be selected as the input to the
distribution section. The CLK1 input can be connected to drive
the distribution section only. CLK1 is selected as the source for
the distribution section by setting Register 45h<0> = 1. This is
the power-up default state.
CLK1 and CLK2 work for inputs up to 1600 MHz. The jitter
performance is improved by a higher input slew rate. The input
level should be between approximately 150 mV p-p to no more
than 2 V p-p. Anything greater may result in turning on the
protection diodes on the input pins, which could degrade the
jitter performance.
See Figure 35 for the CLK1 and CLK2 equivalent input circuit.
These inputs are fully differential and self-biased. The signal
should be ac-coupled using capacitors. If a single-ended input
must be used, this can be accommodated by ac coupling to one
side of the differential input only. The other side of the input
should be bypassed to a quiet ac ground by a capacitor.
The unselected clock input (CLK1 or CLK2) should be powered
down to eliminate any possibility of unwanted crosstalk
between the selected clock input and the unselected clock input.
DIVIDERS
Each of the five clock outputs of the AD9511 has its own
divider. The divider can be bypassed to get an output at the
same frequency as the input (1×). When a divider is bypassed, it
is powered down to save power.
All integer divide ratios from 1 to 32 may be selected. A divide
ratio of 1 is selected by bypassing the divider.
Each divider can be configured for divide ratio, phase, and duty
cycle. The phase and duty cycle values that can be selected
depend on the divide ratio that is chosen.
Setting the Divide Ratio
The divide ratio is determined by the values written via the SCP
to the registers that control each individual output, OUT0 to
OUT4. These are the even numbered registers beginning at 4Ah
and going through 52h. Each of these registers is divided into
bits that control the number of clock cycles the divider output
stays high (high_cycles <3:0>) and the number of clock cycles
the divider output stays low (low_cycles <7:4>). Each value is 4
bits and has the range of 0 to 15.
The divide ratio is set by
Divide Ratio = (high_cycles + 1) + (low_cycles + 1)
Example 1:
Set the Divide Ratio = 2
high_cycles = 0
low_cycles = 0
Divide Ratio = (0 + 1) + (0 + 1) = 2
Example 2:
Set Divide Ratio = 8
high_cycles = 3
low_cycles = 3
Divide Ratio = (3 + 1) + (3 + 1) = 8
Note that a Divide Ratio of 8 may also be obtained by setting:
high_cycles = 2
low_cycles = 4
Divide Ratio = (2 + 1) + (4 + 1) = 8
Although the second set of settings produce the same divide
ratio, the resulting duty cycle is not the same.
Setting the Duty Cycle
The duty cycle and the divide ratio are related. Different divide
ratios have different duty cycle options. For example, if Divide
Ratio = 2, the only duty cycle possible is 50%. If the Divide
Ratio = 4, the duty cycle may be 25%, 50%, or 75%.
The duty cycle is set by
Duty Cycle = (high_cycles + 1)/[(high_cycles + 1) + (low_cycles + 1)]
See Table 17 for the values of the available duty cycles for each
divide ratio.
AD9511
Rev. A | Page 34 of 60
Table 17. Duty Cycle and Divide Ratio
4Ah to 52h
Divide Ratio Duty Cycle (%) LO<7:4> HI<3:0>
2 50 0 0
3 67 0 1
3 33 1 0
4 50 1 1
4 75 0 2
4 25 2 0
5 60 1 2
5 40 2 1
5 80 0 3
5 20 3 0
6 50 2 2
6 67 1 3
6 33 3 1
6 83 0 4
6 17 4 0
7 57 2 3
7 43 3 2
7 71 1 4
7 29 4 1
7 86 0 5
7 14 5 0
8 50 3 3
8 63 2 4
8 38 4 2
8 75 1 5
8 25 5 1
8 88 0 6
8 13 6 0
9 56 3 4
9 44 4 3
9 67 2 5
9 33 5 2
9 78 1 6
9 22 6 1
9 89 0 7
9 11 7 0
10 50 4 4
10 60 3 5
10 40 5 3
10 70 2 6
10 30 6 2
10 80 1 7
10 20 7 1
10 90 0 8
10 10 8 0
11 55 4 5
11 45 5 4
11 64 3 6
11 36 6 3
11 73 2 7
4Ah to 52h
Divide Ratio Duty Cycle (%) LO<7:4> HI<3:0>
11 27 7 2
11 82 1 8
11 18 8 1
11 91 0 9
11 9 9 0
12 50 5 5
12 58 4 6
12 42 6 4
12 67 3 7
12 33 7 3
12 75 2 8
12 25 8 2
12 83 1 9
12 17 9 1
12 92 0 A
12 8 A 0
13 54 5 6
13 46 6 5
13 62 4 7
13 38 7 4
13 69 3 8
13 31 8 3
13 77 2 9
13 23 9 2
13 85 1 A
13 15 A 1
13 92 0 B
13 8 B 0
14 50 6 6
14 57 5 7
14 43 7 5
14 64 4 8
14 36 8 4
14 71 3 9
14 29 9 3
14 79 2 A
14 21 A 2
14 86 1 B
14 14 B 1
14 93 0 C
14 7 C 0
15 53 6 7
15 47 7 6
15 60 5 8
15 40 8 5
15 67 4 9
15 33 9 4
15 73 3 A
15 27 A 3
15 80 2 B
AD9511
Rev. A | Page 35 of 60
4Ah to 52h
Divide Ratio Duty Cycle (%) LO<7:4> HI<3:0>
15 20 B 2
15 87 1 C
15 13 C 1
15 93 0 D
15 7 D 0
16 50 7 7
16 56 6 8
16 44 8 6
16 63 5 9
16 38 9 5
16 69 4 A
16 31 A 4
16 75 3 B
16 25 B 3
16 81 2 C
16 19 C 2
16 88 1 D
16 13 D 1
16 94 0 E
16 6 E 0
17 53 7 8
17 47 8 7
17 59 6 9
17 41 9 6
17 65 5 A
17 35 A 5
17 71 4 B
17 29 B 4
17 76 3 C
17 24 C 3
17 82 2 D
17 18 D 2
17 88 1 E
17 12 E 1
17 94 0 F
17 6 F 0
18 50 8 8
18 56 7 9
18 44 9 7
18 61 6 A
18 39 A 6
18 67 5 B
18 33 B 5
18 72 4 C
18 28 C 4
18 78 3 D
18 22 D 3
18 83 2 E
18 17 E 2
18 89 1 F
18 11 F 1
4Ah to 52h
Divide Ratio Duty Cycle (%) LO<7:4> HI<3:0>
19 53 8 9
19 47 9 8
19 58 7 A
19 42 A 7
19 63 6 B
19 37 B 6
19 68 5 C
19 32 C 5
19 74 4 D
19 26 D 4
19 79 3 E
19 21 E 3
19 84 2 F
19 16 F 2
20 50 9 9
20 55 8 A
20 45 A 8
20 60 7 B
20 40 B 7
20 65 6 C
20 35 C 6
20 70 5 D
20 30 D 5
20 75 4 E
20 25 E 4
20 80 3 F
20 20 F 3
21 52 9 A
21 48 A 9
21 57 8 B
21 43 B 8
21 62 7 C
21 38 C 7
21 67 6 D
21 33 D 6
21 71 5 E
21 29 E 5
21 76 4 F
21 24 F 4
22 50 A A
22 55 9 B
22 45 B 9
22 59 8 C
22 41 C 8
22 64 7 D
22 36 D 7
22 68 6 E
22 32 E 6
22 73 5 F
22 27 F 5
23 52 A B
AD9511
Rev. A | Page 36 of 60
4Ah to 52h
Divide Ratio Duty Cycle (%) LO<7:4> HI<3:0>
23 48 B A
23 57 9 C
23 43 C 9
23 61 8 D
23 39 D 8
23 65 7 E
23 35 E 7
23 70 6 F
23 30 F 6
24 50 B B
24 54 A C
24 46 C A
24 58 9 D
24 42 D 9
24 63 8 E
24 38 E 8
24 67 7 F
24 33 F 7
25 52 B C
25 48 C B
25 56 A D
25 44 D A
25 60 9 E
25 40 E 9
25 64 8 F
25 36 F 8
26 50 C C
26 54 B D
4Ah to 52h
Divide Ratio Duty Cycle (%) LO<7:4> HI<3:0>
26 46 D B
26 58 A E
26 42 E A
26 62 9 F
26 38 F 9
27 52 C D
27 48 D C
27 56 B E
27 44 E B
27 59 A F
27 41 F A
28 50 D D
28 54 C E
28 46 E C
28 57 B F
28 43 F B
29 52 D E
29 48 E D
29 55 C F
29 45 F C
30 50 E E
30 53 D F
30 47 F D
31 52 E F
31 48 F E
32 50 F F
AD9511
Rev. A | Page 37 of 60
Divider Phase Offset
The phase of each output may be selected, depending on the
divide ratio chosen. This is selected by writing the appropriate
values to the registers, which set the phase and start high/low
bit for each output. These are the odd numbered registers from
4Bh to 53h. Each divider has a 4-bit phase offset <3:0> and a
start high or low bit <4>.
Following a sync pulse, the phase offset word determines how
many fast clock (CLK1 or CLK2) cycles to wait before initiating
a clock output edge. The Start H/L bit determines if the divider
output starts low or high. By giving each divider a different
phase offset, output-to-output delays can be set in increments of
the fast clock period, tCLK.
Figure 39 shows three dividers, each set for DIV = 4, 50% duty
cycle. By incrementing the phase offset from 0 to 2, each output
is offset from the initial edge by a multiple of tCLK.
0
5286-091
123456789101112131415
0
CLOCK INPUT
CLK
DIVIDER OTUPUTS
DIV = 4, DUTY = 50%
START = 0,
PHASE = 0
START = 0,
PHASE = 1
START = 0,
PHASE = 2
t
CLK
t
CLK
2
×t
CLK
Figure 39. Phase Offset—All Dividers Set for DIV = 4, Phase Set from 0 to 2
For example:
CLK1 = 491.52 MHz
tCLK1 = 1/491.52 = 2.0345 ns
For DIV = 4
Phase Offset 0 = 0 ns
Phase Offset 1 = 2.0345 ns
Phase Offset 2 = 4.069 ns
The three outputs may also be described as:
OUT1 = 0°
OUT2 = 90°
OUT3 = 180°
Setting the phase offset to Phase = 4 results in the same relative
phase as the first channel, Phase = 0° or 360°.
In general, by combining the 4-bit phase offset and the Start
H/L bit, there are 32 possible phase offset states (see Table 18).
Table 18. Phase Offset—Start H/L Bit
4Bh to 53h
Phase Offset
(Fast Clock
Rising Edges) Phase Offset <3:0> Start H/L <4>
0 0 0
1 1 0
2 2 0
3 3 0
4 4 0
5 5 0
6 6 0
7 7 0
8 8 0
9 9 0
10 10 0
11 11 0
12 12 0
13 13 0
14 14 0
15 15 0
16 0 1
17 1 1
18 2 1
19 3 1
20 4 1
21 5 1
22 6 1
23 7 1
24 8 1
25 9 1
26 10 1
27 11 1
28 12 1
29 13 1
30 14 1
31 15 1
The resolution of the phase offset is set by the fast clock period
(tCLK) at CLK1 or CLK2. As a result, every divide ratio does not
have 32 unique phase offsets available. For any divide ratio, the
number of unique phase offsets is numerically equal to the
divide ratio (see Tabl e 18):
DIV = 4
Unique Phase Offsets Are Phase = 0, 1, 2, 3
DIV= 7
Unique Phase Offsets Are Phase = 0, 1, 2, 3, 4, 5, 6
AD9511
Rev. A | Page 38 of 60
DIV = 18
Unique Phase Offsets Are Phase = 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10,
11, 12, 13, 14, 15, 16, 17
Phase offsets may be related to degrees by calculating the phase
step for a particular divide ratio:
Phase Step = 360°/(Divide Ratio) = 360°/DIV
Using some of the same examples,
DIV = 4
Phase Step = 360°/4 = 90°
Unique Phase Offsets in Degrees Are Phase = 0°, 90°,
180°, 270°
DIV = 7
Phase Step = 360°/7 = 51.43°
Unique Phase Offsets in Degrees Are Phase = 0°, 51.43°,
102.86°, 154.29°, 205.71°, 257.15°, 308.57°
DELAY BLOCK
OUT4 (LVDS/CMOS) includes an analog delay element that
can be programmed (Register 34h to Register 36h) to give
variable time delays (T) in the clock signal passing through
that output.
05286-092
Δ
T
FINE DELAY ADJUST
(32 STEPS)
FULL-SCALE: 1ns TO 10ns
OUT4 ONLY
CLOCK INPUT
÷
N
∅SELECT
MUX
LVDS
CMOS OUTPUT
DRIVER
Figure 40. Analog Delay (OUT4)
The amount of delay that can be used is determined by the
frequency of the clock being delayed. The amount of delay can
approach one-half cycle of the clock period. For example, for a
10 MHz clock, the delay can extend to the full 10 ns maximum
of which the delay element is capable. However, for a 100 MHz
clock (with 50% duty cycle), the maximum delay is less than
5 ns (or half of the period).
OUT4 allows a full-scale delay in the range 1 ns to 10 ns. The
full-scale delay is selected by choosing a combination of ramp
current and the number of capacitors by writing the appropriate
values into Register 35h. There are 32 fine delay settings for
each full scale, set by Register 36h.
This path adds some jitter greater than that specified for the
nondelay outputs. This means that the delay function should be
used primarily for clocking digital chips, such as FPGA, ASIC,
DUC, and DDC, rather than for data converters. The jitter is
higher for long full scales (~10 ns). This is because the delay
block uses a ramp and trip points to create the variable delay. A
longer ramp means more noise may be introduced.
Calculating the Delay
The following values and equations are used to calculate the
delay of the delay block.
Value of Ramp Current Control Bits (Register 35h or Register 39h
<2:0>) = Iramp_bits
IRAMP (µA) = 200 × (Iramp_bits + 1)
No. of Caps = No. of 0s + 1 in Ramp Control Capacitor
(Register 35h or Register 39h <5:3>), that is, 101 = 1 + 1 = 2; 110
= 2; 100 = 2 + 1 = 3; 001 = 2 + 1 = 3; 111 = 0 + 1 = 1)
Delay_Range (ns) = 200 × [(No. of Caps + 3)/(IRAMP)] × 1.3286
()
()
6
1
1016000.34ns 4×
⎟
⎟
⎠
⎞
⎜
⎜
⎝
⎛−
+×−+= −
RAMP
RAMP I
CapsofNo.
IOffset
Delay_Full_Scale (ns) = Delay_Range + Offset
Fine_Adj = Value of Delay Fine Adjust (Register 36h or
Register 3Ah <5:1>), that is, 11111 = 31
Delay (ns) = Offset + Delay_Range × Fine_adj × (1/31)
OUTPUTS
The AD9511 offers three different output level choices:
LVPECL, LVDS, and CMOS. OUT0 to OUT2 are LVPECL only.
OUT3 and OUT4 can be selected as either LVDS or CMOS.
Each output can be enabled or turned off as needed to save
power.
The simplified equivalent circuit of the LVPECL outputs is
shown in Figure 41.
05286-037
3.3V
OUT
OUTB
GND
Figure 41. LVPECL Output Simplified Equivalent Circuit
AD9511
Rev. A | Page 39 of 60
05286-038
3
.5m
A
3
.5m
A
OUT
OUTB
Figure 42. LVDS Output Simplified Equivalent Circuit
POWER-DOWN MODES
Chip Power-Down or Sleep Mode—PDB
The PDB chip power-down turns off most of the functions and
currents in the AD9511. When the PDB mode is enabled, a chip
power-down is activated by taking the FUNCTION pin to a
logic low level. The chip remains in this power-down state until
PDB is brought back to logic high. When woken up, the
AD9511 returns to the settings programmed into its registers
prior to the power-down, unless the registers are changed by
new programming while the PDB mode is active.
The PDB power-down mode shuts down the currents on the
chip, except the bias current necessary to maintain the LVPECL
outputs in a safe shutdown mode. This is needed to protect the
LVPECL output circuitry from damage that could be caused by
certain termination and load configurations when tri-stated.
Because this is not a complete power-down, it can be called
sleep mode.
When the AD9511 is in a PDB power-down or sleep mode, the
chip is in the following state:
• The PLL is off (asynchronous power-down).
• All clocks and sync circuits are off.
• All dividers are off.
• All LVDS/CMOS outputs are off.
• All LVPECL outputs are in safe off mode.
• The serial control port is active, and the chip responds to
commands.
If the AD9511 clock outputs must be synchronized to each
other, a SYNC (see the Single-Chip Synchronization section) is
required upon exiting power-down mode.
PLL Power-Down
The PLL section of the AD9511 can be selectively powered
down. There are three PLL power-down modes, set by the
values in Register 0Ah<1:0>, as shown in Table 19.
Table 19. Register 0Ah: PLL Power-Down
<1> <0> Mode
0 0 Normal Operation
0 1 Asynchronous Power-Down
1 0 Normal Operation
1 1 Synchronous Power-Down
In asynchronous power-down mode, the device powers down as
soon as the registers are updated.
In synchronous power-down mode, the PLL power-down is
gated by the charge pump to prevent unwanted frequency
jumps. The device goes into power-down on the occurrence of
the next charge pump event after the registers are updated.
Distribution Power-Down
The distribution section can be powered down by writing to
Register 58h<3> = 1. This turns off the bias to the distribution
section. If the LVPECL power-down mode is normal operation
<00>, it is possible for a low impedance load on that LVPECL
output to draw significant current during this power-down. If
the LVPECL power-down mode is set to <11>, the LVPECL
output is not protected from reverse bias, and can be damaged
under certain termination conditions.
When combined with the PLL power-down, this mode results in
the lowest possible power-down current for the AD9511.
Individual Clock Output Power-Down
Any of the five clock distribution outputs can be powered down
individually by writing to the appropriate registers via the SCP.
The register map details the individual power-down settings for
each output. The LVDS/CMOS outputs may be powered down,
regardless of their output load configuration.
The LVPECL outputs have multiple power-down modes (see
Register 3Dh, Register 3Eh, and Register 3Fh in Table 24 ).
These give some flexibility in dealing with various output
termination conditions. When the mode is set to <10b>, the
LVPECL output is protected from reverse bias to 2 VBE + 1 V. If
the mode is set to <11b>, the LVPECL output is not protected
from reverse bias and can be damaged under certain
termination conditions. This setting also affects the operation
when the distribution block is powered down with Register
58h<3> = 1b (see the Distribution Power-Down section).
Individual Circuit Block Power-Down
Many of the AD9511 circuit blocks (CLK1, CLK2, and REFIN,
and so on) can be powered down individually. This gives
flexibility in configuring the part for power savings whenever
certain chip functions are not needed.
AD9511
Rev. A | Page 40 of 60
Synchronization of two or more AD9511s requires a fast clock
and a slow clock. The fast clock can be up to 1 GHz and may be
the clock driving the master AD9511 CLK1 input or one of the
outputs of the master. The fast clock acts as the input to the
distribution section of the slave AD9511 and is connected to its
CLK1 input. The PLL may be used on the master, but the slave
PLL is not used.
RESET MODES
The AD9511 has several ways to force the chip into a reset
condition.
Power-On Reset—Start-Up Conditions when VS is
Applied
A power-on reset (POR) is issued when the VS power supply is
turned on. This initializes the chip to the power-on conditions
that are determined by the default register settings. These are
indicated in the default value column of Tabl e 23 .
The slow clock is the clock that is synchronized across the two
chips. This clock must be no faster than one-fourth of the fast
clock, and no greater than 250 MHz. The slow clock is taken
from one of the outputs of the master AD9511 and acts as the
REFIN (or CLK2) input to the slave AD9511. One of the
outputs of the slave must provide this same frequency back to
the CLK2 (or REFIN) input of the slave.
Asynchronous Reset via the FUNCTION Pin
As mentioned in the FUNCTION Pin section, a hard reset,
RESETB: 58h<6:5> = 00b (Default), restores the chip to the
default settings.
Multichip synchronization is enabled by writing to Register
58h<0> = 1b on the slave AD9511. When this bit is set, the
STATUS pin becomes the output for the SYNC signal. A low
signal indicates an in-sync condition, and a high indicates an
out-of-sync condition.
Soft Reset via the Serial Port
The serial control port allows a soft reset by writing to
Register 00h<5> = 1b. When this bit is set, the chip executes a
soft reset. This restores the default values to the internal
registers, except for Register 00h itself.
Register 58h<1> selects the number of fast clock cycles that are
the maximum separation of the slow clock edges that are
considered synchronized. When 58h<1> = 0b (default), the
slow clock edges must be coincident within 1 to 1.5 high speed
clock cycles. If the coincidence of the slow clock edges is closer
than this amount, the SYNC flag stays low. If the coincidence of
the slow clock edges is greater than this amount, the SYNC flag
is set high. When Register 58h<1> = 1b, the amount of
coincidence required is 0.5 fast clock cycles to 1 fast clock
cycles.
This bit is not self-clearing. The bit must be written to
00h<5> = 0b for the operation of the part to continue.
SINGLE-CHIP SYNCHRONIZATION
SYNCB—Hardware SYNC
The AD9511 clocks can be synchronized to each other at any
time. The outputs of the clocks are forced into a known state
with respect to each other and then allowed to continue
clocking from that state in synchronicity. Before a
synchronization is done, the FUNCTION Pin must be set as the
SYNCB: 58h<6:5> = 01b input (58h<6:5> = 01b).
Synchronization is done by forcing the FUNCTION pin low,
creating a SYNCB signal and then releasing it.
Whenever the SYNC flag is set (high), indicating an out-of-sync
condition, a SYNCB signal applied simultaneously at the
FUNCTION pins of both AD9511s brings the slow clocks into
synchronization.
See the SYNCB: 58h<6:5> = 01b section for a more detailed
description of what happens when the SYNCB: 58h<6:5> = 01b
signal is issued.
05286-093
AD9511
MASTER FAST CLOCK
<1GHz
SLOW CLOCK
<250MHz
AD9511
SLAVE
FAST CLOCK
<1GHz
SLOW
CLOCK
<250MHz
SYNC
DETECT
CLK2 REFIN
OUTY
OUTM
OUTN
F
SYNC
F
SYNC
STATUS
(SYNC)
FUNCTION
(SYNCB)
FUNCTION
(SYNCB)
SYNCB
CLK1
Soft SYNC—Register 58h<2>
A soft SYNC may be issued by means of a bit in the Register
58h<2>. This soft SYNC works the same as the SYNCB, except
that the polarity is reversed. A 1 written to this bit forces the
clock outputs into a known state with respect to each other.
When a 0 is subsequently written to this bit, the clock outputs
continue clocking from that state in synchronicity.
MULTICHIP SYNCHRONIZATION
The AD9511 provides a means of synchronizing two or more
AD9511s. This is not an active synchronization; it requires user
monitoring and action. The arrangement of two AD9511s to be
synchronized is shown in Figure 43.
Figure 43. Multichip Synchronization
AD9511
Rev. A | Page 41 of 60
SERIAL CONTROL PORT
The AD9511 serial control port is a flexible, synchronous, serial
communications port that allows an easy interface with many
industry-standard microcontrollers and microprocessors. The
AD9511 serial control port is compatible with most
synchronous transfer formats, including both the Motorola SPI®
and Intel® SSR protocols. The serial control port allows
read/write access to all registers that configure the AD9511.
Single or multiple byte transfers are supported, as well as MSB
first or LSB first transfer formats. The AD9511 serial control
port can be configured for a single bidirectional I/O pin (SDIO
only) or for two unidirectional I/O pins (SDIO/SDO).
SERIAL CONTROL PORT PIN DESCRIPTIONS
SCLK (serial clock) is the serial shift clock. This pin is an input.
SCLK is used to synchronize serial control port reads and
writes. Write data bits are registered on the rising edge of this
clock, and read data bits are registered on the falling edge. This
pin is internally pulled down by a 30 kΩ resistor to ground.
SDIO (serial data input/output) is a dual-purpose pin and acts
as either an input only or as both an input/output. The AD9511
defaults to two unidirectional pins for I/O, with SDIO used as
an input and SDO as an output. Alternatively, SDIO can be used
as a bidirectional I/O pin by writing to the SDO enable register
at 00h<7> = 1b.
SDO (serial data out) is used only in the unidirectional I/O
mode (00h<7> = 0b, default) as a separate output pin for
reading back data. The AD9511 defaults to this I/O mode.
Bidirectional I/O mode (using SDIO as both input and output)
may be enabled by writing to the SDO enable register at
00h<7> = 1b.
CSB (chip select bar) is an active low control that gates the read
and write cycles. When CSB is high, SDO and SDIO are in a
high impedance state. This pin is internally pulled down by a
30 kΩ resistor to ground. It should not be left NC or tied low.
See the Framing a Communication Cycle with CSB section on
the use of the CSB in a communication cycle.
05286-094
SCLK (PIN 14)
SDIO (PIN 15)
SDO (PIN 16)
CSB (PIN 17)
AD9511
SERIAL
CONTROL
PORT
Figure 44. Serial Control Port
GENERAL OPERATION OF SERIAL CONTROL PORT
Framing a Communication Cycle with CSB
Each communication cycle (a write or a read operation) is gated
by the CSB line. CSB must be brought low to initiate a
communication cycle. CSB must be brought high at the
completion of a communication cycle (see Figure 52). If CSB is
not brought high at the end of each write or read cycle (on a
byte boundary), the last byte is not loaded into the register
buffer.
CSB stall high is supported in modes where three or fewer bytes
of data (plus instruction data) are transferred (W1:W0 must be
set to 00, 01, or 10, see Table 20). In these modes, CSB can
temporarily return high on any byte boundary, allowing time
for the system controller to process the next byte. CSB can go
high on byte boundaries only and can go high during either
part (instruction or data) of the transfer. During this period, the
serial control port state machine enters a wait state until all data
has been sent. If the system controller decides to abort the
transfer before all of the data is sent, the state machine must be
reset by either completing the remaining transfer or by
returning the CSB low for at least one complete SCLK cycle (but
less than eight SCLK cycles). Raising the CSB on a nonbyte
boundary terminates the serial transfer and flushes the buffer.
In the streaming mode (W1:W0 = 11b), any number of data
bytes can be transferred in a continuous stream. The register
address is automatically incremented or decremented (see the
MSB/LSB First Transfers section). CSB must be raised at the
end of the last byte to be transferred, thereby ending the
stream mode.
Communication Cycle—Instruction Plus Data
There are two parts to a communication cycle with the AD9511.
The first writes a 16-bit instruction word into the AD9511,
coincident with the first 16 SCLK rising edges. The instruction
word provides the AD9511 serial control port with information
regarding the data transfer, which is the second part of the
communication cycle. The instruction word defines whether
the upcoming data transfer is a read or a write, the number of
bytes in the data transferred, and the starting register address
for the first byte of the data transfer.
Write
If the instruction word is for a write operation (I15 = 0b), the
second part is the transfer of data into the serial control port
buffer of the AD9511. The length of the transfer (1, 2, 3 bytes or
streaming mode) is indicated by two bits (W1:W0) in the
instruction byte. CSB can be raised after each sequence of eight
bits to stall the bus (except after the last byte, where it ends the
cycle). When the bus is stalled, the serial transfer resumes when
CSB is lowered. Stalling on nonbyte boundaries resets the serial
control port.
Since data is written into a serial control port buffer area, not
directly into the AD9511’s actual control registers, an additional
operation is needed to transfer the serial control port buffer
contents to the actual control registers of the AD9511, thereby
causing them to take effect. This update command consists of
AD9511
Rev. A | Page 42 of 60
writing to Register 5Ah<0> = 1b. This update bit is self-clearing
(it is not required to write 0 to it to clear it). Since any number
of bytes of data can be changed before issuing an update
command, the update simultaneously enables all register
changes since any previous update.
Phase offsets or divider synchronization is not effective until a
SYNC is issued (see the Single-Chip Synchronization section).
Read
If the instruction word is for a read operation (I15 = 1b), the
next N × 8 SCLK cycles clock out the data from the address
specified in the instruction word, where N is 1 to 4 as
determined by W1:W0. The readback data is valid on the falling
edge of SCLK.
The default mode of the AD9511 serial control port is
unidirectional mode; therefore, the requested data appears on
the SDO pin. It is possible to set the AD9511 to bidirectional
mode by writing the SDO enable register at 00h<7> = 1b. In
bidirectional mode, the readback data appears on the SDIO pin.
A readback request reads the data that is in the serial control
port buffer area, not the active data in the AD9511’s actual
control registers.
05286-095
S
CL
K
SDIO
SDO
CSB UPDATE
REGISTERS
5Ah <0>
SERIAL
CONTROL
PORT
REGISTER BUFFERS
AD9511
CORE
CONTROL REGISTERS
Figure 45. Relationship Between Serial Control Port Register Buffers and
Control Registers of the AD9511
The AD9511 uses Address 00h to Address 5Ah. Although the
AD9511 serial control port allows both 8-bit and 16-bit
instructions, the 8-bit instruction mode provides access to five
address bits (A4 to A0) only, which restricts its use to the
address space 00h to 01F. The AD9511 defaults to 16-bit
instruction mode on power-up. The 8-bit instruction mode
(although defined for this serial control port) is not useful for
the AD9511; therefore, it is not discussed further in this data
sheet.
THE INSTRUCTION WORD (16 BITS)
The MSB of the instruction word is R/W, which indicates
whether the instruction is a read or a write. The next two bits,
W1:W0, indicate the length of the transfer in bytes. The final 13
bits are the addresses (A12:A0) at which to begin the read or
write operation.
For a write, the instruction word is followed by the number of
bytes of data indicated by Bits W1:W0, which is interpreted
according to Table 2 0.
Table 20. Byte Transfer Count
W1 W0 Bytes to Transfer
0 0 1
0 1 2
1 0 3
1 1 4
A12:A0: These 13 bits select the address within the register map
that is written to or read from during the data transfer portion
of the communications cycle. The AD9511 does not use all of
the 13-bit address space. Only Bits A6:A0 are needed to cover
the range of the 5Ah registers used by the AD9511. Bits A12:A7
must always be 0b. For multibyte transfers, this address is the
starting byte address. In MSB first mode, subsequent bytes
increment the address.
MSB/LSB FIRST TRANSFERS
The AD9511 instruction word and byte data may be MSB first
or LSB first. The default for the AD9511 is MSB first. The LSB
first mode may be set by writing 1b to Register 00h<6>. This
takes effect immediately (since it only affects the operation of
the serial control port) and does not require that an update be
executed. Immediately after the LSB first bit is set, all serial
control port operations are changed to LSB first order.
When MSB first mode is active, the instruction and data bytes
must be written from MSB to LSB. Multibyte data transfers in
MSB first format start with an instruction byte that includes the
register address of the most significant data byte. Subsequent
data bytes must follow in order from high address to low
address. In MSB first mode, the serial control port internal
address generator decrements for each data byte of the
multibyte transfer cycle.
When LSB_First = 1b (LSB first), the instruction and data bytes
must be written from LSB to MSB. Multibyte data transfers in
LSB first format start with an instruction byte that includes the
register address of the least significant data byte followed by
multiple data bytes. The serial control port internal byte address
generator increments for each byte of the multibyte transfer
cycle.
The AD9511 serial control port register address decrements
from the register address just written toward 0000h for
multibyte I/O operations if the MSB first mode is active
(default). If the LSB first mode is active, the serial control port
register address increments from the address just written
toward 1FFFh for multibyte I/O operations.
Unused addresses are not skipped during multibyte I/O
operations; therefore, it is important to avoid multibyte I/O
operations that would include these addresses.
AD9511
Rev. A | Page 43 of 60
Table 21. Serial Control Port, 16-Bit Instruction Word, MSB First
MSB LSB
I15 I14 I13 I12 I11 I10 I9 I8 I7 I6 I5 I4 I3 I2 I1 I0
R/WW1 W0 A12 = 0 A11 = 0 A10 = 0 A9 = 0 A8 = 0 A7 = 0 A6 A5 A4 A3 A2 A1 A0
05286-019
CSB
SCLK
DON'T CARE
SDIO A12W0W1R/W A11 A10 A9 A8 A7 A6 A5 A4 A3 A2 A1 A0 D7 D6 D5 D4 D3 D2 D1 D0 D7 D6 D5 D4 D3 D2 D1 D0 DON'T CARE
DON'T CARE
DON'T CARE
16-BIT INSTRUCTION HEADER REGISTER (N) DATA REGISTER (N – 1) DATA
Figure 46. Serial Control Port Write—MSB First, 16-Bit Instruction, 2 Bytes of Data
05286-020
CSB
SCLK
SDIO
SDO
REGISTER (N) DATA16-BIT INSTRUCTION HEADER REGISTER (N – 1) DATA REGISTER (N – 2) DATA REGISTER (N – 3) DATA
A12W0W1R/W A11A10 A9 A8 A7 A6 A5 A4 A3 A2 A1 A0
DON'T CARE
DON'T CARE
DON'T CARE
DON'T
CARE
D7 D6 D5 D4 D3 D2 D1 D0 D7 D6 D5 D4 D3 D2 D1 D0 D7 D6 D5 D4 D3 D2 D1 D0 D7 D6 D5 D4 D3 D2 D1 D0
Figure 47. Serial Control Port Read—MSB First, 16-Bit Instruction, 4 Bytes od Data
05286-021
t
S
DON'T CARE
DON'T CARE W1 W0 A12 A11 A10 A9 A8 A7 A6 A5 D4 D3 D2 D1 D0
DON'T CARE
DON'T CARE
R/W
t
DS
t
DH
t
HI
t
LO
t
CLK
t
H
CSB
SCLK
SDIO
Figure 48. Serial Control Port Write—MSB First, 16-Bit Instruction, Timing Measurements
05286-022
DATA BI T N– 1DATA BIT N
CSB
SCL
K
SDIO
SDO
t
DV
Figure 49. Timing Diagram for Serial Control Port Register Read
05286-023
CSB
SCLK DON'T CARE DON'T CARE
16-BIT INSTRUCTION HEADER REGISTER (N) DATA REGISTER (N + 1) DATA
SDIO DON'T CARE
DON'T CARE A0 A1 A2 A3 A4 A5 A6 A7 A8 A9 A10 A11 A12 D1D0R/WW1W0 D2 D3 D4 D5 D6 D7 D0 D1 D2 D3 D4 D5 D6 D7
Figure 50. Serial Control Port Write—LSB First, 16-Bit Instruction, 2 Bytes Data
AD9511
Rev. A | Page 44 of 60
05286-040
CSB
SCLK
SDIO
t
HI
t
LO
t
CLK
t
S
t
DS
t
DH
t
H
BI N BI N + 1
Figure 51. Serial Control Port Timing—Write
Table 22. Serial Control Port Timing
Parameter Description
tDS Setup time between data and rising edge of SCLK
tDH Hold time between data and rising edge of SCLK
tCLK Period of the clock
tSSetup time between CSB and SCLK
tHHold time between CSB and SCLK
tHI Minimum period that SCLK should be in a logic high state
tLO Minimum period that SCLK should be in a logic low state
05286-067
CSB
CSB TOGGLE INDIC
A
TES
CYCLE CO MP LE T E
16 INS T RUCTION BITS + 8 DATA BITS 16 INSTRUCT ION BIT S + 8 DATA BITS
CO MM U NIC ATION CY CLE 1 CO MMUNI CAT I ON CY CLE 2
TIMING DIAGRAM FOR TWO S UCCES SIVE COMMUNI CATION CYCL E S. NO TE THAT CSB MUST
BE TOGG LED HIG H AND THEN LO W AT THE COMP L ETION OF A COMMUNICATIO N CYCL E.
t
PWH
SCLK
SDIO
Figure 52. Use of CSB to Define Communications Cycles
AD9511
Rev. A | Page 45 of 60
REGISTER MAP AND DESCRIPTION
SUMMARY TABLE
Table 23. AD9511 Register Map
Addr
(Hex) Parameter Bit 7 (MSB) Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1
Bit 0
(LSB)
Def.
Value
(Hex) Notes
00 Serial
Control Port
Configuration
SDO Inactive
(Bidirectional
Mode)
LSB
First
Soft
Reset
Long
Instruction
Not Used 10
01,
02,
03
Not Used
PLL
PLL Starts
in Power-
Down
04 A Counter Not Used 6-Bit A Counter <5:0> 00 N Divider
(A)
05 B Counter Not Used 13-Bit B Counter Bits 12:8 (MSB) <4:0> 00 N Divider
(B)
06 B Counter 13-Bit B Counter Bits 7:0 (LSB) <7:0> 00 N Divider
(B)
07 PLL 1 Not
Used
LOR Lock_Del
<6:5>
Not Used LOR
Enable
Not Used 00
08 PLL 2 Not
Used
PFD
Polarity
PLL Mux Select <5:2>
Signal on STATUS pin
CP Mode <1:0> 00
09 PLL 3 Not
Used
CP Current <6:4> Not
Used
Reset R
Counter
Reset N
Counter
Reset All
Counters
00
0A PLL 4 Not
Used
B
Bypass
Not
Used
Prescaler P <4:2> Power-Down <1:0> 01 N Divider
(P)
0B R Divider Not Used 14-Bit R Divider Bits 13:8 (MSB) <5:0> 00 R Divider
0C R Divider 14-Bit R Divider Bits 13:8 (MSB) <7:0> 00 R Divider
0D PLL 5 Not
Used
Digital
Lock
Det
Enable
Digital
Lock
Det
Window
Not Used Antibacklash
Pulse Width <1:0>
00
OE-
33
Not Used
FINE DELAY
ADJUST
Fine
Delays
Bypassed
34 Delay Bypass 4 Not Used Bypass 01 Bypass
Delay
35 Delay
Full-Scale 4
Not Used Ramp Capacitor <5:3> Ramp Current <2:0> 00 Max.
Delay
Full-Scale
36 Delay Fine
Adjust 4
Not Used 5-Bit Fine Delay <5:1> Not
Used
00 Min. Delay
Value
37,
38,
39,
3A,
3B,
3C
Not Used
AD9511
Rev. A | Page 46 of 60
Addr
(Hex) Parameter Bit 7 (MSB) Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1
Bit 0
(LSB)
Def.
Value
(Hex) Notes
OUTPUTS
3D LVPECL OUT0 Not Used Output Level
<3:2>
Power-Down <1:0> 08 ON
3E LVPECL OUT1 Not Used Output Level
<3:2>
Power-Down <1:0> 08 ON
3F LVPECL OUT2 Not Used Output Level
<3:2>
Power-Down <1:0> 08 ON
40 LVDS_CMOS
OUT 3
Not Used CMOS
Inverted
Driver On
Logic
Select
Output Level
<2:1>
Output
Power
02 LVDS, ON
41 LVDS_CMOS
OUT 4
Not Used CMOS
Inverted
Driver On
Logic
Select
Output Level
<2:1>
Output
Power
02 LVDS, ON
42,
43,
44
Not Used
CLK1 AND
CLK2
Input
Receivers
45 Clocks Select,
Power-Down
(PD) Options
Not Used CLKs in
PD
REFIN PD CLK
to
PLL
PD
CLK2
PD
CLK1
PD
Select
CLK IN
01 All Clocks
ON, Select
CLK1
46,
47,
48, 49
Not Used
DIVIDERS
4A Divider 0 Low Cycles <7:4> High Cycles <3:0> 00 Divide by 2
4B Divider 0 Bypass No
Sync
Force Start H/L Phase Offset <3:0> 00 Phase = 0
4C Divider 1 Low Cycles <7:4> High Cycles <3:0> 11 Divide by 4
4D Divider 1 Bypass No
Sync
Force Start H/L Phase Offset <3:0> 00 Phase = 0
4E Divider 2 Low Cycles <7:4> High Cycles <3:0> 33 Divide by 8
4F Divider 2 Bypass No
Sync
Force Start H/L Phase Offset <3:0> 00 Phase = 0
50 Divider 3 Low Cycles <7:4> High Cycles <3:0> 00 Divide by 2
51 Divider 3 Bypass No
Sync
Force Start H/L Phase Offset <3:0> 00 Phase = 0
52 Divider 4 Low Cycles <7:4> High Cycles <3:0> 11 Divide by 4
53 Divider 4 Bypass No
Sync
Force Start H/L Phase Offset <3:0> 00 Phase = 0
54,
55,
56,
57
Not Used
FUNCTION
58 FUNCTION
Pin and Sync
Not
Used
Set FUNCTION Pin PD Sync PD All
Ref
Sync
Reg
Sync
Select
Sync
Enable
00 FUNCTION
Pin =
RESETB
59 Not Used
5A Update
Registers
Not Used Update
Registers
00 Self-
Clearing
Bit
END
AD9511
Rev. A | Page 47 of 60
REGISTER MAP DESCRIPTION
Table 24 lists the AD9511 control registers by hexadecimal address. A specific bit or range of bits within a register is indicated by angle
brackets. For example, <3> refers to Bit 3, while <5:2> refers to the range of bits from Bit 5 through Bit 2. Table 24 describes the
functionality of the control registers on a bit-by-bit basis. For a more concise (but less descriptive) table, see Table 23.
Table 24. AD9511 Register Descriptions
Reg.
Addr.
(Hex) Bit(s) Name Description
Serial Control Port
Configuration
Any changes to this register takes effect immediately. Register 5Ah<0> Update Registers does not
have to be written.
00 <3:0> Not Used.
00 <4> Long Instruction
When this bit is set (1), the instruction phase is 16 bits. When clear (0), the instruction phase is 8 bits.
The default, and only, mode for this part is long instruction (Default = 1b).
00 <5> Soft Reset
When this bit is set (1), the chip executes a soft reset, restoring default values to the internal
registers, except for this register, 00h. This bit is not self-clearing. A clear (0) has to be written
to it to clear it.
00 <6> LSB First When this bit is set (1), the input and output data is oriented as LSB first. Additionally, register
addressing increments. If this bit is clear (0), data is oriented as MSB first and register addressing
decrements. (Default = 0b, MSB first).
00 <7>
SDO Inactive
(Bidirectional
Mode)
When set (1), the SDO pin is tri-state and all read data goes to the SDIO pin. When clear (0), the
SDO is active (unidirectional mode). (Default = 0b).
Not Used
01 <7:0> Not Used.
02 <7:0> Not Used.
03 <7:0> Not Used.
PLL Settings
04 <5:0> A Counter 6-Bit A Counter <5:0>.
04 <7:6> Not Used.
05 <4:0> B Counter MSBs 13-Bit B Counter (MSB) <12:8>.
05 <7:5> Not Used.
06 <7:0> B Counter LSBs 13-Bit B Counter (LSB) <7:0>.
07 <1:0> Not Used.
07 <2> LOR Enable 1 = Enables the Loss-of-Reference (LOR) Function; (Default = 0b).
07 <4:3> Not Used.
07 <6:5>
LOR Initial Lock
Detect Delay
LOR Initial Lock Detect Delay. Once a lock detect is indicated, this is the number of phase frequency
detector (PFD) cycles that occur prior to turning on the LOR monitor.
<6> <5> LOR Initial Lock Detect Delay
0 0 3 PFD Cycles (Default)
0 1 6 PFD Cycles
1 0 12 PFD Cycles
1 1 24 PFD Cycles
07 <7> Not Used
08 <1:0>
Charge Pump
Mode
<1> <0> Charge Pump Mode
0 0 Tri-Stated (Default)
0 1 Pump-Up
1 0 Pump-Down
1 1 Normal Operation
AD9511
Rev. A | Page 48 of 60
Reg.
Addr.
(Hex) Bit(s) Name Description
08 <5:2> PLL Mux Control
<5> <4> <3> <2> MUXOUT—Signal on STATUS Pin
0 0 0 0 Off (Signal Goes Low) (Default)
0 0 0 1 Digital Lock Detect (Active High)
0 0 1 0 N Divider Output
0 0 1 1 Digital Lock Detect (Active Low)
0 1 0 0 R Divider Output
0 1 0 1 Analog Lock Detect (N Channel, Open-Drain)
0 1 1 0 A Counter Output
0 1 1 1 Prescaler Output (NCLK)
1 0 0 0 PFD Up Pulse
1 0 0 1 PFD Down Pulse
1 0 1 0 Loss-of-Reference (Active High)
1 0 1 1 Tri-State
1 1 0 0 Analog Lock Detect (P Channel, Open-Drain)
1 1 0 1
Loss-of-Reference or Loss-of-Lock (Inverse of DLD)
(Active High)
1 1 1 0
Loss-of-Reference or Loss-of-Lock (Inverse of DLD)
(Active Low)
1 1 1 1 Loss-of-Reference (Active Low)
MUXOUT is the PLL portion of the STATUS output MUX.
08 <6>
Phase-Frequency
Detector (PFD)
Polarity
0 = Negative (Default), 1 = Positive.
08 <7> Not Used.
09 <0> Reset All Counters 0 = Normal (Default), 1 = Reset R, A, and B Counters.
09 <1> N-Counter Reset 0 = Normal (Default), 1 = Reset A and B Counters.
09 <2> R-Counter Reset 0 = Normal (Default), 1 = Reset R Counter.
09 <3> Not Used.
09 <6:4>
Charge Pump (CP)
Current Setting
<6> <5> <4> ICP (mA)
0 0 0 0.60
0 0 1 1.2
0 1 0 1.8
0 1 1 2.4
1 0 0 3.0
1 0 1 3.6
1 1 0 4.2
1 1 1 4.8
Default = 000b.
These currents assume: CPRSET = 5.1 kΩ.
Actual current can be calculated by: CP_lsb = 3.06/CPRSET.
09 <7> Not Used.
AD9511
Rev. A | Page 49 of 60
Reg.
Addr.
(Hex) Bit(s) Name Description
0A <1:0> PLL Power-Down 01 = Asynchronous Power-Down (Default).
<1> <0> Mode
0 0 Normal Operation
0 1 Asynchronous Power-Down
1 0 Normal Operation
1 1 Synchronous Power-Down
0A <4:2>
Prescaler Value
(P/P+1)
<4> <3> <2> Mode Prescaler Mode
0 0 0 FD Divide by 1
0 0 1 FD Divide by 2
0 1 0 DM 2/3
0 1 1 DM 4/5
1 0 0 DM 8/9
1 0 1 DM 16/17
1 1 0 DM 32/33
1 1 1 FD Divide by 3
DM = Dual Modulus, FD = Fixed Divide.
0A <5> Not Used.
0A <6> B Counter Bypass Only valid when operating the prescaler in fixed divide (FD) mode. When this bit is set, the
B counter is divided by 1. This allows the prescaler setting to determine the divide for the
N divider.
0A <7> Not Used.
0B <5:0>
14-Bit Reference
Counter, MSBs
R Divider (MSB) <13:8>.
0C <7:0>
14-Bit Reference
Counter, R LSBs
R Divider (MSB) <7:0>.
0D <1:0>
Antibacklash
Pulse-Width
<1> <0> Antibacklash Pulse Width (ns)
0 0 1.3 (Default)
0 1 2.9
1 0 6.0
1 1 1.3
0D <4:2> Not Used.
0D <5>
Digital Lock
Detect Window
<5> Digital Lock Detect Window (ns) Digital Lock Detect Loss-of-Lock Threshold (ns)
0 (Default) 9.5 15
1 3.5 7
Digital Lock
Detect Window
If the time difference of the rising edges at the inputs to the PFD are less than the lock detect
window time, the digital lock detect flag is set. The flag remains set until the time difference is
greater than the loss-of-lock threshold.
0D <6>
Lock Detect
Disable
0 = Normal Lock Detect Operation (Default).
1 = Disable Lock Detect.
0D <7> Not Used.
Unused
0E-33 Not Used.
AD9511
Rev. A | Page 50 of 60
Reg.
Addr.
(Hex) Bit(s) Name Description
Fine Delay Adjust
34 <0>
Delay Control
OUT4
Delay Block Control Bit.
Bypasses Delay Block and Powers It Down (Default = 1b).
34 <7:1> Not Used.
35 <2:0>
Ramp Current
OUT4
The slowest ramp (200 µs) sets the longest full scale of approximately 10 ns.
<2> <1> <0> Ramp Current (μs)
0 0 0 200
0 0 1 400
0 1 0 600
0 1 1 800
1 0 0 1000
1 0 1 1200
1 1 0 1400
1 1 1 1600
35 <5:3>
Ramp Capacitor
OUT4
Selects the Number of Capacitors in Ramp Generation Circuit.
More Capacitors => Slower Ramp.
<5> <4> <3> Number of Capacitors
0 0 0 4 (Default)
0 0 1 3
0 1 0 3
0 1 1 2
1 0 0 3
1 0 1 2
1 1 0 2
1 1 1 1
35 <7:6> Not Used.
36 <0> Not Used.
36 <5:1>
Delay Fine Adjust
OUT4
Sets Delay Within Full Scale of the Ramp; There Are 32 Steps.
00000b => Zero Delay (Default).
11111b => Maximum Delay.
36 <7:6> Not Used.
37 (38) (39)
(3A) (3B)
(3C)
<7:0> Not Used.
Power-Down
LVPECL
OUT0
(OUT1)
(OUT2)
3D (3E) (3F) <1:0>
Mode <1> <0> Description Output
ON 0 0 Normal Operation ON
PD1 0 1 Test Only—Do Not Use OFF
PD2 1 0
Safe Power-Down
Partial Power-Down; Use If
Output Has Load Resistors
OFF
PD3 1 1
Total Power-Down
Use Only If Output Has No
Load Resistors
OFF
AD9511
Rev. A | Page 51 of 60
Reg.
Addr.
(Hex) Bit(s) Name Description
Output Level
LVPECL
OUT0
(OUT1)
(OUT2)
Output Single-Ended Voltage Levels for LVPECL Outputs.
3D (3E) (3F) <3:2>
<3> <2> Output Voltage (mV)
0 0 490
0 1 330
1 0 805 (Default)
1 1 650
3D (3E) (3F) <7:4> Not Used
40 (41) <0> Power-Down
LVDS/CMOS
OUT3
(OUT4)
Power-Down Bit for Both Output and LVDS Driver.
0 = LVDS/CMOS on (Default).
1 = LVDS/CMOS Power-Down.
Output Current
Level
LVDS
OUT3
(OUT4)
40 (41) <2:1>
<2> <1> Current (mA) Termination (Ω)
0 0 1.75 100
0 1 3.5 (Default) 100
1 0 5.25 50
1 1 7 50
40 (41) <3> LVDS/CMOS
Select
OUT3
(OUT4)
0 = LVDS (Default).
1 = CMOS.
40 (41) <4> Inverted CMOS
Driver
OUT3
(OUT4)
Affects Output Only when in CMOS Mode.
0 = Disable Inverted CMOS Driver (Default).
1 = Enable Inverted CMOS Driver.
40 (41) <7:5> Not Used.
42 (43) (44) <7:0> Not Used.
45 <0> Clock Select
0: CLK2 Drives Distribution Section.
1: CLK1 Drives Distribution Section (Default).
45 <1> CLK1 Power-Down 1 = CLK1 Input Is Powered Down (Default = 0b).
45 <2> CLK2 Power-Down 1 = CLK2 Input Is Powered Down (Default = 0b).
45 <3>
Prescaler Clock
Power-Down
1 = Shut Down Clock Signal to PLL Prescaler (Default = 0b).
45 <4>
REFIN Power-
Down
1 = Power-Down REFIN (Default = 0b).
45 <5>
All Clock Inputs
Power-Down
1 = Power-Down CLK1 and CLK2 Inputs and Associated Bias and Internal Clock Tree;
(Default = 0b).
45 <7:6> Not Used.
46 (47)
(48) (49)
<7:0> Not Used.
AD9511
Rev. A | Page 52 of 60
Reg.
Addr.
(Hex) Bit(s) Name Description
<3:0> Divider High Number of Clock Cycles Divider Output Stays High.
4A OUT0
(4C) (OUT1)
(4E) (OUT2)
(50) (OUT3)
(52) (OUT4)
<7:4> Divider Low Number of Clock Cycles Divider Output Stays Low.
4A OUT0
(4C) (OUT1)
(4E) (OUT2)
(50) (OUT3)
(52) (OUT4)
<3:0> Phase Offset Phase Offset (Default = 0000b).
4B OUT0
(4D) (OUT1)
(4F) (OUT2)
(51) (OUT3)
(53) (OUT4)
<4> Start Selects Start High or Start Low.
4B OUT0 (Default = 0b).
(4D) (OUT1)
(4F) (OUT2)
(51) (OUT3)
(53) (OUT4)
<5> Force Forces Individual Outputs to the State Specified in Start (Above).
This Function Requires That Nosync (Below) Also Be Set (Default = 0b).
4B OUT0
(4D) (OUT1)
(4F) (OUT2)
(51) (OUT3)
(53) (OUT4)
<6> Nosync Ignore Chip-Level Sync Signal (Default = 0b).
4B OUT0
(4D) (OUT1)
(4F) (OUT2)
(51) (OUT3)
(53) (OUT4)
<7> Bypass Divider Bypass and Power-Down Divider Logic; Route Clock Directly to Output (Default = 0b).
4B OUT0
(4D) (OUT1)
(4F) (OUT2)
(51) (OUT3)
(53) (OUT4)
54 (55)
(56) (57)
<7:0> Not Used.
58 <0>
SYNC Detect
Enable
1 = Enable SYNC Detect (Default = 0b).
58 <1> SYNC Select
1 = Raise Flag if Slow Clocks Are Out-of-Sync by 0.5 to 1 High Speed Clock Cycles.
0 (Default) = Raise Flag if Slow Clocks Are Out-of-Sync by 1 to 1.5 High Speed Clock Cycles.
AD9511
Rev. A | Page 53 of 60
Reg.
Addr.
(Hex) Bit(s) Name Description
58 <2> Soft SYNC
Soft SYNC bit works the same as the FUNCTION pin when in SYNCB mode, except that this bit’s
polarity is reversed. That is, a high level forces selected outputs into a known state, and a high > low
transition triggers a sync (Default = 0b).
58 <3>
Dist Ref Power-
Down
1 = Power-Down the References for the Distribution Section (Default = 0b).
58 <4>
SYNC Power-
Down
1 = Power-Down the SYNC (Default = 0b).
<6> <5> Function
0 0 RESETB (Default)
0 1 SYNCB
1 0 Test Only; Do Not Use
58 <6:5>
FUNCTION Pin
Select
1 1 PDB
58 <7> Not Used
59 <7:0> Not Used
5A <0> Update Registers
1 written to this bit updates all registers and transfers all serial control port register buffer contents
to the control registers on the next rising SCLK edge. This is a self-clearing bit. 0 does not have to be
written to clear it.
5A <7:1> Not Used.
END
AD9511
Rev. A | Page 54 of 60
POWER SUPPLY
The AD9511 requires a 3.3 V ± 5% power supply for VS.
The tables in the Specifications section give the performance
expected from the AD9511 with the power supply voltage
within this range. The absolute maximum range of −0.3 V to
+3.6 V, with respect to GND, must never be exceeded on
the VS pin.
Good engineering practice should be followed in the layout of
power supply traces and ground plane of the PCB. The power
supply should be bypassed on the PCB with adequate
capacitance (>10 F). The AD9511 should be bypassed with
adequate capacitors (0.1 F) at all power pins, as close as
possible to the part. The layout of the AD9511 evaluation board
(AD9511/PCB or AD9511-VCO/PCB) is a good example.
The AD9511 is a complex part that is programmed for its
desired operating configuration by on-chip registers. These
registers are not maintained over a shutdown of external power.
This means that the registers can lose their programmed values
if VS is lost long enough for the internal voltages to collapse.
Careful bypassing should protect the part from memory loss
under normal conditions. Nonetheless, it is important that the
VS power supply not become intermittent, or the AD9511 risks
losing its programming.
The internal bias currents of the AD9511 are set by the RSET and
CPRSET resistors. These resistors should be as close as possible to
the values given as conditions in the Specifications section
(RSET = 4.12 kΩ and CPRSET = 5.1 kΩ). These values are standard
1% resistor values and should be readily obtainable. The bias
currents set by these resistors determine the logic levels and
operating conditions of the internal blocks of the AD9511. The
performance figures given in the Specifications section assume
that these resistor values are used.
The VCP pin is the supply pin for the charge pump (CP). The
voltage at this pin (VCP) may be from VS up to 5.5 V, as required
to match the tuning voltage range of a specific VCO/VCXO.
This voltage must never exceed the absolute maximum of 6 V.
VCP should also never be allowed to be less than −0.3 V below
VS or GND, whichever is lower.
The exposed metal paddle on the AD9511 package is an
electrical connection, as well as a thermal enhancement. For
the device to function properly, the paddle must be properly
attached to ground (GND). The PCB acts as a heat sink for the
AD9511; therefore, this GND connection should provide a
good thermal path to a larger dissipation area, such as a ground
plane on the PCB. See the layout of the AD9511 evaluation
board (AD9511/PCB or AD9511-VCO/PCB) for a good
example.
POWER MANAGEMENT
The power usage of the AD9511 can be managed to use only the
power required for the functions that are being used. Unused
features and circuitry can be powered down to save power. The
following circuit blocks can be powered down, or are powered
down when not selected (see the Register Map and Description
section):
• The PLL section can be powered down if not needed.
• Any of the dividers are powered down when bypassed—
equivalent to divide-by-one.
• The adjustable delay block on OUT4 is powered down
when not selected.
• Any output may be powered down. However, LVPECL
outputs have both a safe and an off condition. When the
LVPECL output is terminated, only the safe shutdown
should be used to protect the LVPECL output devices. This
still consumes some power.
• The entire distribution section can be powered down when
not needed.
Powering down a functional block does not cause the
programming information for that block (in the registers) to be
lost. This means that blocks can be powered on and off without
otherwise having to reprogram the AD9511. However,
synchronization is lost. A SYNC must be issued to
resynchronize (see the Single-Chip Synchronization section).
AD9511
Rev. A | Page 55 of 60
APPLICATIONS
USING THE AD9511 OUTPUTS FOR ADC CLOCK
APPLICATIONS
Any high speed analog-to-digital converter (ADC) is extremely
sensitive to the quality of the sampling clock provided by the
user. An ADC can be thought of as a sampling mixer; any noise,
distortion, or timing jitter on the clock is combined with the
desired signal at the A/D output. Clock integrity requirements
scale with the analog input frequency and resolution, with
higher analog input frequency applications at ≥14-bit resolution
being the most stringent. The theoretical SNR of an ADC is
limited by the ADC resolution and the jitter on the sampling
clock. Considering an ideal ADC of infinite resolution where
the step size and quantization error can be ignored, the available
SNR can be expressed approximately by
⎥
⎥
⎦
⎤
⎢
⎢
⎣
⎡
×=
j
ft
SNR 2π
1
log20
where f is the highest analog frequency being digitized, and tj is
the rms jitter on the sampling clock. Figure 53 shows the
required sampling clock jitter as a function of the analog
frequency and effective number of bits (ENOB).
120
100
80
60
40
20 4
6
8
10
12
14
16
18
1 3 10 30 100
05286-024
FULL-SCALE SINE WAVE ANALOG INPUT FREQUENCY (MHz)
SNR (dB)
ENOB
tj = 50fs
tj = 0.1ps
tj = 1ps
tj = 10ps
tj = 100ps
tj = 1ns
SNR = 20log10 1
2πftj
Figure 53. ENOB and SNR vs. Analog Input Frequency
See Application Notes AN-756 and AN-501 on the ADI website
at www.analog.com.
Many high performance ADCs feature differential clock inputs
to simplify the task of providing the required low jitter clock on
a noisy PCB. (Distributing a single-ended clock on a noisy PCB
can result in coupled noise on the sample clock. Differential
distribution has inherent common-mode rejection, which can
provide superior clock performance in a noisy environment.)
The AD9511 features both LVPECL and LVDS outputs that
provide differential clock outputs, which enable clock solutions
that maximize converter SNR performance. The input
requirements of the ADC (differential or single-ended, logic
level, termination) should be considered when selecting the best
clocking/converter solution.
CMOS CLOCK DISTRIBUTION
The AD9511 provides two clock outputs (OUT3 and OUT4),
which are selectable as either CMOS or LVDS levels. When
selected as CMOS, these outputs provide for driving devices
requiring CMOS level logic at their clock inputs.
Whenever single-ended CMOS clocking is used, some of the
following general guidelines should be followed.
Point-to-point nets should be designed such that a driver has
one receiver only on the net, if possible. This allows for simple
termination schemes and minimizes ringing due to possible
mismatched impedances on the net. Series termination at the
source is generally required to provide transmission line
matching and/or to reduce current transients at the driver. The
value of the resistor is dependent on the board design and
timing requirements (typically 10 Ω to 100 Ω is used). CMOS
outputs are limited in terms of the capacitive load or trace
length that they can drive. Typically, trace lengths less than
3 inches are recommended to preserve signal rise/fall times and
preserve signal integrity.
05286-096
10Ω
MICROSTRIP
GND
50pF
60.4Ω
1.0 INCH
CMOS
Figure 54. Series Termination of CMOS Output
Termination at the far end of the PCB trace is a second option.
The CMOS outputs of the AD9511 do not supply enough
current to provide a full voltage swing with a low impedance
resistive, far-end termination, as shown in Figure 55. The far-
end termination network should match the PCB trace
impedance and provide the desired switching point. The
reduced signal swing can still meet receiver input requirements
in some applications. This may be useful when driving long
trace lengths on less critical nets.
05286-097
50Ω
10Ω
OUT3, OUT4
SELECTED AS CMOS
V
PULLUP
= 3.3V
CMOS 3pF
100Ω
100Ω
Figure 55. CMOS Output with Far-End Termination
AD9511
Rev. A | Page 56 of 60
Because of the limitations of single-ended CMOS clocking,
consider using differential outputs when driving high speed
signals over long traces. The AD9511 offers both LVPECL and
LVDS outputs, which are better suited for driving long traces
where the inherent noise immunity of differential signaling
provides superior performance for clocking converters.
LVDS CLOCK DISTRIBUTION
Low voltage differential signaling (LVDS) is a second
differential output option for the AD9511. LVDS uses a current
mode output stage with several user-selectable current levels.
The normal value (default) for this current is 3.5 mA, which
yields 350 mV output swing across a 100 Ω resistor. The LVDS
outputs meet or exceed all ANSI/TIA/EIA—644 specifications.
LVPECL CLOCK DISTRIBUTION
The low voltage, positive emitter-coupled, logic (LVPECL)
outputs of the AD9511 provide the lowest jitter clock signals
available from the AD9511. The LVPECL outputs (because they
are open emitter) require a dc termination to bias the output
transistors. A simplified equivalent circuit in
A recommended termination circuit for the LVDS outputs is
shown in Figure 58.
05286-032
3.3V
LVDS 100Ω
DIFFERENTIAL (COUPLED)
3.3V
LVDS
100Ω
Figure 41 shows
the LVPECL output stage.
In most applications, a standard LVPECL far-end termination is
recommended, as shown in Figure 56. The resistor network is
designed to match the transmission line impedance (50 Ω) and
the desired switching threshold (1.3 V).
Figure 58. LVDS Output Termination
05286-030
3.3V
LVPECL
50Ω
50Ω
SINGLE-ENDED
(NOT COUPLED)
3.3V
3.3V
LVPECL
127Ω127Ω
83Ω83Ω
VT = VCC – 1.3V
See Application Note AN-586 on the ADI website at
www.analog.com for more information on LVDS.
POWER AND GROUNDING CONSIDERATIONS AND
POWER SUPPLY REJECTION
Many applications seek high speed and performance under less
than ideal operating conditions. In these application circuits,
the implementation and construction of the PCB is as
important as the circuit design. Proper RF techniques must be
used for device selection, placement, and routing, as well as for
power supply bypassing and grounding to ensure optimum
performance.
Figure 56. LVPECL Far-End Termination
05286-031
3.3V
LVPECL DIFFERENTIAL
(COUPLED)
3.3V
LVPECL
100Ω
0.1nF
0.1nF
200Ω200Ω
Figure 57. LVPECL with Parallel Transmission Line
AD9511
Rev. A | Page 57 of 60
OUTLINE DIMENSIONS
PIN 1
INDICATOR
TOP
VIEW 6.75
BSC SQ
7.00
BSC SQ
1
48
12
13
37
36
24
25
5.25
5.10 SQ
4.95
0.50
0.40
0.30
0.30
0.23
0.18
0.50 BSC
12° MAX
0.20REF
0.80 MAX
0.65 TYP
1.00
0.85
0.80
5.50
REF
0.05 MAX
0.02 NOM
0.60 MAX
0.60 MAX PIN 1
INDICATOR
COPLANARITY
0.08
SEATING
PLANE
0.25 MIN
EXPOSED
PAD
(BOTTOM VIEW)
COMPLIANT TO JEDEC STANDARDS MO-220-VKKD-2
Figure 59. 48-Lead Lead Frame Chip Scale Package [LFCSP_VQ]
7 mm × 7 mm Body, Very Thin Quad
(CP-48-1)
Dimensions shown in millimeters
ORDERING GUIDE
Model Temperature Range Package Description Package Option
AD9511BCPZ −40°C to +85°C 48-Lead Lead Frame Chip Scale Package (LFCSP_VQ) CP-48-1
1
AD9511BCPZ-REEL7 −40°C to +85°C 48-Lead Lead Frame Chip Scale Package (LFCSP_VQ) CP-48-1
1
AD9511/PCB Evaluation Board without VCO, VCXO, or Loop Filter
AD9511-VCO/PCB Evaluation Board with 245.76 MHz VCXO, Loop Filter
1 Z = Pb-free part.
AD9511
Rev. A | Page 58 of 60
NOTES
AD9511
Rev. A | Page 59 of 60
NOTES
AD9511
Rev. A | Page 60 of 60
NOTES
©2005 Analog Devices, Inc. All rights reserved. Trademarks and
registered trademarks are the property of their respective owners.
D05286–0–6/05(A)
