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dc1795af
DEMO MANUAL DC1795A
Description
LTC6950
1.4GHz Low Phase Noise, Low Jitter PLL
with Clock Distribution
Demonstration circuit 1795A features the LT C
®
6950, a
1.4GHz low phase noise, low jitter PLL with clock dis-
tribution.
For ease of use, the DC1795A comes installed with a
100MHz reference and a 1GHz VCSO, voltage controlled
SAW oscillator with sine wave output. All differential
inputs and outputs have 0.5" spaced SMA connectors.
The DC1795A has four AC coupled LVPECL outputs with
50Ω transmission lines making them suitable to drive
50Ω impedance instruments. The LVDS/CMOS output is
DC coupled. The LTC6950’s EZSync™ function is made
available via a turret and an SMA connector.
L, LT, LTC, LTM, Linear Technology and the Linear logo are registered trademarks and EZSync
and ClockWizard are trademarks of Linear Technology Corporation. All other trademarks are the
property of their respective owners.
For the evaluation of the LTC6950 with other VCOs and
references, the DC1795A can be modified to accommodate
different on-board or external components. It also allows
the user the option of a passive or active loop filter.
A DC590 USB serial controller board is used for SPI com-
munication with the LTC6950, controlled by the supplied
ClockWizard™ software.
Design files for this circuit board are available at
http://www.linear.com/demo/DC1795A
Figure 1. DC1795A Connections
Ribbon
cable
connecon
to DC590
LVDS/CMOS
DC-coupled
Outputs, SMA PECL0
AC Coupled
Outputs, SMA
Frequency Reference
In
p
ut
,
SMA
PECL1
AC Coupled
Outputs, SMA
PECL2
AC Coupled
Outputs, SMA
PECL3
AC Coupled
Outputs, SMA
5V DC Supply,
BNC & turret
3.3V DC Supply,
BNC & turret
5V U4 (VCXO) DC
Supply, turret
U3 (VCO) DC
Supply, turret
External VCO
Input, SMA
External VCO Charge
Pump Output, SMA
and turret
Acve Loop Filter
Op-amp (U2) DC
Su
pp
l
y
, turret
EZSyncTM
SYNC Input,
SMA & turret
Stat Outputs,
turrets
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dc1795af
DEMO MANUAL DC1795A
Quick start proceDure
The DC1795A is easy to set up to evaluate the performance
of the LTC6950. Follow the procedure below.
The DC590 and ClockWizard application are required to
control the DC1795A through a personal computer (PC).
DC590 CONFIGURATION
Place the DC590 jumpers in the following positions (refer
to Figure 2):
JP4: EE - Must be in the EN position.
JP5: ISO - ON must be selected.
JP5: SW - ON must be selected.
JP6: VCCIO - 3.3V or 5V must be selected. This sets
the SPI port to 3.3V or 5V operation. 3.3V operation is
recommended.
Connect the DC590 to one of your computer’s USB ports
with the included USB cable.
CLOCKWIZARD INSTALLATION
The ClockWizard software is used to communicate with
the LTC6950. It uses the DC590 to translate between USB
and SPI-compatible serial communications formats. It also
includes advanced PLL design and simulation capabilities.
The following are the ClockWizard system requirements:
• Windows Operating System: Windows XP, Windows
2003 Server, Windows Vista, Windows 7
• Microsoft .NET 3.5 SP1 or later
• Windows Installer 3.1 or later
• Linear Technology’s DC590 hardware
Figure 2. DC590 Jumper and Connector Locations
JP6
jumpers
J4,ribbon
cable
connection
tothe
DC1795
JP5jumpers
JP4
jumper
J3,USB
connection
toPC
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dc1795af
DEMO MANUAL DC1795A
Quick start proceDure
Download the ClockWizard setup file at www.linear.com/
ClockWizard.
Run the ClockWizard setup file and follow the instructions
given on the screen. The setup file will verify and/or install
Microsoft .NET and install the ClockWizard. Refer to the
Help menu for software operation.
DC1795A CONFIGURATION
1. Connect the GND, V+ = 3.15V to 3.45V, V+ to 5.25V and
V+ VCXO turrets to a power supply and apply power
(see Figure 1 and the Typical DC1795A Requirements
and Characteristics table).
2. Connect the DC590 to the DC1795A with the provided
ribbon cable.
3. Run the ClockWizard application.
4. In ClockWizard, click File > Load Settings and point to
the “LTC6950_PECL0_250MHz.clkset” file.
The green “STAT1” LED on the DC1795A should turn on
and the “STAT2” LED should turn off indicating that the
loop is locked at 1000MHz. A 250MHz signal should be
present on the PECL0 outputs.
Be sure to power down or terminate any unused RF output
with 50Ω, or poor spurious performance may result.
Figure 3. ClockWizard Screenshot
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dc1795af
DEMO MANUAL DC1795A
Quick start proceDure
TROUBLESHOOTING
If the green LED does not illuminate, follow the instruc-
tions below:
1. Verify that you are able to communicate with the
DC1795A. The bottom status line in ClockWizard should
read “LTC6950” and “Comm Enabled.”
2. Verify that V+ = 3.15V to 3.45V, V+ to 5.25V and V+
VCXO turrets have the correct voltages on them (see
the Typical DC1795A Requirements and Characteristics
table).
3. Select “Status” Output = 2 in ClockWizard’s System
Tab. Click “Read All.” See if the NO_VCO or NO_REF
boxes in the second column are checked.
a. If NO_REF is checked, verify the “V+ XO” test point
voltage is set to 3.3V. Verify R73 is installed (0 ohm)
b. IF NO_VCO is checked, verify the components between
U4 and U1 match the default BOM.
Contact the factory for further troubleshooting.
Dc1795a reconfiguration
The DC1795A allows the use of a variety of references,
VCOs and active or passive loop filters. The following
covers the hardware reconfiguration of the DC1795A.
Refer to ClockWizard and the LTC6950 data sheet to bet-
ter understand how to change programmed parameters
on the DC1795A.
LTC6950 CLKSET FILES
The ClockWizard provides three different clkset files for
evaluation purposes. These files were made for the default
bill of materials. If board modifications are made, these
files or the loop filter may need to be modified for the
LTC6950 to lock correctly.
1. LTC6950_PECL0_250MHz.clkset: Produces a 250MHz
output on PECL0. All other outputs are powered down.
2. LTC6950_Figure16_250MHZ.clkset: Matches Figure
16 of the LTC6950 data sheet. To sync outputs, refer
to the EZSync Function section.
3. LTC6950_ALL_CHAN_250MHz.clkset: Produces a
250MHz output on all five outputs. To sync outputs,
refer to the EZSync Function section.
EZSync FUNCTION
Apply a 1ms or longer high pulse to the SYNC SMA con-
nector to take advantage of the EZSync function. Refer
to the LTC6950 data sheet for SYNC timing and level
requirements.
LVPECL OUTPUT OPTIONS
The DC1795A has four AC coupled LVPECL outputs.
Internal biasing (IBIASx = H) is required with this default
termination network. The DC1795A has options for pull
down or series resistors to accommodate the other LVPECL
termination networks described in the data sheet.
LVDS/CMOS OUTPUT OPTIONS
The LVDS/CMOS output is DC coupled without on-board
termination by default. The DC1795A provides pull down,
series and a differential termination resistor options to
accommodate other termination networks described in
the data sheet.
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DEMO MANUAL DC1795A
Dc1795a reconfiguration
REFERENCE OPTIONS
Table 1 details the available reference options and board
modifications for each available option. The CLKSET files
described above assume the noise profile of the default
reference. If a different reference is used, change the
reference noise profile in ClockWizard before simulating
the LTC6950 under the Loop Design tab.
VCO INPUT OPTIONS
Table 2 describes the available VCO input options. Board
modifications and power requirements for each option are
also provided in Table 2. There are two different oscillator
footprints on the board: U3, which accommodates the
popular 0.5" × 0.5" package, and U4, which accommodates
another common 14mm × 9mm package with four or six
pins. U4 also accommodates the smaller 5mm × 7.5mm
package. An external connectorized VCO can also drive the
LTC6950 through SMA connector J15. The CLKSET files
described above assume the noise profile for the default
VCO. If a different VCO is used, change the VCO noise
profile in ClockWizard before simulating the LTC6950
under the Loop Design tab.
CLOCK FOLLOWER
When using the LTC6950 as a clock follower the LTC6950’s
PLL circuitry can be powered down by setting the PDPLL
bit in ClockWizard. This will reduce the LTC6950’s overall
power consumption. Table 2 describes how to reconfigure
the board for a differential external input when using the
LTC6950 as a clock follower. Refer to the EZSync Function
section and to the data sheet for more details on using
the LTC6950 as a clock follower.
LOOP FILTER DESIGN AND INSTALLATION
Tables 3, 4 and 5 cross reference the loop filter options
shown in ClockWizard’s Loop Design tab with the DC1795A
component reference designators. Table 3 is dedicated to
the default oscillator, component U4. Table 4 is dedicated to
another common oscillator footprint, component U3. Table 5
can be used with external oscillators. Use ClockWizard to
select, design and simulate different loop filters.
Some VCO tuning voltage ranges are greater than the
LTC6950 charge pump voltage range (refer to the LTC6950
data sheet). In such cases, an active loop filter using an
op amp can deliver the required tuning voltage. When
satisfied with the loop filter design, use Tables 3, 4 and 5
to help identify which components should be modified.
The loop filter components are located on the bottom side
of the DC1795A.
Table 1. Reference Options and Board Modifications
DEFAULT
OPTION
REFERENCE
OPTION INSTALL DEPOPULATE LTC6950 PERFORMANCE COMMENTS
lOn-Board NA NA Limited by on board reference at
frequency offsets <10kHz
U9 can accommodate any 5mm × 7.5mm or
9mm × 14mm oscillator package
External C67
0402 0.1µF R73, C71 Best performance when using an
ultralow noise external reference
For improved performance connect J4 to a very low
noise reference, such as the Wenzel 501-04517D
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DEMO MANUAL DC1795A
Dc1795a reconfiguration
Table 2. VCO Input Options: Power Settings and Board Modifications
DEFAULT
OPTION
BOARD MODIFICATIONS OSCILLATOR POWER SETTINGS
COMMENTSOSCILLATOR INSTALL DEPOPULATE
V+ OA
TURRET
V+ VXCO
TURRET
V+ VCO
TURRET
EN
TURRET
lU4 NA
(Default)
NA
(Default)
[For Active Filters
Only] Determined by
U4 VTUNE specification.
5V for Default U4.
Must be less than 24V
Determined
by U4 VCC
specification.
5V for Default
U4. Must be
less than 24V
- Connects to
pin 2 of U4.
Not used with
Default U4
Refer to Table 3: loop
filter component
selections for U4
U3 U3, *C38
0402 0Ω
*R43 [For Active Filters
Only] Determined by
U3 VTUNE specification.
Must be less than 24V
- Determined
by U3 VCC
specification.
Must be less
than 24V
- Refer to Table 4: loop
filter component
selections for U3
Single-Ended
External
*C25
0402 0Ω
*R25, R40,
R41
[For Active Filters
Only] Determined by
External Oscillator
VTUNE specification,
must be less than 24V
- - - Connect signal to
J15. Refer to Table 5:
loop filter component
selections.
Differential
External
*C25, C26
0402 0Ω
C69 0402
~100pF
*R25, R40,
R41
[For Active Filters
Only] Determined by
External Oscillator
VTUNE specification,
must be less than 24V
- - - Connect signals to J14
and J15. [For External
Oscillator Only] Refer
to Table 5: loop filter
component selections.
* General Recommendations: There are several termination and common mode options on the DC1795A for different input signal types. Refer to the
DC1795A schematic, the LTC6950 data sheet and the data sheet for the VCO or clock distribution component used for an optimum termination network.
Table 3. Loop Filter Selection for U4 Oscillator (Refer to ClockWizard’s Loop Design Tab)
DEFAULT
OPTION
CLOCKWIZARD AND BOM CROSS REFERENCE OTHER MODIFICATIONS
COMMENTS
LOOP FILTER
TYPE RZ CI CP R1 C2 L1 INSTALL DEPOPULATE
lFilter 1 (Passive) RZ_P CI1_P + CI2_P CP_P - - - - - RZ_P, CI1_P, CI2_P, CP_P
populated with default values
Filter 2 (Passive) RZ_P CI1_P + CI2_P CP_P R12 C22 - - -
Filter 3 (Passive) RZ_P CI1_P + CI2_P CP_P R72 C22 R12 - -
Filter 4 (Active) RZ_A CI1_A + CI2_A CP_A R12 C22 - R69, R71
(0402 0Ω)
R70, R72 Select CPINV under the
ClockWizard System tab
Table 4. Loop Filter Selection for U3 Oscillator (Refer to ClockWizard’s Loop Design Tab)
DEFAULT
OPTION
CLOCKWIZARD AND BOM CROSS REFERENCE OTHER MODIFICATIONS
COMMENTSLOOP FILTER TYPE RZ CI CP R1 C2 L1 INSTALL DEPOPULATE
Filter 1 (Passive) RZ_P CI1_P + CI2_P CP_P - - - R18
(0402 0Ω)
R12
Filter 2 (Passive) RZ_P CI1_P + CI2_P CP_P R18 C29 - R12
Filter 3 (Passive) RZ_P CI1_P + CI2_P CP_P R72 C29 R18 - R12
Filter 4 (Active) RZ_A CI1_A + CI2_A CP_A R18 C29 - R69, R71
(0402 0Ω)
R12, R70,
R72
Select CPINV under the
ClockWizard System tab
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DEMO MANUAL DC1795A
Dc1795a reconfiguration
Table 5. Loop Filter Selection for External Oscillator (Refer to ClockWizard’s Loop Design Tab)
DEFAULT
OPTION
CLOCKWIZARD AND BOM CROSS REFERENCE OTHER MODIFICATIONS
COMMENTSLOOP FILTER TYPE RZ CI CP INSTALL DEPOPULATE
Filter 1 (Passive) RZ_P CI1_P + CI2_P CP_P R68
(0402 0Ω)
R72 Connect CPOUT turret to VTUNE of
external oscillator
Filter 4 (Active) RZ_A CI1_A + CI2_A CP_A R67, R69
(0402 0Ω)
R70, R72 Select CPINV under the ClockWizard
System tab. Connect CPOUT turret to
VTUNE of external oscillator
typical Dc1795a reQuirements anD characteristics
PARAMETER INPUT OR OUTPUT PHYSICAL LOCATION DETAILS
3.3V Power Supply Input J2 BNC connector, or
V+ = 3.15V to 3.45V turret
Low-noise and spur-free 3.3V,
500mA default (200mA configured*).
Powers LTC6950, U6, U7, U8 and U9
Charge Pump Power Supply Input J1 BNC connector, or
V+ to 5.25V turret
Low-noise and spur-free 5V, 35mA*.
Powers LTC6950 and provides common mode to U2
VCXO/VCSO Power Supply Input V+ VCXO turret Low-noise and spur-free 5V, 20mA*. Powers U4
LVDS/CMOS+, LVDS/CMOS–Two Outputs J19 and J18 SMA connectors** DC coupled, 250MHz, (if enabled)*.
Refer to LTC6950 data sheet for output levels for LVDS and
CMOS option.
PECL0+, PECL0–Two Outputs J17 and J16 SMA connectors** AC coupled, 250MHz, 800mVP differential*.
Must have LTC6950’s IBIAS0 = H with default BOM. DC1795A
has options for an external pull down resistor if IBIAS0 = L.
PECL1+, PECL1–Two Outputs J13 and J12 SMA connectors** AC coupled, 250MHz, 800mVP differential (if enabled)*. Must
have LTC6950’s IBIASX = H with default BOM. DC1795A has
options for an external pull down resistor if IBIASX = L.
PECL2+, PECL2–Two Outputs J8 and J7 SMA connectors**
PECL3+, PECL3–Two Outputs J11 and J10 SMA connectors**
SYNC Input SYNC turret or J9 SMA connector EZSync, 0V to 3.3V control signal, refer to the data sheet
STAT1, STAT2 Output STAT1 and STAT2 turret STAT1 GREEN LED, if ON LTC6950 is locked*.
STAT2 RED LED, if ON indicates issue*.
Refer to the troubleshooting section and data sheet
Loop Bandwidth - Set by loop filter component values 4.2kHz*
VCO Power Supply Input V+ VCO turret Board Modifications required for use, see Table 2
Active Loop Filter Supply Input V+ OA turret Board Modifications required for use, see Table 2
REF, External Reference Input J4 SMA connector Board Modifications required for use, see Table 1
VCO+, VCO–, External VCO or
Input for clock distribution
Input J14 and J15 SMA connectors Board Modifications required to use External VCO.
See Tables 2 and 5. Clock Distribution, see Table 2 only
CPOUT Output CPOUT Turret Used with External VCO, connect to external VCO’s VTUNE
voltage
* These values are for the “LTC6950_PECL0_250MHz” file and the default on board VCO and Reference.
** Any unused RF output must be powered down or terminated with 50Ω, or poor spurious performance may result.
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dc1795af
DEMO MANUAL DC1795A
layout top layer
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DEMO MANUAL DC1795A
parts list
ITEM QTY REFERENCE PART DESCRIPTION MANUFACTURER/PART NUMBER
1 0 CI1_A, C22, C29, CP_A CAP., 0603 OPT
2 1 CI1_P CAP., X7R, 0.1µF, 25V, 10%, 0603 AVX, 06033C104KAT2A
3 0 CI2_A CAP., 1206 OPT
4 1 CI2_P CAP., X7R, 0.56µF, 25V, 10%, 1206 AVX, 12063C564KAT2A
5 1 CP_P CAP., X7R, 0.056µF, 16V, 10%, 0603 AVX, 0603YC563KAT2A
6 3 C1, C3, C7 CAP., TANT, 47µF, 20V, 20%, 7343 AVX, TAJD476M020HNJ
7 2 C2, C8 CAP., X7R, 1µF, 10V, 10%, 0603 AVX, 0603ZC105KAT2A
8 20 C4, C9-C19, C42-C48, C60 CAP., X7R, 0.01µF, 6.3V, 10%, 0201 AVX, 02016C103KAT2A
9 3 C5, C24, C32 CAP., X7R, 0.1µF, 50V, 10%, 0805 AVX, 08055C104KAT2A
10 29 C6, C28, C31, C33-C36, C39-C41, C49-C58,
C61-C66, C71, C73, C74
CAP., X7R, 0.1µF, 10V, 10%, 0402 AVX, 0402ZC104KAT2A
11 3 C23, C30, C59 CAP., TANT, 47µF, 35V, 10%, 7361 AVX, TAJV476K035RNJ
12 0 C25-C27, C38, C67, C69, C70 CAP., 0402 OPT
13 2 C68, C72 CAP., NPO, 100pF, 25V, 10%, 0402 AVX, 04023A101KAT2A
14 1 D1 LED, GREEN, LED-ROHM-SML-010FT ROHM, SML-010FTT86L
15 1 D2 LED, RED, LED-ROHM-SML-010VT ROHM, SML-010VTT86L
16 15 E1-E11, E16, E17, E20, E21 TURRET, TESTPOINT 0.064" MILL-MAX, 2308-2-00-80-00-00-07-0
17 2 J1, J2 CONN, BNC, 5 PINS CONNEX, 112404
18 2 J3, J9 CONN., SMA 50Ω STRAIGHT MOUNT CONNEX, 132134
19 13 J4, J7, J8, J10-J19 CONN., SMA 50Ω EDGE-LAUNCH EMERSON, 142-0701-851
20 1 J5 CONN., HEADER, 14 PIN, 2mm MOLEX, 87831-1420
21 1 RZ_P RES., CHIP, 196Ω, 1/16W, 1%, 0603 VISHAY, CRCW0603196RFKEA
22 5 R1, R2, R4, R5, R10 RES., CHIP, 4.99k, 1/16W, 1% 0402 VISHAY, CRCW04024K99FKED
23 0 R6, R9, R17, R19, R21-R24, R26, R30-R33,
R36, R38, R42, R46, R52, R57, R60, R61
RES., 0402 OPT
24 4 R7, R16, R28, R29 RES., CHIP, 49.9, 1/16W, 1% 0402 VISHAY, CRCW040249R9FKED
25 15 R8, R43, R44, R55, R56, R62-R66, R74-R78 RES., CHIP, 0Ω, 0402 VISHAY, CRCW04020000Z0ED
26 5 R11, R12, R70, R72, R73 RES., CHIP, 0Ω, 0603 YAGEO, RC0603JR-070RL
27 5 R13-R15, R35, R58 RES., CHIP, 200K, 1/16W, 1% 0402 VISHAY, CRCW0402200KFKED 2rls
28 0 R18, R67-R69, R71, RZ_A, R53 RES., 0603 OPT
29 5 R20, R51, R54, R59, R79 RES., CHIP, 100, 1/16W, 1% 0402 NIC, NRC04F1000TRF
30 2 R25, R40 RES., CHIP, 150, 1/16W, 1% 0402 VISHAY, CRCW0402150RFKED
31 2 R37, R39 RES., CHIP, 330, 1/16W, 1% 0402 VISHAY, CRCW0402330RFKED
32 1 R41 RES., CHIP, 37.4, 1/16W, 1% 0402 VISHAY, CRCW040237R4FKED
33 1 U1 I.C. LTC6950IUHH, QFN48UHH-5X9 LINEAR TECH., LTC6950IUHH#PBF
34 1 U2 I.C. LT1678IS8, SO8 LINEAR TECH., LT1678IS8#PBF
35 0 U3 VCO, 0.5" × 0.5" OPT
36 1 U4 VCSO, 1GHz 5V CRYSTEK, CVCSO-914-1000.000
37 1 U5 I.C., SERIAL EEPROM, TSSOP8 MICROCHIP, 24LC025-I /ST
38 2 U6, U7 I.C., DUAL BUFFER, SC70-6 FAIRCHILD SEMI., NC7WZ17P6X
39 1 U8 I.C., DUAL TRANSCEIVER, SOT363 NXP, 74LVC 1T45GW
40 1 U9 CLOCK OSCILLATOR, 100MHz, 3.3V CRYSTEK, CCHD-575-25-100.000
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dc1795af
DEMO MANUAL DC1795A
schematic Diagram
A
A
B
B
C
C
D
D
E
E
4 4
3 3
2 2
1 1
NOTE: UNLESS OTHERWISE SPECIFIED
1. ALL RESISTORS ARE IN OHMS, 0402
2. ALL CAPACITORS ARE IN MICROFARADS, 0402
(LOK)
(ERR)
*
*
*
THE LAYOUT FOOTPRINT FOR U4 AND U9 ACCEPTS
MOST OSCILLATORS IN 9mm X 14mm OR 5mm X
7.5mm PACKAGES WITH EITHER FOUR OR SIX PINS.
V+OA
V+VCO
V+
V+OA
V+CP
V+VCXO
V+VCO
V+VCXO
V+CP
V+
SDI
SCLK
SDO
CS
SIZE
DATE:
IC NO. REV.
SHEET OF
TITLE:
APPROVALS
PCB DES.
APP ENG.
TECHNOLOGY Fax: (408)434-0507
Milpitas, CA 95035
Phone: (408)432-1900
1630 McCarthy Blvd.
LTC Confidential-For Customer Use Only
CUSTOMER NOTICE
LINEAR TECHNOLOGY HAS MADE A BEST EFFORT TO DESIGN A
CIRCUIT THAT MEETS CUSTOMER-SUPPLIED SPECIFICATIONS;
HOWEVER, IT REMAINS THE CUSTOMER'S RESPONSIBILITY TO
VERIFY PROPER AND RELIABLE OPERATION IN THE ACTUAL
APPLICATION. COMPONENT SUBSTITUTION AND PRINTED
CIRCUIT BOARD LAYOUT MAY SIGNIFICANTLY AFFECT CIRCUIT
PERFORMANCE OR RELIABILITY. CONTACT LINEAR
TECHNOLOGY APPLICATIONS ENGINEERING FOR ASSISTANCE.
THIS CIRCUIT IS PROPRIETARY TO LINEAR TECHNOLOGY AND
SCHEMATIC
SUPPLIED FOR USE WITH LINEAR TECHNOLOGY PARTS.
SCALE = NONE
www.linear.com
2
03/24/2014, 05:07 PM
12
1.4 GHZ LOW PHASE NOISE, LOW JITTER PLL WITH CLOCK DISTRIBUTION
KIM T.
MICHEL A.
N/A
LTC6950IUHH
DEMO CIRCUIT 1795A
SIZE
DATE:
IC NO. REV.
SHEET OF
TITLE:
APPROVALS
PCB DES.
APP ENG.
TECHNOLOGY Fax: (408)434-0507
Milpitas, CA 95035
Phone: (408)432-1900
1630 McCarthy Blvd.
LTC Confidential-For Customer Use Only
CUSTOMER NOTICE
LINEAR TECHNOLOGY HAS MADE A BEST EFFORT TO DESIGN A
CIRCUIT THAT MEETS CUSTOMER-SUPPLIED SPECIFICATIONS;
HOWEVER, IT REMAINS THE CUSTOMER'S RESPONSIBILITY TO
VERIFY PROPER AND RELIABLE OPERATION IN THE ACTUAL
APPLICATION. COMPONENT SUBSTITUTION AND PRINTED
CIRCUIT BOARD LAYOUT MAY SIGNIFICANTLY AFFECT CIRCUIT
PERFORMANCE OR RELIABILITY. CONTACT LINEAR
TECHNOLOGY APPLICATIONS ENGINEERING FOR ASSISTANCE.
THIS CIRCUIT IS PROPRIETARY TO LINEAR TECHNOLOGY AND
SCHEMATIC
SUPPLIED FOR USE WITH LINEAR TECHNOLOGY PARTS.
SCALE = NONE
www.linear.com
2
03/24/2014, 05:07 PM
12
1.4 GHZ LOW PHASE NOISE, LOW JITTER PLL WITH CLOCK DISTRIBUTION
KIM T.
MICHEL A.
N/A
LTC6950IUHH
DEMO CIRCUIT 1795A
SIZE
DATE:
IC NO. REV.
SHEET OF
TITLE:
APPROVALS
PCB DES.
APP ENG.
TECHNOLOGY Fax: (408)434-0507
Milpitas, CA 95035
Phone: (408)432-1900
1630 McCarthy Blvd.
LTC Confidential-For Customer Use Only
CUSTOMER NOTICE
LINEAR TECHNOLOGY HAS MADE A BEST EFFORT TO DESIGN A
CIRCUIT THAT MEETS CUSTOMER-SUPPLIED SPECIFICATIONS;
HOWEVER, IT REMAINS THE CUSTOMER'S RESPONSIBILITY TO
VERIFY PROPER AND RELIABLE OPERATION IN THE ACTUAL
APPLICATION. COMPONENT SUBSTITUTION AND PRINTED
CIRCUIT BOARD LAYOUT MAY SIGNIFICANTLY AFFECT CIRCUIT
PERFORMANCE OR RELIABILITY. CONTACT LINEAR
TECHNOLOGY APPLICATIONS ENGINEERING FOR ASSISTANCE.
THIS CIRCUIT IS PROPRIETARY TO LINEAR TECHNOLOGY AND
SCHEMATIC
SUPPLIED FOR USE WITH LINEAR TECHNOLOGY PARTS.
SCALE = NONE
www.linear.com
2
03/24/2014, 05:07 PM
12
1.4 GHZ LOW PHASE NOISE, LOW JITTER PLL WITH CLOCK DISTRIBUTION
KIM T.
MICHEL A.
N/A
LTC6950IUHH
DEMO CIRCUIT 1795A
REVISION HISTORY
DESCRIPTION DATEAPPROVEDECO REV
MICHEL A.PRODUCTION2 03-24-14
__
REVISION HISTORY
DESCRIPTION DATEAPPROVEDECO REV
MICHEL A.PRODUCTION2 03-24-14
__
REVISION HISTORY
DESCRIPTION DATEAPPROVEDECO REV
MICHEL A.PRODUCTION2 03-24-14
__
R36
OPT
R36
OPT
C58
0.1uF
C58
0.1uF
R28
49.9
R28
49.9
CI1_A OPT
0603
CI1_A OPT
0603
C27 OPTC27 OPT
R6
OPT
R6
OPT
RZ_P
196
0603
RZ_P
196
0603
R42
OPT
R42
OPT
R71
OPT
0603
R71
OPT
0603
A
B
U2 LT1678IS8
A
B
U2 LT1678IS8
OUTA 1
-INA 2
+INA 3
V- 4
+INB
5
-INB
6
OUTB
7
V+
8
J8 PECL2+
J8 PECL2+
C32 0.1uF
0805
C32 0.1uF
0805
R70
0
0603
R70
0
0603
C50
0.1uF
C50
0.1uF
J14
VCO+ J14
VCO+
CP_A OPT
0603
CP_A OPT
0603
R73 0
0603
R73 0
0603
C52
0.1uF
C52
0.1uF
R22
OPT
R22
OPT
C25 OPTC25 OPT
J13 PECL1+
J13 PECL1+
C40
0.1uF
C40
0.1uF
C70
OPT
C70
OPT
C66
0.1uF
C66
0.1uF
R32
OPT
R32
OPT
+
C23
35V
47uF
7361
+
C23
35V
47uF
7361
C29
OPT
0603
C29
OPT
0603
E10
STAT1 E10
STAT1
J9
SYNC J9
SYNC
U3
OPT
U3
OPT
GND 1
VTUNE 2
GND 3
GND 4
GND 5
GND 6
GND 7
GND 8
GND
9
RFOUT
10
GND
11
GND
12
GND
13
VCC
14
GND
15
GND
16
C54
0.1uF
C54
0.1uF
J7 PECL2-
J7 PECL2-
R68 OPT
0603
R68 OPT
0603
CI2_P 0.56uF
1206
CI2_P 0.56uF
1206
R29
49.9
R29
49.9
R1 4.99KR1 4.99K
J18 LVDS/CMOS-
J18 LVDS/CMOS-
R67 OPT
0603
R67 OPT
0603
+
C30
35V
47uF
7361
+
C30
35V
47uF
7361
R53
OPT
R53
OPT
J19 LVDS/CMOS+
J19 LVDS/CMOS+
R52
OPT
R52
OPT
RZ_A OPT
0603
RZ_A OPT
0603
J12 PECL1-
J12 PECL1-
C57
0.1uF
C57
0.1uF
C56
0.1uF
C56
0.1uF
J11 PECL3+
J11 PECL3+
R39
330
R39
330
CI1_P 0.1uF
0603
CI1_P 0.1uF
0603
E11
STAT2 E11
STAT2
R61
OPT
R61
OPT
R55
0
R55
0
E2
V+OA E2
V+OA
J15
VCO- J15
VCO-
C49
0.1uF
C49
0.1uF
U4
CVCSO-914-1000
U4
CVCSO-914-1000
VTUNE
1
EN
2
GND
3OUT+ 4
OUT- 5
VCC 6
J17 PECL0+
J17 PECL0+
+
C3
20V
47uF
7343
+
C3
20V
47uF
7343
R35
200K
R35
200K
R2
4.99K
R2
4.99K
R65
0
R65
0
C24 0.1uF
0805
C24 0.1uF
0805
J3
CPOUT J3
CPOUT
C22
OPT 0603
C22
OPT 0603
R18
OPT
0603
R18
OPT
0603
R72
0
0603
R72
0
0603
J4 REF
J4 REF
C71
0.1uF
C71
0.1uF
J16 PECL0-
J16 PECL0-
R31
OPT
R31
OPT R66
0
R66
0
R17
OPT
R17
OPT
R69
OPT
0603
R69
OPT
0603
R12 0
0603
R12 0
0603
R30
OPT
R30
OPT
E7
GND E7
GND
J10 PECL3-
J10 PECL3-
R74
0
R74
0
R46
OPT
R46
OPT
C51
0.1uF
C51
0.1uF
C69
OPT
C69
OPT
E4
CPOUT E4
CPOUT
R21
OPT
R21
OPT
E9
SYNC E9
SYNC
C67
OPT
C67
OPT
R9 OPTR9 OPT
C72
100pF
C72
100pF
R75
0
R75
0
CPCP
R16
49.9
R16
49.9
V+XOV+XO
E17
GND E17
GND
R40
150
R40
150
R43 0R43 0
D1
SML-010MT
GRN
D1
SML-010MT
GRN
12
E16
V+VCO E16
V+VCO
C53
0.1uF
C53
0.1uF
U9
CCHD-575-25-100
U9
CCHD-575-25-100
VTUNE 1
EN 2
GND 3
OUT+
4
OUT-
5
VCC
6
R76
0
R76
0
R26
OPT
R26
OPT
C28
0.1uF
C28
0.1uF
E6
GND E6
GND
R77
0
R77
0
E5
V+VCXO E5
V+VCXO
C55
0.1uF
C55
0.1uF
R60
OPT
R60
OPT
R33 OPTR33 OPT
R20 100R20 100
CI2_A OPT
1206
CI2_A OPT
1206 R23 OPTR23 OPT
C6 0.1uFC6 0.1uF
C38 OPTC38 OPT
U1
LTC6950IUHH
U1
LTC6950IUHH
CP
40
V+CP
39
GND
38
V+
37
V+VCO
36
VCO-
35
VCO+
34
V+VCO
33
V+
32
GND
31
V+ 18
V+P3 1
PECL3- 2
PECL3+ 3
V+P3 4
V+P2 5
PECL2- 6
PECL2+ 7
V+P2 8
V+P1 9
PECL1- 10
PECL1+ 11
V+P1 12
V+P0 13
PECL0- 14
PECL0+ 15
V+P0 16
V+
47
V+REF
46
GND 17
SDO 24
LV/CM- 21
CS 23
V+ 20
V+
25
SCLK
26
SDI
27
STAT1
29
SYNC
30
STAT2
28
LV/CM+ 22
REF+
45
REF-
44
V+
42
V+REF
43
V+ 19
GND
41
GND
48
GND
49
R37
330
R37
330
R78
0
R78
0
R56
0
R56
0
E8
EN E8
EN
R57
OPT
R57
OPT
R8
0
R8
0
C26 OPTC26 OPT
CP_P
0.056uF
0603
CP_P
0.056uF
0603
R62
0
R62
0
R25
150
R25
150 C68
100pF
C68
100pF
R44 0R44 0
+
C59
35V
47uF
7361
+
C59
35V
47uF
7361
R63
0
R63
0
R41 37.4R41 37.4
EN-XOEN-XO
C5 0.1uF
0805
C5 0.1uF
0805
R19
OPT
R19
OPT
D2
SML-010VT
RED
D2
SML-010VT
RED
12
R64
0
R64
0
R38
OPT
R38
OPT
R24
OPT
R24
OPT
R7
49.9
R7
49.9
11
dc1795af
DEMO MANUAL DC1795A
Information furnished by Linear Technology Corporation is believed to be accurate and reliable.
However, no responsibility is assumed for its use. Linear Technology Corporation makes no representa-
tion that the interconnection of its circuits as described herein will not infringe on existing patent rights.
Note: The buffers shown on sheet 2 of 2 of the schematic are used to protect the LTC6950 when connected to the DC590 before the
LTC6950 is powered up. There is no need for such circuitry if the SPI bus is not active before powering up the LTC6950. The EEPROM
is for identification and is not needed to program the LTC6950.
schematic Diagram
A
A
B
B
C
C
D
D
E
E
4 4
3 3
2 2
1 1
NOTE: EEPROM FOR BOARD IDENTIFICATION
DC590 SPI INTERFACE
LTC6950 BYPASS AND BULK CAPACITORS
V+
V+
V+
V+
V+
V+CP
V+
V+
CS
SCLK
SDI
SDO
SIZE
DATE:
IC NO. REV.
SHEET OF
TITLE:
APPROVALS
PCB DES.
APP ENG.
TECHNOLOGY Fax: (408)434-0507
Milpitas, CA 95035
Phone: (408)432-1900
1630 McCarthy Blvd.
LTC Confidential-For Customer Use Only
CUSTOMER NOTICE
LINEAR TECHNOLOGY HAS MADE A BEST EFFORT TO DESIGN A
CIRCUIT THAT MEETS CUSTOMER-SUPPLIED SPECIFICATIONS;
HOWEVER, IT REMAINS THE CUSTOMER'S RESPONSIBILITY TO
VERIFY PROPER AND RELIABLE OPERATION IN THE ACTUAL
APPLICATION. COMPONENT SUBSTITUTION AND PRINTED
CIRCUIT BOARD LAYOUT MAY SIGNIFICANTLY AFFECT CIRCUIT
PERFORMANCE OR RELIABILITY. CONTACT LINEAR
TECHNOLOGY APPLICATIONS ENGINEERING FOR ASSISTANCE.
THIS CIRCUIT IS PROPRIETARY TO LINEAR TECHNOLOGY AND
SCHEMATIC
SUPPLIED FOR USE WITH LINEAR TECHNOLOGY PARTS.
SCALE = NONE
www.linear.com
2
03/24/2014, 05:07 PM
22
1.4 GHZ LOW PHASE NOISE, LOW JITTER PLL WITH CLOCK DISTRIBUTION
KIM T.
MICHEL A.
N/A
LTC6950IUHH
DEMO CIRCUIT 1795A
SIZE
DATE:
IC NO. REV.
SHEET OF
TITLE:
APPROVALS
PCB DES.
APP ENG.
TECHNOLOGY Fax: (408)434-0507
Milpitas, CA 95035
Phone: (408)432-1900
1630 McCarthy Blvd.
LTC Confidential-For Customer Use Only
CUSTOMER NOTICE
LINEAR TECHNOLOGY HAS MADE A BEST EFFORT TO DESIGN A
CIRCUIT THAT MEETS CUSTOMER-SUPPLIED SPECIFICATIONS;
HOWEVER, IT REMAINS THE CUSTOMER'S RESPONSIBILITY TO
VERIFY PROPER AND RELIABLE OPERATION IN THE ACTUAL
APPLICATION. COMPONENT SUBSTITUTION AND PRINTED
CIRCUIT BOARD LAYOUT MAY SIGNIFICANTLY AFFECT CIRCUIT
PERFORMANCE OR RELIABILITY. CONTACT LINEAR
TECHNOLOGY APPLICATIONS ENGINEERING FOR ASSISTANCE.
THIS CIRCUIT IS PROPRIETARY TO LINEAR TECHNOLOGY AND
SCHEMATIC
SUPPLIED FOR USE WITH LINEAR TECHNOLOGY PARTS.
SCALE = NONE
www.linear.com
2
03/24/2014, 05:07 PM
22
1.4 GHZ LOW PHASE NOISE, LOW JITTER PLL WITH CLOCK DISTRIBUTION
KIM T.
MICHEL A.
N/A
LTC6950IUHH
DEMO CIRCUIT 1795A
SIZE
DATE:
IC NO. REV.
SHEET OF
TITLE:
APPROVALS
PCB DES.
APP ENG.
TECHNOLOGY Fax: (408)434-0507
Milpitas, CA 95035
Phone: (408)432-1900
1630 McCarthy Blvd.
LTC Confidential-For Customer Use Only
CUSTOMER NOTICE
LINEAR TECHNOLOGY HAS MADE A BEST EFFORT TO DESIGN A
CIRCUIT THAT MEETS CUSTOMER-SUPPLIED SPECIFICATIONS;
HOWEVER, IT REMAINS THE CUSTOMER'S RESPONSIBILITY TO
VERIFY PROPER AND RELIABLE OPERATION IN THE ACTUAL
APPLICATION. COMPONENT SUBSTITUTION AND PRINTED
CIRCUIT BOARD LAYOUT MAY SIGNIFICANTLY AFFECT CIRCUIT
PERFORMANCE OR RELIABILITY. CONTACT LINEAR
TECHNOLOGY APPLICATIONS ENGINEERING FOR ASSISTANCE.
THIS CIRCUIT IS PROPRIETARY TO LINEAR TECHNOLOGY AND
SCHEMATIC
SUPPLIED FOR USE WITH LINEAR TECHNOLOGY PARTS.
SCALE = NONE
www.linear.com
2
03/24/2014, 05:07 PM
22
1.4 GHZ LOW PHASE NOISE, LOW JITTER PLL WITH CLOCK DISTRIBUTION
KIM T.
MICHEL A.
N/A
LTC6950IUHH
DEMO CIRCUIT 1795A
C39
0.1uF
C39
0.1uF
C2
1.0uF
0603
C2
1.0uF
0603 C44
0.01uF
0201
C44
0.01uF
0201
C62
0.1uF
C62
0.1uF
WPWP
C4
0.01uF
0201
C4
0.01uF
0201
C13
0.01uF
0201
C13
0.01uF
0201
E20
GND E20
GND
SCLKSCLK
R5
4.99K
R5
4.99K
J2
BNC
J2
BNC
GND VCC
U7
NC7WZ17P6X
GND VCC
U7
NC7WZ17P6X
1 6
43
52
R10
4.99K
R10
4.99K
C65
0.1uF
C65
0.1uF
C47
0.01uF
0201
C47
0.01uF
0201
C16
0.01uF
0201
C16
0.01uF
0201
C15
0.01uF
0201
C15
0.01uF
0201
E3
V+ = 3.15V - 3.45V E3
V+ = 3.15V - 3.45V
C74
0.1uF
C74
0.1uF
C36 0.1uF
C36 0.1uF
C63
0.1uF
C63
0.1uF
R13
200K
R13
200K
C12
0.01uF
0201
C12
0.01uF
0201
R58
200K
R58
200K
R79
100
R79
100
GND VCC
U6
NC7WZ17P6X
GND VCC
U6
NC7WZ17P6X
1 6
43
52
C73
0.1uF
C73
0.1uF
C9
0.01uF
0201
C9
0.01uF
0201
R11
0
0603
R11
0
0603
C46
0.01uF
0201
C46
0.01uF
0201
C64
0.1uF
C64
0.1uF
EEGNDEEGND
EEPROM
ARRAY
U5
24LC025-I /ST
EEPROM
ARRAY
U5
24LC025-I /ST
SDA
5
VCC 8
A0
1A1
2A2
3
GND
4
WP
7
SCL
6
+
C7
20V
47uF7343
+
C7
20V
47uF7343
SDISDI
J1
BNC
V+ TO 5.25V
J1
BNC
V+ TO 5.25V
J5
HD2X7-079-MOLEX
J5
HD2X7-079-MOLEX
MOSI/SDA 7
EESDA 9
V+ 1
5V 2
CS 6
SCK/SCL 4
EEVCC 10
MISO 5
EESCL 11
EEGND 12
AUX 14
GND
3
GND
13
GND
8
R15
200K
R15
200K
C11
0.01uF
0201
C11
0.01uF
0201
C43
0.01uF
0201
C43
0.01uF
0201
C8
1.0uF
0603
C8
1.0uF
0603
GND
DIR
VCC(A) VCC(B)
U8
74LVC1T45GW
GND
DIR
VCC(A) VCC(B)
U8
74LVC1T45GW
1 6
43
52
C42
0.01uF
0201
C42
0.01uF
0201
C34 0.1uFC34 0.1uF
R54 100
R54 100
C31
0.1uF
C31
0.1uF
C61
0.1uF
C61
0.1uF
C60
0.01uF
0201
C60
0.01uF
0201
C45
0.01uF
0201
C45
0.01uF
0201
CSCS
C33
0.1uF
C33
0.1uF
C41
0.1uF
C41
0.1uF
C48
0.01uF
0201
C48
0.01uF
0201
C10
0.01uF
0201
C10
0.01uF
0201
C17
0.01uF
0201
C17
0.01uF
0201
R4
4.99K
R4
4.99K
E1E1
SDOSDO
R14
200K
R14
200K
E21
GND E21
GND
R51 100R51 100
C14
0.01uF
0201
C14
0.01uF
0201
C19
0.01uF
0201
C19
0.01uF
0201
R59 100R59 100
C18
0.01uF
0201
C18
0.01uF
0201
+
C120V
47uF7343
+
C120V
47uF7343
C35 0.1uF
C35 0.1uF
V+DIGV+DIG
12
dc1795af
DEMO MANUAL DC1795A
Linear Technology Corporation
1630 McCarthy Blvd., Milpitas, CA 95035-7417
(408) 432-1900 ● FAX: (408) 434-0507 ● www.linear.com
LINEAR TECHNOLOGY CORPORATION 2014
LT 0714 • PRINTED IN USA
DEMONSTRATION BOARD IMPORTANT NOTICE
Linear Technology Corporation (LT C ) provides the enclosed product(s) under the following AS IS conditions:
This demonstration board (DEMO BOARD) kit being sold or provided by Linear Technology is intended for use for ENGINEERING DEVELOPMENT
OR EVALUATION PURPOSES ONLY and is not provided by LT C for commercial use. As such, the DEMO BOARD herein may not be complete
in terms of required design-, marketing-, and/or manufacturing-related protective considerations, including but not limited to product safety
measures typically found in finished commercial goods. As a prototype, this product does not fall within the scope of the European Union
directive on electromagnetic compatibility and therefore may or may not meet the technical requirements of the directive, or other regulations.
If this evaluation kit does not meet the specifications recited in the DEMO BOARD manual the kit may be returned within 30 days from the date
of delivery for a full refund. THE FOREGOING WARRANTY IS THE EXCLUSIVE WARRANTY MADE BY THE SELLER TO BUYER AND IS IN LIEU
OF ALL OTHER WARRANTIES, EXPRESSED, IMPLIED, OR STATUTORY, INCLUDING ANY WARRANTY OF MERCHANTABILITY OR FITNESS
FOR ANY PARTICULAR PURPOSE. EXCEPT TO THE EXTENT OF THIS INDEMNITY, NEITHER PARTY SHALL BE LIABLE TO THE OTHER FOR
ANY INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES.
The user assumes all responsibility and liability for proper and safe handling of the goods. Further, the user releases LT C from all claims
arising from the handling or use of the goods. Due to the open construction of the product, it is the user’s responsibility to take any and all
appropriate precautions with regard to electrostatic discharge. Also be aware that the products herein may not be regulatory compliant or
agency certified (FCC, UL, CE, etc.).
No License is granted under any patent right or other intellectual property whatsoever. LT C assumes no liability for applications assistance,
customer product design, software performance, or infringement of patents or any other intellectual property rights of any kind.
LT C currently services a variety of customers for products around the world, and therefore this transaction is not exclusive.
Please read the DEMO BOARD manual prior to handling the product. Persons handling this product must have electronics training and
observe good laboratory practice standards. Common sense is encouraged.
This notice contains important safety information about temperatures and voltages. For further safety concerns, please contact a LT C applica-
tion engineer.
Mailing Address:
Linear Technology
1630 McCarthy Blvd.
Milpitas, CA 95035
Copyright © 2004, Linear Technology Corporation
