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Features
• 80 MSPS Maximum Sampling Rate
• Ultra Low Power Dissipation
59 mW/Channel at 80MSPS
• 70.1 dB SNR at 8 MHz FIN
• 0.5 µs Startup from Sleep
15 µs from Power Down
• Reduced Power Dissipation Modes Available
• Internal Reference Circuitry
with No External Components Required
• Coarse and Fine Gain Control
• Internal Offset Correction
• 1.8V Supply Voltage
• Serial 12-Bit LVDS Output
• 14-bit LVDS Output Available Up to 65MSPS
• 64 Lead 9 x 9 mm SMT Package
Typical Applications
• Medical Imaging
• Wireless Infrastructure
• Test and Measurement
• Instrumentation
Pin Compatible Parts
• HMCAD1101
• HMCAD1100
• HMCAD1100/01-AC specications are
also valid for HMCAD1102
Functional Diagram
Figure 1. Functional Block Diagram
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General Description
HMCAD1102 is a high performance low power octal analog-to-digital converter (ADC). The ADC is based on a
proprietary structure and employs internal reference circuitry, a serial control interface and serial LVDS output data.
Data and frame synchronization output clocks are supplied for data capture at the receiver.
Various modes and conguration settings can be applied to the ADC through the serial control interface (SPI). Each
channel can be powered down independently and data format can be selected through this interface. A full chip idle
mode can be set by a single external pin. Register settings determine the exact function of this external pin.
The HMCAD1102 is designed to easily interface with eld-programmable gate arrays (FPGAs) from several vendors.
The very low start up times for the HMCAD1102 allows signicant power reduction in duty-cycled systems, by utilizing
the Sleep Modes or Power Down Mode when the receive path is idle.
Electrical Specications
DC Electrical Specications
AVDD = 1.8V, DVDD = 1.8V, OVDD = 1.8V, 80 MSPS clock, 50% clock duty cycle, -1 dBFS 8 MHz input signal, 12 bit output, unless otherwise noted
Parameter Description Min Typ Max Unit
DC accuracy
No Missing Codes Guaranteed
Offset Error Offset error after internal digital offset correc-
tion 1 LSB
Gain Error ±6 %FS
Gain Matching Gain matching between channels. ±3sigma
value at worst case conditions ±0.5 %FS
DNL Differential nonlinearity (12-bit level) ±0.2 LSB
INL Integral nonlinearity (12-bit level) ±0.6 LSB
VCM Common mode voltage output VAVDD/2
Analog Input
Input Common Mode Analog input common mode voltage VCM -0.1 VCM +0.2 V
Full Scale Range Differential input voltage range 2 Vpp
Input Capacitance Differential input capacitance 2 pF
Bandwidth Input Bandwidth 500 MHz
Power Supply
Analog Supply Voltage 1.7 1.8 2 V
Digital Supply Voltage Digital and output driver supply voltage (up to
65 MSPS) 1.7 1.8 2 V
Digital Supply Voltage Digital and output driver supply voltage (above
65 MSPS) 1.8 1.9 2 V
OVDD Supply Voltage Digital CMOS Input Supply Voltage 1.7 1.8 3.6 V
Temperature
Operating Temperature Operating free-air temperature -40 85 °C
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AC Electrical Specications - 80 MSPS
AVDD = 1.8V, DVDD = 1.8V, OVDD = 1.8V, 80 MSPS clock, 50% clock duty cycle, -1 dBFS 8 MHz input signal, 12 bit output, unless otherwise noted
Parameter Description Min Typ Max Unit
Performance
SNR Signal to Noise Ratio
FIN = 8 MHz 68.5 70.1 dBFS
FIN = 30 MHz 70 dBFS
SINAD Signal to Noise and Distortion Ratio
FIN = 8 MHz 68 69.6 dBFS
FIN = 30 MHz 69.5 dBFS
SFDR Spurious Free Dynamic Range
FIN = 8 MHz 74 77 dBc
FIN = 30 MHz 76 dBc
HD2 Second order Harmonic Distortion
FIN = 8 MHz 85 90 dBc
FIN = 30 MHz 90 dBc
HD3 Third order Harmonic Distortion
FIN = 8 MHz 75 77 dBc
FIN = 30 MHz 76 dBc
ENOB Effective number of Bits
FIN = 8 MHz 11.3 bits
FIN = 30 MHz 11.3 bits
Crosstalk
Signal applied to 7 channels (FIN0). Measure-
ment taken on one channel with full scale at FIN1
.
FIN1=8MHz, FIN0=9.9MHz
95 dBc
Power Supply
Analog Supply Current 173 mA
Digital Supply Current Digital and output driver supply 88 mA
Analog Power 312 mW
Digital Power 158 mW
Total Power Dissipation 470 mW
Power Down Power down mode dissipation 10 µW
Sleep Mode Deep sleep mode power dissipation 56 mW
Sleep Channel Mode Power dissipation with all channels in sleep channel
mode (Light sleep) 116 mW
Sleep Channel Savings Power dissipation savings per channel off 44 mW
Clock Inputs
Max. Conversion Rate 80 MSPS
Min. Conversion Rate 20 MSPS
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Digital and Switching Specications
AVDD = 1.8V, DVDD = 1.8V, OVDD = 1.8V, unless otherwise noted
Parameter Description Min Typ Max Unit
Clock Inputs
Duty Cycle 20 80 % high
Compliance CMOS, LVDS, LVPECL
Input range, diff Differential input swing ±200 mVpp
Input range, sine Differential input swing, sine wave clock input ±800 mVpp
Input range, CMOS Voltage input range CMOS (CLKN connected
to ground) VOVDD
Input common mode voltage Keep voltages within ground and voltage of
OVDD 0.3 VOVDD -0.3 V
Input capacitance Differential 2 pF
Logic inputs (CMOS)
VHI High Level Input Voltage. VOVDD ≥ 3.0V 2 V
VHI High Level Input Voltage. VOVDD = 1.7V – 3.0V 0.8 ·VOVDD V
VLI Low Level Input Voltage. VOVDD ≥ 3.0V 0 0.8 V
VLI Low Level Input Voltage. VOVDD = 1.7V – 3.0V 0 0.2·VOVDD V
IHI High Level Input leakage Current ±10 µA
ILI Low Level Input leakage Current ±10 µA
CIInput Capacitance 3 pF
Data outputs (LVDS)
Compliance LVDS
VOUT Differential output voltage 350 mV
VCM Output common mode voltage 1.2 V
Output coding Default/optional Offset Binary/ 2’s complement
Timing Characteristics
Aperture delay 0.8 ns
Aperture jitter <0.5 ps
TSU
Start up time from Power Down Mode
and Deep Sleep Mode to Active Mode.
References have reached 99% of nal value.
See section “Clock Frequency”
260 992 clock cycles
Start up time from Power Down Mode and
Deep Sleep Mode to Active Mode in µs. 15 µs
TSLPCH
Start up time from Sleep Channel Mode to
Active Mode 0.5 µs
TOVR Out of range recovery time 1 clock cycles
TLAT Pipeline delay 14 clock cycles
LVDS Output Timing Characteristics
tdata
LCLK to data delay time (excluding
programmable phase shift) 250 ps
TPROP Clock propagation delay. 7*TLVDS + 2.6 7*TLVDS + 3.5 7*TLVDS + 4.2 ns
LVDS bit-clock duty-cycle 45 55 %LCLK cycle
Frame clock cycle-to-cycle jitter 2.5 %LCLK cycle
TEDGE Data rise- and fall time 20% to 80% 0.4 ns
TCLKEDGE Clock rise- and fall time 20% to 80% 0.4 ns
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Absolute Maximum Ratings
Applying voltages to the pins beyond those specied
in Table 1 could cause permanent damage to the
circuit.
Table 1: Absolute Maximum Ratings
Pin Reference pin Rating
AVDD AVSS -0.3V to +2.3V
DVDD DVSS -0.3V to +2.3V
OVDD AVSS -0.3V to +3.9V
AVSS / DVSS DVSS / AVSS -0.3V to +0.3V
Analog inputs and
outputs AVSS -0.3V to +2.3V
CLKx AVSS -0.3V to +3.9V
LVDS outputs DVSS -0.3V to +2.3V
Digital inputs DVSS -0.3V to +3.9V
Table 2: Maximum Temperature Ratings
Operating Temperature -40 to +85 °C
Storage Temperature -60 to +150 °C
Maximum Junction Temperature 110 °C
Thermal Resistance (Rth) 25 °C/W
Soldering Prole Qualication J-STD-020
ESD Sensivity HBM Class 1C
ESD Sensivity CDM Class III
ELECTROSTATIC SENSITIVE DEVICE
OBSERVE HANDLING PRECAUTIONS
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 section of this specication is not implied.
Exposure to absolute maximum rating conditions for
extended periods may affect device reliability.
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Pin Conguration and Description
Figure 2. Package diagram
Table 3: Pin Descriptions
Pin Number Function Description
49, 50, 57 AVDD Analog power supply, 1.8V
60 OVDD Digital CMOS Inputs supply voltage
3, 6, 9, 37, 40, 43, 46 AVSS Analog ground
1 IP1 Positive differential input signal, channel 1
2 IN1 Negative differential input signal, channel 1
4 IP2 Positive differential input signal, channel 2
5 IN2 Negative differential input signal, channel 2
7 IP3 Positive differential input signal, channel 3
8 IN3 Negative differential input signal, channel 3
10 IP4 Positive differential input signal, channel 4
11 IN4 Negative differential input signal, channel 4
38 IP5 Positive differential input signal, channel 5
39 IN5 Negative differential input signal, channel 5
41 IP6 Positive differential input signal, channel 6
42 IN6 Negative differential input signal, channel 6
44 IP7 Positive differential input signal, channel 7
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Table 3: Pin Descriptions
Pin Number Function Description
45 IN7 Negative differential input signal, channel 7
47 IP8 Positive differential input signal, channel 8
48 IN8 Negative differential input signal, channel 8
0, 12, 14, 36 DVSS Digital ground
35 DVDD Digital and I/O power supply, 1.8V
13 PD Power-down input. Activate after applying power in order to initialize the ADC
correctly. Alternatively use the SPI power down feature
15 D1P LVDS channel 1, positive output
16 D1N LVDS channel 1, negative output
17 D2P LVDS channel 2, positive output
18 D2N LVDS channel 2, negative output
19 D3P LVDS channel 3, positive output
20 D3N LVDS channel 3, negative output
21 D4P LVDS channel 4, positive output
22 D4N LVDS channel 4, negative output
27 D5P LVDS channel 5, positive output
28 D5N LVDS channel 5, negative output
29 D6P LVDS channel 6, positive output
30 D6N LVDS channel 6, negative output
31 D7P LVDS channel 7, positive output
32 D7N LVDS channel 7, negative output
33 D8P LVDS channel 8, positive output
34 D8N LVDS channel 8, negative output
23 FCLKP LVDS frame clock (1X), positive output
24 FCLKN LVDS frame clock (1X), negative output
25 LCKP LVDS bit clock, positive output
26 LCKN LVDS bit clock, negative output
51 NC Not connected
52 TP Test pin, leave unconnected or connect to ground
53 VCM Common mode output pin, 0.5*AVDD
54 NC Not connected
55 NC Not connected
56 NC Not connected
58 CLKP Positive differential input clock
59 CLKN Negative differential input clock.
61 CSN Chip select enable. Active low
62 SDATA Serial data input
63 SCLK Serial clock input
64 RESETN Reset SPI interface. Active low
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Serial Interface
The HMCAD1102 conguration registers can be accessed through a serial interface formed by the pins SDATA (serial
interface data), SCLK (serial interface clock) and CSN (chip select, active low). The following occurs when CSN is set
low:
• Serial data are shifted into the chip
• At every rising edge of SCLK, the value present at SDATA is latched
• SDATA is loaded into the register every 24th rising edge of SCLK
Multiples of 24-bit words data can be loaded within a single active CSN pulse. If more than 24 bits are loaded into
SDATA during one active CSN pulse, only the rst 24 bits are kept. The excess bits are ignored. Every 24-bit word is
divided into two parts:
• The rst eight bits form the register address
• The remaining 16 bits form the register data
Acceptable SCLK frequencies are from 20 MHz down to a few hertz. Duty-cycle does not have to be tightly controlled.
Timing Diagram
Figure 4 shows the timing of the serial port interface. Table 5 explains the timing variables used in gure 4.
CSN
SCLK
SDATA
t
s
t
h
t
cs
t
chi
t
hi
t
lo
t
ck
t
ch
A7 A6 A5 A4 A3 A2 A1 A0 D15 D14 D13 D12 D11 D10 D9 D8 D7 D6 D5 D4 D3 D2 D1 D0
Figure 3. Serial Port Interface timing
Table 5: Serial Port Interface timing denitions
Parameter Description Minimum Value Unit
tcs Setup time between CSN and SCLK 8 ns
tch Hold time between CSN and SCLK 8 ns
thi SCLK high time 20 ns
tlo SCLK low time 20 ns
tck SCLK period 50 ns
tsData setup time 5 ns
thData hold time 5 ns
Start up Initialization
As part of the HMCAD1102 power-on sequence both a reset and a power down cycle have to be applied to ensure
correct start-up initialization. Make sure that the supply voltages are properly settled before the start up initialization
is being performed. Reset can be done in one of two ways:
1. By applying a low-going pulse (minimum 20 ns) on the RESETN pin (asynchronous).
2. By using the serial interface to set the ‘rst’ bit high. Internal registers are reset to default values when this
bit is set. The ‘rst’ bit is self-reset to zero. When using this method, do not apply any low-going pulse on the
RESETN pin.
Power down cycling can be done in one of two ways:
1. By applying a high-going pulse (minimum 20 ns) on the PD pin (asynchronous).
2. By cycling the SPI register 0Fhex ‘pd’ bit to high (reg value ‘0200’hex) and then low (reg value ‘0000’hex).
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Timing Diagrams
TLVDS
D0 D1 D2 D3 D4 D5 D6 D7 D8 D9 D10 D11 D0 D1 D2 D3 D4 D5 D6 D7 D8 D9 D10
N N N N N N N N N N NN-1 N-1 N-1 N-1 N-1 N-1 N-1 N-1 N-1 N-1 N-1 N-1
N+14
N+15
Analog input
ADC clock
LCLKP
LCLKN
FCLKN
FCLKP
Dxx<1:0> N-2 N-2
D10 D11
TPROP
Figure 4. LVDS timing 12 bit output, DDR mode
D0 D1 D2 D3 D4 D5 D6 D7 D8 D9 D10 D11 D12 D13 D0 D1 D2 D3 D4 D5 D6 D7 D8 D9 D10 D11 D12 D13
N N N N N N N N N N N N N NN-1 N-1 N-1 N-1 N-1 N-1 N-1 N-1 N-1 N-1 N-1 N-1 N-1 N-1
N+14
N+15
Analog input
ADC clock
LCLKN
LCLKP
FCLKN
FCLKP
Dxx<1:0>
TPROP
TLVDS
Figure 5. LVDS timing 14 bit output, DDR mode
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TLVDS
D0 D1 D2 D3 D4 D5 D6 D7 D8 D9 D10 D11 D0 D1 D2 D3 D4 D5 D6 D7 D8 D9 D10
N N N N N N N N N N NN-1 N-1 N-1 N-1 N-1 N-1 N-1 N-1 N-1 N-1 N-1 N-1
N+14
N+15
Analog input
ADC clock
LCLKN
LCLKP
FCLKN
FCLKP
Dxx<1:0> N-2 N-2
D10 D11
TPROP
Figure 6. LVDS timing 12 bit output, SDR mode
TLVDS
TLVDS /2
Dxx<1:0>
tdata
LCLKP
LCLKN
Figure 7. LVDS data timing, DDR mode
Serial Register Map
Table 6: Summary of functions supported by the serial interface
Name Description Default D15 D14 D13 D12 D11 D10 D9 D8 D7 D6 D5 D4 D3 D2 D1 D0 Address
In Hex
rst Self-clearing software
reset Inactive X 00
pd_ch
<8:1>
Channel-specic power-
down Inactive X X X X X X X X
0F
sleep Go to sleep-mode Inactive X
pd Go to power-down Inactive X
pd_pin_cfg
<1:0>
Congures the PD pin for
sleep-modes
PD pin congured for
power-down mode X X
ilvds_lclk
<2:0>
LVDS current drive
programmability for
LCLKP and LCLKN pins
3.5 mA drive X X X
11
ilvds_
frame<2:0>
LVDS current drive
programmability for
FCLKP and FCLKN pins
3.5 mA drive X X X
ilvds_dat
<2:0>
LVDS current drive
programmability for output
data pins
3.5 mA drive X X X
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Table 6: Summary of functions supported by the serial interface
Name Description Default D15 D14 D13 D12 D11 D10 D9 D8 D7 D6 D5 D4 D3 D2 D1 D0 Address
In Hex
en_lvds_term
Enables internal
termination for LVDS
buffers
Termination disabled X
12
term_lclk
<2:0>
Programmable termination
for LCLKN and LCLKP
buffers
Termination disabled 1 X X X
term_frame
<2:0>
Programmable termination
for FCLKN and FCLKP
buffers
Termination disabled 1 X X X
term_dat
<2:0>
Programmable termination
for output data buffers Termination disabled 1 X X X
invert_ch
<8:1>
Swaps the polarity of the
analog input pins IPx is positive input X X X X X X X X 24
en_ramp
Enables a repeating full-
scale ramp pattern on the
outputs
Inactive X 0 0
25
dual_custom_
pat
Enables the mode
wherein the output toggles
between two dened
codes
Inactive 0 X 0
single_custom_
pat
Enables the mode wherein
the output is a constant
specied code
Inactive 0 0 X
bits_custom1
<13:0>
Bits for the single custom
pattern and for the rst
code of the dual custom
pattern. <0> is the LSB
Inactive X X X X X X X X X X X X X X 26
bits_custom2
<13:0>
Bits for the second code of
the dual custom pattern Inactive X X X X X X X X X X X X X X 27
gain_ch1
<3:0>
Programmable gain for
channel 1 0dB gain X X X X
2A
gain_ch2
<3:0>
Programmable gain for
channel 2 0dB gain X X X X
gain_ch3
<3:0>
Programmable gain for
channel 3 0dB gain X X X X
gain_ch4
<3:0>
Programmable gain for
channel 4 0dB gain X X X X
gain_ch5
<3:0>
Programmable gain for
channel 5 0dB gain X X X X
2B
gain_ch6
<3:0>
Programmable gain for
channel 6 0dB gain X X X X
gain_ch7
<3:0>
Programmable gain for
channel 7 0dB gain X X X X
gain_ch8
<3:0>
Programmable gain for
channel 8 0dB gain X X X X
phase_ddr
<1:0>
Controls the phase of
LCLK output relative to
data
90 degrees X X 42
pat_deskew Enables deskew pattern
mode Inactive 0 X 45
pat_sync Enables sync pattern
mode Inactive X 0
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Table 6: Summary of functions supported by the serial interface
Name Description Default D15 D14 D13 D12 D11 D10 D9 D8 D7 D6 D5 D4 D3 D2 D1 D0 Address
In Hex
btc_mode
Binary two’s complement
format for ADC output
data
Straight offset binary X
46
msb_rst
Serialized ADC output
data comes out with MSB
rst
LSB-rst output X
en_sdr
Enable SDR output mode.
LCLK becomes a 12X/14X
input clock
DDR output mode X
fall_sdr
Rising edge of LCLK
comes in the middle of the
data window in SDR mode
Rising edge X 1
perfm_cntrl
<2:0> ADC performance control Nominal X X X
50
ext_vcm_bc
<1:0>
VCM buffer driving
strength control Nominal X X
lvds_pd_mode Controls LVDS power
down mode High z mode X 52
lvds_num_bits Sets the number of LVDS
output bits 12 bit X
53
lvds_advance
Advance LVDS data bits
and frame clock by one
clock cycle
Inactive 0 X
lvds_delay
Delay LVDS data bits and
frame clock by one clock
cycle
Inactive X 0
fs_cntrl
<5:0>
Fine adjust ADC full scale
range 0% change X X X X X X 55
clk_freq
<1:0> Input clock frequency 65 MHz X X 56
Description of Serial Registers
Software Reset
Name Description Default D15 D14 D13 D12 D11 D10 D9 D8 D7 D6 D5 D4 D3 D2 D1 D0 Address
In Hex
rst Self-clearing
software reset Inactive X 0
Setting the rst register bit to ‘1’, resets all internal registers including the rst register bit itself.
Power-Down Modes
Name Description Default D15 D14 D13 D12 D11 D10 D9 D8 D7 D6 D5 D4 D3 D2 D1 D0 Address
In Hex
pd_ch
<8:1>
Channel-specic
power-down. Inactive X X X X X X X X
0F
sleep Go to sleep-mode. Inactive X
pd Go to power-down. Inactive X
pd_pin_cfg
<1:0>
Congures the PD
pin for sleep-modes.
PD pin congured
for power-down
mode
X X
lvds_pd_mode Controls LVDS
power down mode High z mode X 52
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There are several ways to power down HMCAD1102, from sleep modes with short start up time to full power down with
extremely low power dissipation. There are two sleep modes, both with the LVDS clocks (FCLK, LCLK) running, such
that the synchronization with the receiver is maintained. The rst is a light sleep mode (pd_ch<8:1>) with short start
up time, and the second a deep sleep mode (sleep) with the same start up time as full power down.
Setting pd_ch<n> = ‘1’, sets channel <n> of the ADC in sleep mode. This is a light sleep mode with short start up time.
Setting sleep = ‘1’, powers down all channels, but keeps FCLK and LCLK running to maintain LVDS synchronization.
The start up time is the same as for complete power down. Power consumption is signicantly lower than for setting
pd_ch<8:1>=’FFhex’.
Setting pd = ‘1’ completely powers down the chip, including the band-gap reference circuit. Start-up time from this
mode is signicantly longer than from the pd_ch<n> mode. The synchronization with the LVDS receiver is lost since
LCLK and FCLK outputs are put in high-Z mode.
Setting pdn_pin_cfg<1:0> = ‘x1’ congures the circuit to enter sleep channel mode (all channels off) when the PD pin
is set high. This is equal to setting pd_ch<8:1>=’FFhex’. The channels can not be powered down separately using
the PD pin. Setting pdn_pin_cfg<1:0> = ‘10’ congures the circuit to enter (deep) sleep mode when PD pin is set high
(equal to setting sleep=’1’. When pdn_pin_cfg <1:0>= ‘00’, which is the default, the circuit enters power down mode
when the PD pin is set high.
The lvds_pd_mode register congures whether the LVDS data output drivers are powered down or kept alive in sleep
and sleep channel modes. LCLK and FCLK drivers are not affected by this register, and are always on in sleep and
sleep channel modes. If lvds_pd_mode is set low (default), the LVDS output is put in high Z mode, and the driver is
completely powered down. If lvds_pd_mode is set high, the LVDS output is set to constant 0, and the driver is still on
during sleep and sleep channel modes.
LVDS Drive Strength Programmability
Name Description Default D15 D14 D13 D12 D11 D10 D9 D8 D7 D6 D5 D4 D3 D2 D1 D0 Address
In Hex
ilvds_lclk
<2:0>
LVDS current drive
programmability for LCLKP
and LCLKN pins.
3.5 mA drive X X X
11
ilvds_frame
<2:0>
LVDS current drive
programmability for FCLKP
and FCLKN pins.
3.5 mA drive X X X
ilvds_dat
<2:0>
LVDS current drive
programmability for output
data pins.
3.5 mA drive X X X
The current delivered by the LVDS output drivers can be congured as shown in table 7. The default current is 3.5 mA,
which is what the LVDS standard species.
Setting the ilvds_lclk<2:0> register controls the current drive strength of the LVDS clock output on the LCLKP and
LCLKN pins.
Setting the ilvds_frame<2:0> register controls the current drive strength of the frame clock output on the FCLKP and
FCLKN pins.
Setting the ilvds_dat<2:0> register controls the current drive strength of the data outputs on the D[8:1]P and D[8:1]N
pins.
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Table 7: LVDS Output Drive
Strength for LCLK, FCLK and Data
ilvds_*<2:0> LVDS drive strength
000 3.5 mA (default)
001 2.5 mA
010 1.5 mA
011 0.5 mA
100 7.5 mA
101 6.5 mA
110 5.5 mA
111 4.5 mA
LVDS Internal Termination Programmability
Name Description Default D15 D14 D13 D12 D11 D10 D9 D8 D7 D6 D5 D4 D3 D2 D1 D0 Address
In Hex
en_lvds_
term
Enables internal termination
for LVDS buffers
Termination
disabled X
12
term_lclk
<2:0>
Programmable termination for
LCLKN and LCLKP buffers
Termination
disabled 1 X X X
term_frame
<2:0>
Programmable termination for
FCLKN and FCLKP buffers
Termination
disabled 1 X X X
term_dat
<2:0>
Programmable termination for
DxP and DxN buffers
Termination
disabled 1 X X X
The off-chip load on the LVDS buffers may represent a characteristic impedance that is not perfectly matched with
the PCB traces. This may result in reections back to the LVDS outputs and loss of signal integrity. This effect can be
mitigated by enabling an internal termination between the positive and negative outputs of each LVDS buffer. Internal
termination mode can be selected by setting the en_lvds_term bit to ‘1’. Once this bit is set, the internal termination
values for the bit clock, frame clock, and data buffers can be independently programmed using sets of three bits. Table
8 shows how the internal termination of the LVDS buffers are programmed. The values are typical values and can vary
by up to ±20% from device to device and across temperature.
Table 8: LVDS Output Internal
Termination for LCLK, FCLK and Data
term_*<2:0> LVDS Internal Termination
0 Termination disabled
1 280
10 165
11 100
100 125
101 82
110 67
111 56
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Analog Input Invert
Name Description Default D15 D14 D13 D12 D11 D10 D9 D8 D7 D6 D5 D4 D3 D2 D1 D0 Address
In Hex
invert_ch
<8:1>
Swaps the polarity of
the analog input pins
IPx is
positive
input
X X X X X X X X 24
The IPx pin represents the positive analog input pin, and INx represents the negative (complementary) input. Setting
the bits marked invert_ch<8:1> (individual control for each channel) causes the inputs to be swapped. INx would then
represent the positive input, and IPx the negative input.
LVDS Test Patterns
Name Description Default D15 D14 D13 D12 D11 D10 D9 D8 D7 D6 D5 D4 D3 D2 D1 D0 Address
In Hex
en_ramp
Enables a repeating full-
scale ramp pattern on the
outputs
Inactive X 0 0
25
dual_custom_
pat
Enables the mode wherein
the output toggles between
two dened codes
Inactive 0 X 0
single_
custom_pat
Enables the mode wherein
the output is a constant
specied code
Inactive 0 0 X
bits_custom1
<13:0>
Bits for the single custom
pattern and for the rst
code of the dual custom
pattern. <0> is the LSB
Inactive X X X X X X X X X X X X X X 26
bits_custom2
<13:0>
Bits for the second code of
the dual custom pattern Inactive X X X X X X X X X X X X X X 27
pat_deskew Enables deskew pattern
mode Inactive 0 X
45
pat_sync Enables sync pattern mode Inactive X 0
To ease the LVDS synchronization setup of HMCAD1102, several test patterns can be set up on the outputs.
Normal ADC data are replaced by the test pattern in these modes. Setting en_ramp to ‘1’ sets up a repeating full-scale
ramp pattern on all data outputs. The ramp starts at code zero and is increased 1LSB every clock cycle. It returns to
zero code and starts the ramp again after reaching the full-scale code.
A constant value can be set up on the outputs by setting single_custom_pat to ‘1’, and programming the desired value
in bits_custom1<13:0>. In this mode, bits_custom1<13:0> replaces the ADC data at the output, and is controlled by
LSB-rst and MSB-rst modes in the same way as normal ADC data are.
The device may also be made to alternate between two codes by programming dual_custom_pat to ‘1’. The two codes
are the contents of bits_custom1<13:0> and bits_custom2<13:0>. Two preset patterns can also be selected:
1. Deskew pattern: Set using pat_deskew, this mode replaces the ADC output with ‘01010101010101’ (two
LSBs removed in 12 bit mode).
2. Sync pattern: Set using pat_sync, the normal ADC word is replaced by a xed ‘11111110000000’ word
(‘111111000000’ in 12 bit mode)
Note: Only one of the above patterns should be selected at the same time.
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Programmable Gain
Name Description Default D15 D14 D13 D12 D11 D10 D9 D8 D7 D6 D5 D4 D3 D2 D1 D0 Address
In Hex
gain_ch1
<3:0>
Programmable gain
for channel 1 0 dB gain X X X X
2A
gain_ch2
<3:0>
Programmable gain
for channel 2 0 dB gain X X X X
gain_ch3
<3:0>
Programmable gain
for channel 3 0 dB gain X X X X
gain_ch4
<3:0>
Programmable gain
for channel 4 0 dB gain X X X X
gain_ch5
<3:0>
Programmable gain
for channel 5 0 dB gain X X X X
2B
gain_ch6
<3:0>
Programmable gain
for channel 6 0 dB gain X X X X
gain_ch7
<3:0>
Programmable gain
for channel 7 0 dB gain X X X X
gain_ch8
<3:0>
Programmable gain
for channel 8 0 dB gain X X X X
HMCAD1102 includes a purely digital programmable gain option in addition to the Full-scale Control. The programmable
gain of each channel can be individually set using four bits, indicated as gain_chx<3:0> for Channel x. The gain
setting is coded in binary from 0 dB to 12 dB, as shown in Table 9.
Table 9: Gain setting for channels 1-8
gain_chx <3:0> Channel x Gain Setting
0000 0 dB
0001 1 dB
0010 2 dB
0011 3 dB
0100 4 dB
0101 5 dB
0110 6 dB
0111 7 dB
1000 8 dB
1001 9 dB
1010 10 dB
1011 11 dB
1100 12 dB
1101 Do not use
1110 Do not use
1111 Do not use
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LVDS Clock Programmability and Data Output Modes
Name Description Default D15 D14 D13 D12 D11 D10 D9 D8 D7 D6 D5 D4 D3 D2 D1 D0 Address
In Hex
phase_ddr
<1:0>
Controls the phase of LCLK
output relative to data. 90 degrees. X X 42
btc_mode Binary two’s complement format
for ADC output data.
Straight offset
binary. X
46
msb_rst Serialized ADC output data
comes out with MSB rst.
LSB-rst
output. X
en_sdr Enable SDR output mode. LCLK
becomes a 12X input clock.
DDR output
mode. X
fall_sdr
Controls whether the LCLK rising
or falling edge comes in the
middle of the data window when
operating in SDR mode.
Rising edge of
LCLK comes
in the middle
of the data
window.
X 1
The output interface of HMCAD1102 is normally a DDR interface, with the LCLK rising and falling edge transitions
in the middle of alternate data windows. The phase for LCLK can be programmed relative to the output frame clock
and data bits using phase_ddr<1:0>. The LCLK phase modes are shown in gure 9. The default timing is identical to
setting phase_ddr<1:0>=’10’.
FCLKN
FCLKP
LCLKP
LCLKN
Dxx<1:0>
FCLKN
FCLKP
LCLKP
LCLKN
Dxx<1:0>
FCLKN
FCLKP
LCLKP
LCLKN
Dxx<1:0>
FCLKN
FCLKP
LCLKP
LCLKN
Dxx<1:0>
PHASE_DDR<1:0>='00' (270 deg)
PHASE_DDR<1:0>='10' (90 deg)
PHASE_DDR<1:0>='01' (180 deg)
PHASE_DDR<1:0>='11' (0 deg)
Figure 8. Phase programmability modes for LCLK
The device can also be made to operate in SDR mode by setting the en_sdr bit to ‘1’. The bit clock (LCLK) is output
at 12x times the input clock in this mode, two times the rate in DDR mode. Depending on the state of fall_sdr, LCLK
may be output in either of the two manners shown in Figure 10. As can be seen in Figure 10, only the LCLK rising (or
falling) edge is used to capture the output data in SDR mode. The SDR mode is not recommended beyond 40 MSPS
because the LCLK frequency becomes very high.
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FCLKN
FCLKP
LCLKP
LCLKN
Dxx<1:0>
FCLKN
FCLKP
LCLKP
LCLKN
Dxx<1:0>
EN_SDR='1', FALL_SDR_'0' EN_SDR='1', FALL_SDR_'1'
Figure 9. SDR interface modes
The default data output format is offset binary. Two’s complement mode can be selected by setting the btc_mode bit
to ‘1’ which inverts the MSB.
The rst bit of the frame (following the rising edge of FCLKP) is the LSB of the ADC output for default settings.
Programming the msb_rst mode results in reverse bit order, and the MSB is output as the rst bit following the
FCLKP rising edge.
Number of Serial Output Bits and LVDS output timing
Name Description Default D15 D14 D13 D12 D11 D10 D9 D8 D7 D6 D5 D4 D3 D2 D1 D0 Address
In Hex
lvds_num_bits Sets the number of LVDS
output bits 12 bit X
53
lvds_advance
Advance LVDS data bits
and frame clock by one
clock cycle
Inactive 0 X
lvds_delay
Delay LVDS data bits and
frame clock by one clock
cycle
Inactive X 0
The ADC channels have 13 bits of resolution. There are two options for the serial LVDS outputs, 12 bits or 14 bits,
selected by setting lvds_num_bits to ‘0’ or ‘1’, respectively. In 12 bits mode, the LSB bit from the ADCs are removed
in the output stream. In 14 bit mode, a ‘0’ is added in the LSB position. Power down mode must be activated after or
during a change in the number of output bits.
To ease timing in the receiver when using multiple ADC chips, HMCAD1102 has the option to adjust the timing of the
output data and the frame clock. The propagation delay with respect to the ADC input clock can be moved one LVDS
clock cycle forward or backward, by using lvds_delay and lvds_advance, respectively. See gure 11 for details. Note
that LCLK is not affected by lvds_delay or lvds_advance settings.
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D3 D4 D5 D6 D7 D8 D9 D10 D11 D0 D1 D2 D3 D4 D5 D6 D7 D8 D9
NNNNNNNNNN
N-1 N-1 N-1 N-1 N-1 N-1 N-1 N-1 N-1
ADC clock
LCLKP
LCLKN
FCLKP
FCLKN
Dxx<1:0>
D0 D1 D2 D3 D4 D5 D6 D7 D8
N N N N N N N N NN-1 N-1 N-1 N-1 N-1 N-1 N-1 N-1 N-1 N-1
FCLKP
FCLKN
Dxx<1:0>
D4 D5 D6 D7 D8 D9 D10 D11 D0 D1 D2 D3 D4 D5 D6 D7 D8 D9 D10
N N N N N N N N N N NN-1 N-1 N-1 N-1 N-1 N-1 N-1 N-1
FCLKP
FCLKN
Dxx<1:0>
lvds_delay = '1':
lvds_advance = '1':
default:
TLVDS
D2 D3 D4 D5 D6 D7 D8 D9 D10 D11
TLVDS
TLVDS
TPROP
TPROP
TPROP
Figure 10. LVDS output timing adjustment
Full-Scale Control
Name Description Default D15 D14 D13 D12 D11 D10 D9 D8 D7 D6 D5 D4 D3 D2 D1 D0 Address
In Hex
fs_cntrl
<5:0>
Fine adjust ADC full
scale range
0%
change X X X X X X 55
The full-scale voltage range of HMCAD1102 can be adjusted using an internal 6-bit DAC controlled by the fs_cntrl
register. Changing the value in the register by one step, adjusts the full-scale range by approximately 0.3%. This
leads to a maximum range of ±10% adjustment. Table 10 shows how the register settings correspond to the full-scale
range. Note that the values for full-scale range adjustment are approximate. The DAC is, however, guaranteed to be
monotonous.
The full-scale control and the programmable gain features differ in two major ways:
1. The full-scale control feature controls the full-scale voltage range in an analog fashion, whereas the
programmable gain is a digital feature.
2. The programmable gain feature has much coarser gain steps and larger range than the full-scale control.
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Table 10: Register Values with
Corresponding Change in Full-Scale Range
fs_cntrl<5:0> Full-scale range adjustment
111111 9.70%
111110 9.40%
100001 0.30%
100000 0%
011111 −0.3%
000001 −9.7%
000000 −10%
To optimize start up time, a register is provided where the input clock frequency can be set. Some internal circuitry
have start up times that are clock frequency independent. Default counter values are set to accommodate these start
up times at the maximum clock frequency. This will lead to increased start up times at low clock frequency. Setting
the value of this register to the nearest higher clock frequency will reduce the count values of the internal counters,
to better t the actual start up time, such that the start up time will be reduced. The start up times from Power Down
mode and Deep Sleep mode are changed by this register setting.
Table 11: Clock frequency settings
clk_freq
<1:0>
Clock frequency
range
Startup delay
(clock cycles) Startup delay (µs)
0 0 50 - 80 MHz 992 12.4 - 19.8
0 1 32.5 - 50 MHz 640 12.8 - 19.7
1 0 20 - 32.5 MHz 420 12.9 - 21
1 1 15 - 20 MHz 260 13 - 17.3
Performance Control
Name Description Default D15 D14 D13 D12 D11 D10 D9 D8 D7 D6 D5 D4 D3 D2 D1 D0 Address
In Hex
perfm_cntrl
<2:0>
ADC performance
control Nominal X X X
50
ext_vcm_bc
<1:0>
VCM buffer driving
strength control Nominal X X
There are two registers that impact performance and power dissipation.
The perfm_cntrl register adjusts the performance level of the ADC core. If full performance is required, the nominal
setting must be used. The lowest code can be used in situations where power dissipation is critical and performance
is less important. For most conditions the performance at the minimum setting will be similar to nominal setting.
However, only 11 bit performance can be expected at worst case conditions. The power dissipation savings shown in
table 12 are only approximate numbers for the ADC current alone.
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Table 12: Performance Control Settings
perfm_cntrl<2:0> Analog power dissipation
100 -40% (lower performance)
101 -30%
110 -20%
111 -10%
000 (default) Nominal
001 Do not use
010 Do not use
011 Do not use
The ext_vcm_bc register controls the driving strength in the buffer supplying the voltage on the VCM pin. If this pin is
not in use, the buffer can be switched off. If current is drawn from the VCM pin, the driving strength can be increased
to keep the voltage on this pin at the correct level.
Table 13: External Common
Mode Voltage Buffer Driving Strength
ext_vcm_bc
<1:0>
VCM buffer driving strength [µA] Max current
sinked/sourced from VCM pin with < 50 mV
voltage change.
00 Off (VCM oating)
01 (default) ±6.5
10 ±70
11 ±140
Theory of Operation
HMCAD1102 is an 8-channel, high-speed, CMOS
ADC. The outputs from each channel are serialized
to 12 or 14 bits and sent out on a single pair of pins
in LVDS format. All eight channels of HMCAD1102
operate from one clock input, which can be differential
or single ended. The sampling clocks for each of the
eight channels are generated from the clock input
using a carefully matched clock buffer tree. The 12x
clock required for the serializer is generated internally
from FCLK using a phase-locked loop (PLL). A 6x and
1x clock are also output in LVDS format, along with
the data to enable easy data capture. HMCAD1102
uses internally generated references. The differential
reference value is 1V. This results in a differential input
of −1V to correspond to the zero code of the ADC, and
a differential input of +1V to correspond to the full-
scale code (code 8191).
The ADC employs a pipelined converter architecture.
Each stage feeds its output data into the digital error
correction logic, ensuring excellent differential linearity
and no missing codes at 12-bit level.
HMCAD1102 operates from two sets of supplies
and grounds. The analog supply and ground set is
identied as AVDD and AVSS, while the digital set is
identied by DVDD and DVSS.
Recommended Usage
Analog Input
The analog input to HMCAD1102 is a switched
capacitor track-and-hold amplier optimized for
differential operation. Operation at common mode
voltages at mid supply is recommended even if
performance will be good for the ranges specied.
The VCM pin provides a voltage suitable as common
mode voltage reference. The internal buffer for
the VCM voltage can be switched off, and driving
capabilities can be changed programming the ext_
vcm_bc<1:0> register.
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Figure 11. Input conguration
Figure 12 shows a simplied drawing of the input
network. The signal source must have sufficiently low
output impedance to charge the sampling capacitors
within one clock cycle. A small external resistor (e.g.
22 Ohm) in series with each input is recommended
as it helps reducing transient currents and dampens
ringing behavior. A small differential shunt capacitor
at the chip side of the resistors may be used to
provide dynamic charging currents and may improve
performance. The resistors form a low pass lter
with the capacitor, and values must therefore be
determined by requirements for the application.
DC-Coupling
Figure 13 shows a recommended conguration for
DC-coupling. Note that the common mode input
voltage must be controlled according to specied
values. Preferably, the CM_EXT output should be
used as reference to set the common mode voltage.
Figure 12. DC coupled input
The input amplier could be inside a companion chip
or it could be a dedicated amplier. Several suitable
single ended to differential driver ampliers exist in the
market. The system designer should make sure the
specications of the selected amplier is adequate for
the total system, and that driving capabilities comply
with HMCAD1102 input specications.
Detailed conguration and usage instructions must be
found in the documentation of the selected driver, and
the values given in gure 13 must be varied according
to the recommendations for the driver.
AC-Coupling
A signal transformer or series capacitors can be
used to make an AC-coupled input network. Figure
14 shows a recommended conguration using a
transformer. Make sure that a transformer with
sufficient linearity is selected, and that the bandwidth
of the transformer is appropriate. The bandwidth
should exceed the sampling rate of the ADC with at
least a factor of 10. It is also important to minimize
phase mismatch between the differential ADC inputs
for good HD2 performance. This type of transformer
coupled input is the preferred conguration for high
frequency signals as most differential ampliers do
not have adequate performance at high frequencies.
Magnetic coupling between the transformers and PCB
traces may impact channel crosstalk, and must hence
be taken into account during PCB layout.
Figure 13. Transformer coupled input
If the input signal is traveling a long physical distance
from the signal source to the transformer (for example
a long cable), kick-backs from the ADC will also
travel along this distance. If these kick-backs are
not terminated properly at the source side, they are
reected and will add to the input signal at the ADC
input. This could reduce the ADC performance. To
avoid this effect, the source must effectively terminate
the ADC kick-backs, or the traveling distance should
be very short. If this problem could not be avoided, the
circuit in gure 16 can be used.
Figure 14. AC coupled input
Figure 15 shows AC-coupling using capacitors.
Resistors from the CM_EXT output, RCM, should be
used to bias the differential input signals to the correct
voltage. The series capacitor, CI, form the high-
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pass pole with these resistors, and the values must
therefore be determined based on the requirement to
the high-pass cut-off frequency.
Note that Start Up Time from Sleep Mode and Power
Down Mode will be affected by this lter as the time
required to charge the series capacitors is dependent
on the lter cut-off frequency.
If the input signal has a long traveling distance, and the
kick-backs from the ADC are not effectively terminated
at the signal source, the input network of gure 16 can
be used. The conguration in gure 16 is designed to
attenuate the kickback from the ADC and to provide
an input impedance that looks as resistive as possible
for frequencies below Nyquist.
Figure 15. Alternative input network
Values of the series inductor will however depend on
board design and conversion rate. In some instances
a shunt capacitor in parallel with the termination
resistor (e.g. 33pF) may improve ADC performance
further. This capacitor attenuate the ADC kick-back
even more, and minimize the kicks traveling towards
the source. However, the impedance match seen into
the transformer becomes worse.
Clock Input and Jitter Considerations
Typically high-speed ADCs use both clock edges to
generate internal timing signals. In HMCAD1102 only
the rising edge of the clock is used. Hence, input clock
duty cycles between 20% and 80% are acceptable.
The input clock can be supplied in a variety of formats.
The clock pins are AC-coupled internally, hence a wide
common mode voltage range is accepted. Differential
clock sources such as LVDS, LVPECL or differential
sine wave can be connected directly to the input pins.
For CMOS inputs, the CLKN pin should be connected
to ground, and the CMOS clock signal should be
connected to CLKP. For differential sine wave clock
input the amplitude must be at least ± 0.8 Vpp. No
additional conguration is needed to set up the clock
source format.
The quality of the input clock is extremely important for
high-speed, high-resolution ADCs. The contribution to
SNR from clock jitter with a full scale signal at a given
frequency is shown in equation 1.
SNRjitter = 20 · log (2 · π · ƒIN · єt) (1)
where fIN is the signal frequency, and εt is the total
rms jitter measured in seconds. The rms jitter is the
total of all jitter sources including the clock generation
circuitry, clock distribution and internal ADC circuitry.
For applications where jitter may limit the obtainable
performance, it is of utmost importance to limit the clock
jitter. This can be obtained by using precise and stable
clock references (e.g. crystal oscillators with good jitter
specications) and make sure the clock distribution
is well controlled. It might be advantageous to use
analog power and ground planes to ensure low noise
on the supplies to all circuitry in the clock distribution.
It is of utmost importance to avoid crosstalk between
the ADC output bits and the clock and between the
analog input signal and the clock since such crosstalk
often results in harmonic distortion.
The jitter performance is improved with reduced rise
and fall times of the input clock. Hence, optimum jitter
performance is obtained with LVDS or LVPECL clock
with fast edges. CMOS and sine wave clock inputs will
result in slightly degraded jitter performance.
If the clock is generated by other circuitry, it should
be re-timed with a low jitter master clock as the last
operation before it is applied to the ADC clock input.
For price, delivery and to place orders: Hittite Microwave Corporation, 2 Elizabeth Drive, Chelmsford, MA 01824
978-250-3343 tel • 978-250-3373 fax • Order On-line at www.hittite.com
Application Support: apps@hittite.com
A / D CONVERTERS - SMT
0
0 - 240 - 24
HMCAD1102
v03.0611
OCTAL 12-BIT 80 MSPS
A/D CONVERTER
Outline Drawing
Table 14: Dimensions
Symbol Millimeter Inch
Min Typ Max Min Typ Max
A 0.9 0.035
A1 0 0.01 0.05 0 0.0004 0.002
A2 0.65 0.7 0.026 0.028
A3 0.2 REF. 0.008 REF.
b 0.2 0.25 0.3 0.008 0.01 0.012
D 9.00 bsc 0.354 bsc
D1 8.75 bsc 0.344 bsc
D2 5 5.2 5.4 0.197 0.205 0.213
L 0.3 0.4 0.5 0.012 0.016 0.02
e 0.50 bsc 0.020 bsc
Θ1 0° 12° 0° 12°
F 1.3 0.05
G 0.24 0.42 0.6 0.0096 0.0168 0.024
Package Information
Part Number Package Body Material Lead Finish MSL [1] Package Marking [2]
HMCAD1102 RoHS-compliant Low Stress Injection Molded Plastic 100% matte Sn Level 2A HAD1102
XXXX
[1] MSL, Peak Temp: The moisture sensitivity level rating classied according to the JEDEC industry standard and to peak solder temperature.
[2] Proprietary marking XXXX, 4-Digit lot number XXXX