Analog Inputs And Front-End Circuit - Analog Devices EVAL-AD7761FMCZ User Manual

UG-949

ANALOG INPUTS AND FRONT-END CIRCUIT

As shown in Figure 2, the AIN0± to AIN7± analog inputs are
accessible through either the SMBs or the terminal blocks.
Figure 2 shows theses connectors and details the 16 main solder
links that route the inputs from either the terminal blocks or the
SMBs for each of the signals.
In the default board configuration, the input terminals are
connected through to the
channels.
TERMINAL
BLOCKS
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ADA4896-2 on each of the ADC
SMB CONNECTORS
J8, J13
SOLDER LINK TYPES TO ROUTE ANALOG INPUTS TO ADC INPUTS
J8
CH7
SOLDER LINKS
SL7+, SL7, SL6+, SL6–, SL4+, SL4–, SL3+, SL3–, SL2+, SL2–, SL1+, SL1–, SL0+, SL0–
FOR CHANNEL 7,CHANNEL 6, CHANNEL 4, CHANNEL 3,
CH6
CHANNEL 2, CHANNEL 1, CHANNEL 0
CH5
A
CH4
CH0
CH1
A
CH2
CH3
J13
C
Figure 2. Analog Inputs: Input Connectors, Solder Links, and Amplifiers
The ADR444
allowing an absolute input range of 0||4.096 V on each input.
The ADA4896-2
any particular source impedances.
Use the on-board, common-mode voltage source on the
to bias the input signal. The default condition is V
(AVDD1 − AVSS)/2.
B
DIRECT TO ADC INPUT
TO ADC INPUT VIA ADA4896-2,
G = 1 (DEFAULT)
8 × ADA4896-2
SOLDER LINKS:
ADR444
SL5 + 1, SL5 – 1
FOR CHANNEL 5 ONLY
TO ADC INPUT VIA ADA4896-2, G = 1
B
DIRECT TO ADC INPUT
TO EXTERNAL AMPLIFIER DRIVER BOARD
Rev. 0 | Page 4 of 17
EVAL-AD7761FMCZ User Guide
4.096 V low noise reference is used by default,
amplifiers are not terminated at the inputs for
32MHz
CLOCK
ADC DATA
AD7761
SPI CONTROL
AD7761
=
CM