UG-949
EVAL-AD7761FMCZ User Guide
Rev. 0 | Page 4 of 17
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
ADA4896-2
on each of the ADC
channels.
The
ADR444
4.096 V low noise reference is used by default,
allowing an absolute input range of 0||4.096 V on each input.
The
ADA4896-2
amplifiers are not terminated at the inputs for
any particular source impedances.
Use the on-board, common-mode voltage source on the
AD7761
to bias the input signal. The default condition is V
CM
=
(AVDD1 − AVSS)/2.
TERMINAL
BLOCKS
J8, J13
J8
CH7
B
DIRECT TO ADC INPUT
TO ADC INPUT VIA ADA4896-2,
G = 1 (DEFAULT)
8 × ADA4896-2
TO ADC INPUT VIA ADA4896-2, G = 1
SOLDER LINKS:
SL5 + 1, SL5 – 1
FOR CHANNEL 5 ONLY
DIRECT TO ADC INPUT
ADC DATA
32MHz
CLOCK
A
SOLDER LINK TYPES TO ROUTE ANALOG INPUTS TO ADC INPUTS
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,
CHANNEL 2, CHANNEL 1, CHANNEL 0
J13
CH6
CH5
CH4
CH0
CH1
CH2
CH3
120-
P
IN CO
NNE
C
T
OR
T
O
SD
P
AD7761
ADR444
B
A
C
SPI CONTROL
14323-
002
TO EXTERNAL AMPLIFIER DRIVER BOARD
SMB CONNECTORS
Figure 2. Analog Inputs: Input Connectors, Solder Links, and Amplifiers
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