Evaluation Board Circuitry; Analog Inputs; Reference Options; Sockets/Connectors - Analog Devices EVAL-AD7450A User Manual

Evaluation Board User Guide

EVALUATION BOARD CIRCUITRY

ANALOG INPUTS

Three buffer circuits are available as follows.
Single-Ended to Differential
A single input signal applied to the INPUT A SMB socket can
be used to generate a differential signal.
For bipolar signals, the input range should be +V
LK4 is inserted.
For unipolar signals, the input should be 0 V to V
removed.
Individual Channel Buffers
INPUT A and INPUT B are used in this configuration. Both
inputs are buffered individually. The outputs from these ampli-
fiers are available to the AD7450A/AD7451
via low-pass RC filter networks.
Level Shifter
The analog inputs on the EVAL-AD7450ASDZ/EVAL-
AD7451SDZ are filtered and buffered by an AD8599. The
outputs from this amplifier are available to the AD7450A/
AD7451 V input via low-pass RC filter network.
IN+
to −V .
REF REF
. LK4 is
REF
V and V inputs
IN+ IN−
Rev. A | Page 11 of 28
EVAL-AD7450A/EVAL-AD7451

REFERENCE OPTIONS

The reference source can be from an
XFET® voltage references with current sink and source capability
(U2). An external reference voltage may also be applied to J3
EXT_REF.

SOCKETS/CONNECTORS

Table 5. Socket Connector Functions
Socket Function
J1 Input. This is routed to a selection of input
INPUT A buffers.
J2 Input. This is routed to a selection of input
INPUT B buffers.
J3 External reference connection point.
EXT_REF
J4 EVAL-SDP-CB1Z
socket.
J100 Screw terminal connectors for external
VSS and VDD amplifier power supplies.
J700 7 V to 9 V bench supply screw terminal
connector.
J702 7 V to 9 V dc transformer power connector.
J703 External power supply for V
VCC AD7450A/AD7451.
ADR431 ultralow noise
evaluation board controller
of the
DD