Analog Devices EVAL-AD7450A, Руководство пользователя

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Evaluation Board User Guide EVAL-AD7450A/EVAL-AD7451
Rev. A | Page 11 of 28
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
REF
to −V
REF
.
LK4 is inserted.
For unipolar signals, the input should be 0 V to V
REF
. LK4 is
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 V
IN+
and V
IN−
inputs
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
IN+
input via low-pass RC filter network.
REFERENCE OPTIONS
The reference source can be from an ADR431 ultralow noise
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 A Input. This is routed to a selection of input
buffers.
J2
INPUT B Input. This is routed to a selection of input
buffers.
J3
EXT_REF External reference connection point.
J4 EVAL-SDP-CB1Z evaluation board controller
socket.
J100
VSS and VDD Screw terminal connectors for external
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
VCC External power supply for V
DD
of the
AD7450A / AD7451 .