Datasheet

EVAL-AD5422
Rev. 0 | Page 3 of 12
EVALUATION BOARD HARDWARE
POWER SUPPLIES
The following external supplies must be provided:
• 5 V between the 5 V and 0 V inputs for the digital supply
of the AD5422 and digital circuitry. Alternatively, place
Link 6 in Position A to power the digital circuitry from the
USB port (default).
• 10.8 V to 40 V between the AV
DD
and GND inputs for the
analog supply of the AD5422.
• 0 V to −26.4 V between the AV
SS
and GND inputs for the
negative analog supply of the AD5422. (This is only required
if a bipolar output voltage range is to be programmed;
otherwise, the negative supply of the AD5422 can be
connected to GND by placing Link 4 in Position A.)
• 10.8 V to 16.5 V between the V+ and GND inputs for the
analog supply of the AD7321 (on-board ADC) and ADR435
(on-board voltage reference). If the analog supply connected
to the AV
DD
input is less than 16.5 V, the AD7321 and ADR435
can be powered from this by placing LK9 in Position A,
and the V+ input can be left unconnected.
• 0 V to −16.5 V between the V− and GND inputs for the
negative analog supply of the AD7321 (on-board ADC). If
the negative analog supply connected to the AV
SS
input is
less than (magnitude) −16.5 V, the AD7321 can be powered
from this by placing LK16 in Position A, and the V− input
can be left unconnected.
The analog and digital planes are connected at one location, close
to the AD5422. It is recommended not to connect GND and
DGND elsewhere in the system to avoid ground loop problems.
Each supply is decoupled to the relevant ground plane with 10 μF
and 0.1 μF capacitors. Each device supply pin is again decoupled
with a 10 μF and 0.1 μF capacitor pair to the relevant ground plane.
Excessive Power Supply
If a power supply in excess of +16.5 V is to be connected to
the AV
DD
input, LK9 must be in Position B to prevent potential
damage to the 5 V voltage reference or to the ADC (see U2 and
U6, respectively, in Figure 5). However, if a power supply in excess
of −16.5 V is to be connected to the AV
SS
input, LK16 must be
in Position B to prevent potential damage to the ADC.
LINK OPTIONS
The position of Link 7 configures the board for either PC
control via the USB port (default setup) or for control by an
external source via J8. The link options on the evaluation board
should be set for the required operating setup before using the
board. The functions of the link options are described in Table 4 .
Default Link Option Setup
The default setup is for control by the PC via the USB port. The
default link options are listed in Table 1.
Table 1. Link and Switch Defaults (PC Control)
Link No. Option
LK1 A
LK2 A
LK3 Inserted
LK4 B
LK5 B
LK6 A
LK7 A
LK8 A
LK9 A
LK10 Inserted
LK11 Inserted
LK12 Inserted
LK13 Inserted
LK14 Inserted
LK15 C
LK16 A
LK17 Inserted
LK18 Inserted
Connector J8 Pin Descriptions
Table 2. Connector J8 Pin Configuration
1
2 4 6 8 10
1 3 5 7 9
1
LK7 must be in Position B to enable the use of J8.
Table 3. Connector J8 Pin Descriptions
Connector J8 Pin No. Function
1 SDO
2 CLEAR SELECT
3 DGND
4 CLEAR
5 DGND
6
FAU LT
7 SDIN
8 DGND
9 SCLK
10 LATCH