Datasheet

Evaluation Board User Guide UG-184
Rev. 0 | Page 3 of 16
EVALUATION BOARD HARDWARE
POWER SUPPLIES
The following external supplies must be provided:
• 5 V between the V
CC
and DGND inputs for the digital
supply of the AD5781. Alternatively, place Link 1 in
Position A to power the digital circuitry from the USB
port (default).
• 7.5 V to 16.5 V between the V
DD
and AGND inputs for the
positive analog supply of the AD5781.
• −2.5 V to −16.5 V between the V
SS
and AGND inputs for
the negative analog supply of the AD5781.
The analog and digital planes are connected at one location,
close to the AD5781. To avoid ground loop problems, it is
recommended not to connect AGND and DGND elsewhere
in the system.
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.
LINK OPTIONS
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 5.
Default Link Option Setup
The default link options are listed in Table 1.
Table 1. Default Link Options
Link No. Option
LK1 A
LK3 A
LK4 Removed
LK5 Removed
LK6 Removed
LK8 A
LK9 C
Connector J6 Pin Descriptions
Table 2. Connector J6 Pin Configuration
9 7 5 3 1
10 8 6 4 2
Table 3. Connector J6 Pin Descriptions
Pin No. Description
1 SDO
2
RESET
3 DGND
4
CLR
5 IOVCC
6
LDAC
7 SDIN
8 DGND
9 SCLK
10
SYNC
ON-BOARD CONNECTORS
There are nine connectors on the AD5781 evaluation board
PCB as outlined in Table 4.
Table 4. On-Board Connectors
Connector Function
J1 Analog power supply connector
J2 Digital power supply connector
J3 SDP board connector
J6 Digital interface pin header connector
VOUT DAC output connector
VOUT_BUF Buffered DAC output connector
VREF
5 V voltage reference input connector (+10 V
and −10 V reference voltages are generated
from 5 V input)
VREFN DAC negative reference input connector
VREFP DAC positive reference input connector