Evaluation Board User Guide

UG-459

Rev. 0 | Page 3 of 12

EVALUATION BOARD HARDWARE

POWER SUPPLIES

To use the evaluation board with the SDP board, a 6 V power

supply is required, which is connected to Connector J3. The

evaluation board can be used without the SDP board. In this case,

the J1 and J2 connectors are used as the power supply inputs.

Both AGND and DGND inputs are provided on the board. The

AGND and DGND planes are connected at one location close

to the AD568x(R). It is recommended that AGND and DGND

not be connected elsewhere in the system to avoid ground loop

problems.

All supplies are decoupled to ground with 10 µF tantalum and

0.1 µF ceramic capacitors.

Table 1. Power Supply Connectors

Connector Number

Voltage

J1

External, V

J2

Analog power supply, V

DD

J3

6 V board positive power supply

LINK OPTIONS

A number of link options are incorporated in the evaluation

board and must be set for the required operating conditions

before using the board. The functions of these link options are

described in detail in Table 3. Table 2 lists the positions of the

different links controlled by PC, via the USB port, and the SDP

board in single-supply mode is required.

Table 2. Link Options Setup for SDP Control (Default)

Link Number

Option

LK1

A

LK2

A

LK3

C

LK4

B

LK5

A

LK6

B

Table 3. Link Functions

Link Number

Option

LK1

This link selects the DAC analog voltage source.

Position A selects the internal voltage source (INT_VDD) from the ADP3331.

Position B selects an external supply voltage (EXT_VDD).

LK2

This link selects the DAC digital voltage source.

Position A selects the digital voltage source from the SDP board (V_IO).

Position B selects an external digital supply voltage (EXT_VLOGIC).

LK3

This link selects the reference source.

Position A selects the on-board 2.5 V reference as the reference source. Do not use this option with the AD5686R/AD5684R.

Position B selects the on-board 5 V reference as the reference source. Do not use this option with the AD5686R/AD5684R.

Position C selects the internal reference of the AD5686R/AD5684R as the reference source for the AD5686/AD5684.

Position D selects an off board voltage reference via the EXT_REF connector.

LK4

This link selects the gain setting of the AD5686/AD5684 (not populated).

Position A selects gain of 2.

Position B selects gain of 1.

LK5

This link selects the gain setting of the AD5686R/AD5684R.

Position A selects gain of 2.

Position B selects gain of 1.

LK6

This link selects whether the AD5686R/AD5684R or AD5686/AD5684 is accessed by the software.

Position A selects the AD5686/AD5684.

Position B selects the AD5686R/AD5684R.