Evaluation Board User Guide

UG-382

Rev. A | Page 3 of 8

EVALUATION BOARD HARDWARE

POWER SUPPLIES

AGND and DGND are connected together on the board to

provide a single GND signal. To power the EVAL-AD5700-1EBZ,

supply of the AD5700/AD5700-1. With L5 inserted (default), this

LINK OPTIONS

A number of links on the evaluation board must be set for the

required operating setup before using the board. The functions

of these link options are described in detail in Table 2. The

default setup is using the on-chip reference, the crystal

oscillator, and the internal receive filter (see Table 1).

Table 1. Default Link Options

Link No.

Option

CLK_CFG1

A

CLK_CFG0

A

XTAL_EN

A

FILTER_SEL

B

L1

A

L2

A

REF_EN

B

DUPLEX

A

L5

Inserted

L6

Not inserted

L8

Inserted

Table 2. Link Functions

Link No.

Function

CLK_CFG1,

CLK_CFG0,

XTAL_EN

The AD5700/AD5700-1 support numerous clocking configurations to allow a simple, low cost solution. The

AD5700/AD5700-1 can use an external crystal or ceramic resonator, a CMOS input, or an internal RC oscillator

(AD5700-1 only). The CLK_CFG0, CLK_CFG1, and XTAL_EN links configure the clock generation as follows:

XTAL_EN

CLK_CFG1

CLK_CFG0

CLKOUT

Description

B

A

A

No output

3.6864 MHz CMOS clock connected at XTAL1 pin

B

A

B

No output

1.2288 MHz CMOS clock connected at XTAL1 pin

B

B

A

No output

Internal oscillator enabled

B

B

B

1.2288 MHz output

Internal oscillator enabled, CLKOUT enabled

A

A

A

No output

Crystal oscillator enabled

A

A

B

3.6864 MHz output

Crystal oscillator enabled, CLKOUT enabled

A

B

A

1.8432 MHz output

Crystal oscillator enabled, CLKOUT enabled

A

B

B

1.2288 MHz output

Crystal oscillator enabled, CLKOUT enabled

FILTER_SEL, L1, L2

These link options set whether the internal or external receive band-pass filter is used at the HART input.

Setting FILTER_SEL to Position B and L1 and L2 to Position A sets the board to use the internal receive band-pass filter.

Setting FILTER_SEL to Position A and L1 and L2 to Position B sets the board to use the external receive band-pass filter.

REF_EN

This sets whether the internal or an external reference is used.

Position A—disables the internal reference, and a buffered external 2.5 V reference source must be applied at REF.

Position B—enables the internal 1.5 V reference and buffer.

DUPLEX

Allows the modulator and demodulator of the AD5700/AD5700-1 to be enabled at the same time.

Position A—the AD5700/AD5700-1 operate in half-duplex operation (controlled by RTS).

Position B—the AD5700/AD5700-1 operate in full duplex operation, with the modulator and demodulator of the

AD5700/AD5700-1 enabled at the same time.

L5

L6

Do not insert this link.

L8

This link must be inserted.