AD623-EVALZ

Rev. 0 | Page 3 of 4

APPENDIX

Table 2. Jumpers

Jumper

Function

Description

Status

W1

+GUARD select

Allows the shield of the positive input cable to be connected to the guard driver or ground

Not installed

W2

–GUARD select

Allows the shield of the negative input cable to be connected to the guard driver or ground

Not installed

W3

+Input coupling

Installed; the positive input is dc-coupled

Installed

W4

–Input coupling

Installed; the negative input is dc-coupled

Installed

W5

Guard driver –IN

Connects the negative shield guard driver to Pin 1 of the in-amp

Not installed

W6

Connects the negative supply voltage to the negative auxiliary voltage if of the same value

Not installed

W7

Connects the positive supply voltage to the positive auxiliary voltage if of the same value

Not installed

W8

Guard driver +IN

Connects the positive shield guard driver to Pin 8 of the in-amp

Not installed

W9

Guard driver +IN

Connects the positive shield guard driver to ground

Not installed

W10

Guard driver +IN

Selects the single-shield guard driver

Not installed

W11

Reference input

Connects the reference of the in-amp to the offset-adjustable voltage reference

Not installed

W12

Reference input

Connects the reference of the in-amp to ground

Installed

W13

Reference input

Connects the reference of the in-amp to an external reference supply

Not installed

W14

W15

Guard driver –IN

Connects the negative shield guard driver to ground

Not installed

Table 3. Input/Output

I/O

Function

Positive and negative rails of the in-amp.

GND

Ground for the board. GND1, GND2, GND3, and GND4 designate pins.

+IN/–IN

Positive and negative input of the in-amp.

+GUARD/–GUARD

Positive and negative terminals for use with a shielded cable.

EXT_REF

External reference input for the in-amp.

OUTPUT

Output of the in-amp.

Auxiliary power rails for guard drivers and offset reference circuitry.

Table 4. User-Supplied Parts for Guard and Offset Circuits

Reference Designation

Part

Guard Drivers

C5, C6

0.1 μF, 25 V ceramic capacitor

A2

AD708JN dual precision op amp

Offset Regulators

C7 to C10

0.1 μF, 25 V ceramic capacitor

A1

OP177 precision op amp

CS1, CS2

J500 240 μA current source

R9, R10

5.9 kΩ, 1% metal film resistor