AD637

Rev. K | Page 16 of 20

EVALUATION BOARD

Figure 23 shows a digital image of the AD637-EVALZ, an

evaluation board specially designed for the AD637. It is

available at www.analog.com and is fully tested and ready for

bench testing after connecting power and signal I/O. The circuit

is configured for dual power supplies, and standard BNC

connectors serve as the signal input and output ports.

Referring to the schematic in Figure 30, the input connector

the AD637. The DC_OUT connector is connected to Pin 11,

RMS OUT, with provisions for connections to the output buffer

between Pin 1 and Pin 16. The buffer is an uncommitted op

amp, and is configured on the AD637-EVALZ as a low-pass

buffer by moving the FILTER switch to the on position.

DC_OUT is still the output of the AD637, and the test loop,

BUF_OUT, is the output of the buffer. The R2 trimmer adjusts

the output offset voltage.

The LPF frequency is changed by changing the component

values of CF1, CF2, R4, and R5. See Figure 24 and Figure 30 to

locate these components. Note that a wide range of capacitor

and resistor values can be used with the AD637 buffer amplifier.

Figure 23. AD637-EVALZ