AD637JRZ-R7 datasheet(21/25 Pages) AD

21 / 25 page

Data Sheet

AD637

Rev. L | Page 21 of 25

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

RMS_IN is capacitively coupled to Pin 15 (VIN of SOIC package)

of 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

Sallen-Key filter whose fC < 0.5 Hz. Users can connect to

the 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

AD637JRZ-R7 数据表(PDF) 21 Page - Analog Devices