AD694 Просмотр технического описания (PDF) - Analog Devices

Номер в каталоге

Компоненты Описание

производитель

AD694

4–20 mA Transmitter

Analog Devices 

AD694

Figure 15. Low Cost Sensor Transmitter

The circuit shown, will convert a positive differential signal at

VIN to a 4–20 mA current. The circuit has common-mode range

of 3 V to 8 V. The low end of the common-mode range is limited

by the AD708’s ability to pull down on RS. A single supply am-

plifier could be used instead to extend the common-mode range

down to about 1.5 V.

As shown, the circuit handles positive differential signals (VIN

positive). To handle bipolar differential signals (VIN is positive

or negative), the reference pin of the in amp (Point C) must be

offset positively from the 2 V reference. For example, discon-

necting Point C from the 2 V reference and connecting it to a

3 V source would result in a VA of 1 V (or half scale) for a zero

volt differential input from the sensor.

–12–

REV. B

Share Link: