PRODUCT DESCRIPTION

The AD693 is a monolithic signal conditioning circuit which accepts low-level inputs from a variety of transducers to control a standard 4–20 mA, two-wire current loop. An on-chip voltage reference and auxiliary amplifier are provided for transducer excitation; up to 3.5 mA of excitation current is available when the device is operated in the loop-powered mode. Alternatively, the device may be locally powered for three-wire applications when 0–20 mA operation is desired.

FEATURES

Instrumentation Amplifier Front End

Loop-Powered Operation

Precalibrated 30 mV or 60 mV Input Spans

Independently Adjustable Output Span and Zero

Precalibrated Output Spans: 4–20 mA Unipolar

0–20 mA Unipolar

12 ± 8 mA Bipolar

Precalibrated 100 Ω RTD Interface

6.2 V Reference with Up to 3.5 mA of Current Available

Uncommitted Auxiliary Amp for Extra Flexibility

Optional External Pass Transistor to Reduce

Self-Heating Errors