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