AD693芯片资料.pdfVIP

Loop-Powered 4–20 mA Sensor Transmitter AD693 FEATURES FUNCTIONAL BLOCK DIAGRAM 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 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 PRODUCT DESCRIPTION PRODUCT HIGHLIGHTS The AD693 is a monolithic signal conditioning circuit which 1. The AD693 is a complete monolithic low-level voltage-to- accepts low-level inputs from a variety of transducers to control a current loop signal conditioner. standard 4–20 mA, two-wire current loop. An on-chip voltage 2. Precalibrated output zero and span options include reference and auxiliary amplifier are provided for transducer 4–20 mA, 0–20 mA, and 12 ± 8 mA in two- and three-wire excitation; up to 3.5 mA of excitation current is available when the configurations. device is operated in the loop-powered mode. Alternatively, the device may be locally powered for three-wire applications when 3. Simple resistor programming adds a continuum of ranges 0–20 mA operation is