AD694 is a 4-20mA current sensor from Analog Devices. This sensor is an integrated circuit design that can accept high-level signal inputs and convert them to standard 4-20mA current loop outputs to control valves, actuators and other devices commonly used in process control. The input signal is buffered by an input amplifier that can be used to scale the input signal or buffer the output from a current mode DAC. Pre-calibrated input ranges of 0 V to 2 V and 0 V to 10 V are selected by simple pin strapping; other ranges can be programmed with external resistors. The output stage compliance extends to within 2 V of VS and its special design allows the output voltage to extend below common in dual supply operation. An alarm warns of an open 4-20 mA current loop.
The AD694 is a monolithic current transmitter that converts high‑level voltage inputs to a standard 4‑20 mA loop for controlling valves, actuators and other process‑control devices. It features precalibrated input ranges, programmable voltage reference, and optional external pass transistor to reduce self‑heating.
The document includes functional block diagrams, detailed specifications, pin configuration, wiring recommendations, power‑dissipation calculations and adjustment procedures for offset and span. It also covers dual‑supply operation, non‑resistive load handling, and safety guidelines.