AD594/AD595 is a complete instrumentation amplifier and thermocouple cold junction compensator on a monolithic chip. It combines an ice point reference with a precalibrated amplifier to produce a high level (10 mV/°C) output directly from a ther- mocouple signal. Pin-strapping options allow it to be used as a linear amplifier-compensator or as a switched output setpoint controller using either fixed or remote setpoint control. It can be used to amplify its compensation voltage directly, thereby converting it to a stand-alone Celsius transducer with a low impedance voltage output. The AD594/AD595 includes a thermocouple failure alarm that indicates if one or both thermocouple leads become open. The alarm output has a flexible f
The AD594 and AD595 are monolithic thermocouple amplifiers that integrate cold‑junction compensation, amplification, and a low‑impedance voltage output in a single IC package. They are precalibrated for Type J (AD594) or Type K (AD595) thermocouples and can also be used with other thermocouple types via pin‑strapping and external calibration.
Key features include a 10 mV/°C output, wide supply range (+5 V to +15 V single‑supply, up to +30 V dual‑supply), low quiescent current (<1 µA), thermocouple failure alarm, and selectable performance grades (C and A versions). The document provides functional block diagrams, connection examples, and detailed recalibration procedures for adapting the devices to different thermocouple types.
| Supply Voltage Range | +5 V to +15 V (single‑supply), up to +30 V (dual‑supply) |
|---|---|
| Output Scaling | 10 mV/°C |
| Calibration Error at +25 °C | +1 °C (C version) / +3 °C (A version) |
| Closed Loop Gain | 193.4 (AD594) / 247.3 (AD595) |
| Differential Input Range | -10 mV to +50 mV |
The device provides a low‑impedance voltage output of 10 mV per degree Celsius.
It can run from a single supply of +5 V to +15 V, and with a dual supply it can accept voltages up to +30 V.