AD594/AD595 is a monolithic integrated temperature sensor with low power consumption, high accuracy and high output signal-to-noise ratio. It can directly convert thermocouple signals to 10 mV/°C output and has temperature compensation function. AD594/AD595 can be used as a linear amplifier-compensator or as a fixed or remote setpoint control switched output setpoint controller. It can also be used to amplify its compensation voltage directly, thereby converting it to an independent Celsius temperature sensor with a low output impedance voltage output. AD594/AD595 also includes a thermocouple failure alarm that indicates if one or both thermocouple leads are open. The alarm output has flexible formats, including TTL drive and CMOS drive.
The AD594 (type J) and AD595 (type K) are laser‑trimmed, monolithic thermocouple amplifiers that provide cold‑junction compensation, amplification, and a low‑impedance voltage output of 10 mV per degree Celsius. They can be configured as set‑point controllers or stand‑alone Celsius transducers and include a thermocouple failure alarm with TTL capability.
Both devices operate from a single supply of +5 V to +15 V (or up to +30 V with a dual‑supply configuration) and draw very low quiescent current (<1 mW). Pin‑strapping allows use with type J, K, or T thermocouples, and the differential input rejects common‑mode noise. Detailed specifications, functional block diagrams, and calibration procedures are provided for precise temperature measurement.
| Output Transfer Function | 10 mV/°C |
|---|---|
| Supply Voltage Range | +5 V to +15 V (single) / +5 V to +30 V (dual) |
| Calibration Error at +25 °C | +3 °C (AD594) / +1 °C (AD595) |
| Operating Temperature Range (measurement) | 0 °C to +50 °C |
| Closed‑Loop Gain | 193.4 (AD594) / 247.3 (AD595) |
The device provides a low‑impedance output of 10 mV for each degree Celsius of temperature change.
They can be powered from a single supply of +5 V to +15 V, or from a dual supply up to +30 V for extended temperature ranges.
AD594 is pre‑trimmed for type J, AD595 for type K, and both can be used with type T thermocouples.