**AD590JRZ: A Comprehensive Guide to the Precision Monolithic Temperature Sensor**

The **AD590JRZ** is a classic two-terminal integrated circuit temperature transducer from Analog Devices that has stood the test of time. It produces an output current that is **linearly proportional to absolute temperature** (in Kelvin), a feature that simplifies many temperature measurement challenges. Housed in a TO-92 package, this sensor is renowned for its **exceptional ease of use and high accuracy**.

**Operating Principle and Key Features**

The fundamental principle of the AD590JRZ is its behavior as a high-impedance, constant current regulator. The device is designed to provide an output current of **1 µA per Kelvin** of the sensed temperature. This means that at 25°C (which is 298.15K), the sensor will output approximately 298.2 µA.

This current-output nature offers significant advantages. It is inherently immune to noise pick-up and voltage drops across long wires, making it ideal for remote sensing applications. The AD590JRZ requires a supply voltage from **+4V to +30V**, and its output current is solely a function of temperature, not the supply voltage, as long as the supply remains within this specified range.

The "JRZ" suffix denotes a specific grade with a calibrated accuracy of **±0.5°C at +25°C** and a linearity error of ±0.3°C over the full rated temperature range of -55°C to +150°C. This level of precision makes it suitable for a wide array of demanding applications.

**Typical Applications and Circuit Configurations**

The most basic circuit requires only a single resistor. By passing the output current through a precision resistor (e.g., 1 kΩ), a voltage output of **1 mV/K** is generated, which can be easily measured by an analog-to-digital converter (ADC) or a voltmeter.

Its applications are vast and include:

* **Digital Thermometry:** Easily interfaced with microcontrollers using an ADC.

* **Temperature Compensation:** For correcting drift in other components or systems.

* **Industrial Process Control:** Its ruggedness and remote sensing capability are key benefits.

* **HVAC Systems:** Monitoring and controlling ambient temperature.

* **Battery Management Systems (BMS):** Monitoring battery temperature for safety and performance.

**Advantages and Considerations**

The primary advantages of the AD590JRZ are its **linear output, wide operating range, and inherent noise immunity**. Its two-terminal construction makes it incredibly easy to implement, almost like a passive component.

However, designers must consider a few points. Being an analog sensor, it requires an ADC for digital systems. For measurements in Celsius or Fahrenheit, a subtraction circuit is needed to offset the 273.2 µA output corresponding to 0°C (273.2K). Furthermore, self-heating is minimal but should be considered in ultra-low power or precision applications.

ICGOODFIND: The **AD590JRZ** remains a highly reliable and straightforward solution for accurate temperature measurement across a broad spectrum of industries. Its **current-output principle, excellent linearity, and robust design** ensure its continued relevance in both new designs and legacy systems, offering a perfect blend of performance and simplicity.

**Keywords:**

Temperature Sensor

Current Output

Absolute Temperature

Linear IC

Precision Measurement