The LM32 is a digital temperature sensor from National Semiconductor that measures 3 temperature zones and has a single-wire interface compatible with National Semiconductor's SensorPath bus. Sensor-Path data is pulse width encoded, thereby allowing the LM32 to be easily connected to many general purpose micro-controllers. Several National Semiconductor Super I/O prod- ucts include a fully integrated SensorPath master, that when connected to an LM32 can realize a hardware monitor func- tion that includes limit checking for measured values, au- tonomous fan speed control and many other functions. The LM32 measures the temperature of its own die as well as two external devices such as a processor thermal diode or a diode connected transistor. The LM32 can resolve tem- peratures up to 255˚C and down to -256˚C. The operating temperature range of the LM32 is 0˚C to +125˚C. The ad- dress programming pin allows two LM32s to be placed on one SensorPath bus.
The LM32 is a digital temperature sensor that measures three zones – its own die and two external thermal diodes – and communicates via National Semiconductor's SensorPath™ single‑wire bus. It offers 0.5 °C resolution, up to 255 °C measurement range, and programmable addresses for multiple devices on the same bus.
The document provides detailed pin descriptions, electrical characteristics, timing diagrams, mechanical dimensions, and application hints for PCB layout and noise mitigation. It also includes safety notices for life‑support use and compliance information.
| Operating Temperature Range | 0 °C to +125 °C |
|---|---|
| Resolution | 0.5 °C |
| Power Supply Voltage | +3.0 V to +3.6 V |
| Average Power Supply Current | 0.5 mA (typ) |
| Temperature Sensor Accuracy | ±3 °C (max) |
| Conversion Time | 22.5 ms to 1456 ms |
| Package | 14‑lead TSSOP |
| Remote Diode Zones | 2 zones |
The LM32 operates from 0 °C up to +125 °C.
It supports two remote diode temperature sensor zones.
The typical average power supply current is 0.5 mA.
The ADD pin is the digital input used for device number selection.