The LM40 is a hardware monitor that measures 3 temperature zones, 5 voltages and has a single-wire interface compatible with National Semiconductor’s SensorPath bus.
The LM40 is a hardware monitor that measures up to three temperature zones and five analog voltages. It communicates over National Semiconductor's single‑wire SensorPath™ bus, allowing easy integration with micro‑controllers and Super I/O devices.
The device includes two programmable hardware addresses, internal scaling resistors for voltage inputs, and dual remote diode temperature sensor zones. It is intended for use in micro‑processor based equipment, power supplies, and other applications requiring precise temperature and voltage monitoring.
| Voltage Measurement Accuracy | +2 % (max) |
|---|---|
| Temperature Sensor Accuracy | +3 °C (max) |
| LM40 Junction Temperature Range | 0 °C to +85 °C |
| Remote Temperature Accuracy Range | 0 °C to +100 °C |
| Power Supply Voltage | +3.0 V to +3.6 V |
| Average Power Supply Current | 0.5 mA (typ) |
| Conversion Time (all Channels) | 29.6 ms to 1456 ms |
| Temperature Resolution | 0.5 °C |
| Hardware Programmable Addresses | 2 |
| Monitored Voltages | +1.2V, +2.5V, +3.3V, +5V, +12V |
The LM40 operates from 0 °C to +125 °C.
It supports two hardware programmable addresses.
It monitors +1.2 V, +2.5 V, +3.3 V, +5 V and +12 V.
The device provides a temperature resolution of 0.5 °C.