LM40 Hardware Monitor with Dual Thermal Diodes and SensorPath™ Bus
The National Semiconductor LM40 is a hardware monitor designed to measure three temperature zones and five voltage levels using a single-wire SensorPath bus interface. It features an internal local temperature sensor and two remote diode temperature sensor zones for monitoring processors or other devices. The device includes a 9-bit A/D converter with internal scaling resistors to monitor +1.2V, +2.5V, +3.3V, +5V, and +12V analog inputs.
| Voltage Measurement Accuracy | +2 % (max) |
|---|---|
| Temperature Sensor Accuracy | +3 °C (max) |
| Operating Temperature Range | 0°C to +125°C |
| Power Supply Voltage | +3.0 V to +3.6 V |
| Average Power Supply Current | 0.5 mA (typ) |
The device measures +1.2V, +2.5V, +3.3V, +5V and +12V analog input voltages with internal scaling resistors.
It measures three temperature zones: its own die as well as two external devices.
The device has a 0.5 °C resolution for its temperature sensing capabilities.