LM41

LM41 Hardware Monitor with Thermal Diode Inputs and SensorPath™ Bus May 2004 LM41 Hardware Monitor with Thermal Diode Inputs and SensorPath™ Bus General Description The LM41 is a hardware monitor that measures 2 temperature zones, 5 voltages and has a single-wire interface compatible with National Semiconductor’s SensorPath bus. SensorPath data is pulse width encoded, thereby allowing the LM41 to be easily connected to many general purpose micro-controllers. Several National Semiconductor Super I/O products include a fully integrated SensorPath master, that when connected to the LM41 can realize a hardware monitor function that includes limit checking for measured values, autonomous fan speed control and many other functions. The LM41 measures the temperature of its own die as well as one external device such as a processor thermal diode or a diode connected transistor. The LM41 can resolve temperatures up to 255˚C and down to -256˚C. The operating temperature range of the LM41 is 0˚C to +125˚C. Using Σ∆ ADC it measures +1.2V, +2.5V, +3.3V, +5V and +12V analog input voltages with internal scaling resistors. The address programming pin allows two LM41’s to be placed on one SensorPath bus. — Internal scaling resistors for all inputs — Monitors +1.2V, +2.5 V, +3.3 V, +5 V and +12 V n Temperature Sensing — Remote diode temperature sensor zone — Internal local temperature zone — 0.5 ˚C resolution — Measures temperatures up to 140 ˚C n 14-lead TSSOP package Key Specifications n ...