Part # LM85 datasheet

Part Manufacturer: National Semiconductor

National Semiconductor

Part Description: LM85 Hardware Monitor with Integrated Fan Control

Part Details:

LM85 March 2003 Hardware LM85Hardware Monitor with Integrated Fan ControlGeneral Description n Noise filtering of temperature reading for fan control Monitor n 1.0°C digital temperature sensor resolution The LM85, hardware monitor, has a two wire digital interface n 3 PWM fan speed control outputs compatible with SMBus 2.0. Using an 8-bit ADC, theLM85 measures: n 4 fan tachometer inputs n Monitors 5 VID control lines ­ the temperature of two remote diode connected transis- tors as well as its own die n 24-pin QSOP package with n XOR-tree test mode ­ the V , 2.5V, 3.3VSBY, 5.0V, and 12V supplies (inter- CCP nal scaling resistors). Key Specifications To set fan speed, the LM85 has three PWM outputs that are Integrated each controlled by one of three temperature zones. The n Voltage Measurement Accuracy ±2% FS (max) LM85 includes a digital filter that can be invoked to smooth n Resolution 8-bits, 1°C temperature readings for better control of fan speed. The n Temperature Sensor Accuracy ±3°C (max) LM85 has four tachometer inputs to measure fan speed. n Temperature Range Limit and status registers for all measured values are in- -- LM85 Operational 0°C to +85°C cluded. -- Remote Temp Accuracy 0°C to +125°C n Power Supply Voltage +3.0V to +3.6V Features Fan n Power Supply Current 0.53 mA n 2-wire, SMBus 2.0 compliant, serial digital interface n 8-bit ADC Applications Control n Monitors V , 2.5V, 3.3 VSBY, 5.0V, and 12V CCP n Desktop PC

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LM85.pdf Datasheet