LM64 Datasheet | National Semiconductor

Description The LM64 is a remote diode temperature sensor with PWM fan control. The LM64 accurately measures its own temperature and that of a remote diode. The LM64 remote temperature accuracy is factory trimmed for a MMBT3904 diodeconnected transistor with a 16˚C offset for high temperatures. TACTUAL DIODE JUNCTION = TLM64 + 16˚C The LM64 features a PWM, open-drain, fan control output, 5 GPIO (General Purpose Input/Output) and 5 GPD (General Purpose Default) pins. The 8-step Lookup Table allows for a non-linear fan speed vs. temperature transfer function often used to quiet acoustic fan noise. Key Specifications n Remote Diode Temperature Accuracy (includes quantization error) Ambient Temp 30˚C to 50˚C 0˚C to 85˚C Diode Temp 120˚C to 140˚C 25˚C to 140˚C Max Error ± 1.0˚C (max) ± 3.0˚C (max) n Local Temp Accuracy (includes quantization error) Ambient Temp 25˚C to 125˚C n Power Supply Requirements Max Error ± 3.0˚C (max) Features n n n n n n n n n n Accurately senses remote and local diode temperatures Integrated PWM fan speed control output Programmable 8-step Lookup Table for quieting fans ALERT and T_Crit open-drain outputs Tachometer input for measuring fan RPM 10 bit plus sign remote diode temperature data format, with 0.125˚C resolution SMBus 2.0 patible interface, supports TIMEOUT 5 General Purpose Input/Output pins 5 General Purpose Default input pins 24-pin LLP package Supply DC Voltage Supply DC Current 3.0 V to 3.6 V 1.1 m A (typ) Applications n n n n n n puter Processor Thermal Management Graphics Processor Thermal Management Voltage Regulator Modules Electronic Instrumentation Power Supplies Projectors Connection Diagram © 2003 National Semiconductor Corporation DS200655 .national. Pin Descriptions Pin 1 2 3 4 Name GPIO1 GPIO2 GPIO3 PWM Input/Output Digital Input/ Open-Drain Output Digital Input/ Open-Drain Output Digital Input/ Open-Drain Output Open-Drain Digital Output Function and Connection General Purpose Open-Drain...