Accurate Remote Diode Digital Temperature Sensor w/ Integrated Fan Control - LM63


Accurate Remote Diode Digital Temperature Sensor w/ Integrated Fan Control



The LM63 is a remote diode temperature sensor with integrated fan control. The LM63 accurately measures: (1) its own temperature and (2) the temperature of a diode-connected transistor, such as a 2N3904, or a thermal diode commonly found on Computer Processors, Graphics Processor Units (GPU) and other ASIC's. The LM63 remote temperature sensor's accuracy is factory trimmed for the series resistance and 1.0021 non-ideality of the Intel 0.13 µm Pentium 4 and Mobile Pentium 4 Processor-M thermal diode. The LM63 has an offset register to correct for errors caused by different non-ideality factors of other thermal diodes.

The LM63 also features an integrated, pulse-width-modulated (PWM), open-drain fan control output. Fan speed is a combination of the remote temperature reading, the lookup table and the register settings. The 8-step Lookup Table enables the user to program a non-linear fan speed vs. temperature transfer function often used to quiet acoustic fan noise.


  • Accurately Senses Diode-Connected 2N3904 Transistors or Thermal Diodes On Board Large Processors or ASICs
  • Accurately Senses its Own Temperature
  • Factory Trimmed for Intel Pentium 4 and Mobile Pentium 4 Processor-M Thermal Diodes
  • Integrated PWM Fan Speed Control Output
  • Acoustic Fan Noise Reduction With User-Programmable 8-Step Lookup Table
  • Multi-Function, User-Selectable Pin for Either ALERT Output, or Tachometer Input, Functions
  • Tachometer Input for Measuring Fan RPM
  • Smart-Tach Modes for Measuring RPM of Fans With Pulse-Width-Modulated Power as Shown in Typical Application
  • Offset Register can Adjust for a Variety of Thermal Diodes
  • 10 Bit Plus Sign Remote Diode Temperature Data Format, With 0.125°C Resolution
  • SMBus 2.0 Compatible Interface, Supports TIMEOUT
  • LM86-Compatible Pinout
  • LM86-Compatible Register Set
  • 8-Pin SOIC Package

Intel is a trademark of Texas Instruments. Pentium is a trademark of Texas Instruments. All trademarks are the property of their respective owners.

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Parametrics Compare all products in Monitoring & Fan Control

Analog Inputs
No. of Temperature Sensors
Operating Temperature Range (C)
Temperature Sensor Accuracy (C)
Temperature Sensor Resolution (C)
PWM Duty Cycle Resolution (bits)
Fan Speed Measurement Accuracy (%)
Interface Type
Fan Control Method
Fan Control Output(s)
TruTherm(TM) Beta Compensation
VID Inputs
Fan Speed Inputs
Interrupt Outputs (Count)
Quiescent Current (mA)
LM63 LM96163
0    0   
2    2   
8SOIC    10WSON   
0 to 125    -40 to 125   
1C max for 60C to 100C
3C max for 25C to 125C   
0.75C max for 50 to 105
1.5C max for 40 to 125
3C max for 25C to 125C   
0.125    0.125   
6    8   
10    7   
Catalog    Catalog   
SMBus    SMBus   
Lookup Table    Lookup Table 12 point   
1 PWM    1 PWM   
No    Yes   
0    0   
1    1   
1    2   
1.3    0.456