1FEATURES

23• 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 nonALERT

Output, or Tachometer Input,

Functions width•

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

APPLICATIONS

• Computer Processor Thermal Management

(Laptop, Desktop, Workstations, Servers)

• Graphics Processor Thermal Management

• Electronic Test Equipment

• Projectors

• Office Equipment

• Industrial Controls

DESCRIPTION

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 nonALERT

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.