THMC50

REMOTE/LOCAL TEMPERATURE MONITOR AND

FAN CONTROLLER WITH SMBus INTERFACE

SLIS090 – JULY 1999

1

POST OFFICE BOX 655303

Control

Functions

Hardware Trip Point

1

2

3

4

5

6

7

8

16

15

14

13

12

11

10

9

FAN_OFF

MR

AUXRST

GND

VCC3AUX

VCC3

RST

FAN_SPD/NTEST_IN

SDA

SCL

INT

ADD/NTEST_OUT

GPI

THERM

REMOTE_DIODE+

REMOTE_DIODE–

16-Pin SSOP DBQ Package

(TOP VIEW)

NOTE: Pin assignments are preliminary.

description

The THMC50 is a local/remote temperature monitor with two voltage supervisor circuits and an 8-bit, 0-V to

2.5-V DAC designed for temperature monitoring and fan control via a two-wire SMBus serial interface. The

THMC50 is intended for use in personal computer applications according to the Advanced Configuration and

Power Interface (ACPI) thermal model. The device is also suitable for use in network routers and hubs, office

equipment, telephone switching networks, industrial control applications, and any other application requiring

temperature monitoring, fan speed control, and two 3.3-V supply voltage supervisors.

Temperature data is reported in a 2s complement, 8-bit binary format. The local temperature sensor can be used

™ microprocessors, can be used to monitor the actual CPU die

temperature. For applications not using a microprocessor with an integrated thermal diode, an inexpensive

diode-connected 2N3904 NPN transistor can also be used to sense the remote temperature.

The THMC50 provides maskable interrupts for under/over temperature condition with default or user adjustable

limit values. If the temperature limit values are exceeded, the THMC50 asserts INT low. If the default thermal

limits are exceeded, the THERM terminal is asserted low, and the FAN_SPD analog output automatically goes

to full-scale voltage to set the fan at maximum speed. THERM can also be used as an input to instantly command

full fan speed.

The 8-bit, 0–2.5 V DAC output of the THMC50, along with an external amplifier circuit, provides the means to

control the speed of a cooling fan. Fault tolerant fan-speed control is achieved through default and

user-programmable values for high temperature limits that command the fan to full speed once the temperature

limits are exceeded.

functions are assured down to 1-V supply voltage.

Copyright

© 1999, Texas Instruments Incorporated

PRODUCTION DATA information is current as of publication date.

Products conform to specifications per the terms of Texas Instruments

standard warranty. Production processing does not necessarily include

testing of all parameters.

Please be aware that an important notice concerning availability, standard warranty, and use in critical applications of

Texas Instruments semiconductor products and disclaimers thereto appears at the end of this data sheet.

Intel and Pentium are registered trademarks of Intel Corporation.

Sun is a registered trademark and UltraSPARC is a trademark of Sun Microsystems.