THMC50_08 Datasheet, PDF (1/34 Pages) Texas Instruments – REMOTE/LOCAL TEMPERATURE MONITOR AND FAN CONTROLLER WITH SMBus INTERFACE

THMC50
REMOTE/LOCAL TEMPERATURE MONITOR AND
FAN CONTROLLER WITH SMBus INTERFACE
SLIS090 – JULY 1999
D Two-Wire SMBus Serial Interface
D 3.3 V Operation
D Low Operating and Standby Current
D Remote and Local Temperature Monitoring
D 0 V to 2.5 V, 8-bit DAC for Fan Speed
Control
D Two Voltage Supervisors With Reset
Functions
D Fault Tolerant Fan Control With Automatic
Hardware Trip Point
D Bidirectional Thermal Overload Indicator
D ACPI Thermal Model Compliant
16-Pin SSOP DBQ Package
(TOP VIEW)
FAN_OFF
1
MR
2
AUXRST
3
GND
4
VCC3AUX
5
VCC3
6
RST
7
FAN_SPD/NTEST_IN
8
16
SDA
15
SCL
14
INT
13
ADD/NTEST_OUT
12
GPI
11
THERM
10
REMOTE_DIODE+
9
REMOTE_DIODE–
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
to monitor the ambient temperature, while a remote thermal diode, such as the one present on the Intel^®
Pentium^® II, III, and the Sun^® UltraSPARC™ 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.
The THMC50 also provides two reset functions for the V_(VCC3AUX) and V_(VCC3) supply voltage. The reset
functions are assured down to 1-V supply voltage.
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.
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.
• POST OFFICE BOX 655303 DALLAS, TEXAS 75265
Copyright © 1999, Texas Instruments Incorporated
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