Features: Two-Wire SMBus Serial Interface
3.3 V Operation
Low Operating and Standby Current
Remote and Local Temperature Monitoring
0 V to 2.5 V, 8-bit DAC for Fan Speed Control
Two Voltage Supervisors With Reset Functions
Fault Tolerant Fan Control With Automatic Hardware Trip Point
Bidirectional Thermal Overload Indicator
ACPI Thermal Model Compliant
Specifications
| Voltage on VCC3AUX supply terminal, V(VCC3AUX) . . . . . . . . . . . . . . . . . . . . 0.3 V to 5.75 V |
| Maximum voltage allowed for FAN_OFF pullup, V(FAN_OFF) . . . . . . . . . . .. . . . . . 5.5 V |
| Input voltage on any I/O terminals (except analog inputs), V(IOIN) . . . . 0.3 V to V(VCC3AUX +0.3 V |
| Input current on any I/O terminal (see Note 2), I(IOIN) . . . . . . . . . .. . . . . . .5 mA to 5 mA |
| Package input current (see Note 2), I(PACKAGE) . . . . . . . . . . . . . . . . . . . .20 mA to 20 mA |
| Input voltage on REMOTE_DIODE terminal,V(REMOTE_DIODE) . . . . . . . . . . . . ..0.3 V to 0.8 V |
| REMOTE_DIODE input current, I(REMOTE_DIODE) . . . . . . . . . . . . . . . . . . . .1 mA to 1 mA |
| Human body model ESD susceptibility, V(HBMESD) . . . . . . . . . . . . . . . . . . . . . . . . .±2 kV |
| Continuous power dissipation (see Note 3), PD. . . . . . . . . . . . . . . . . . . . . . 330 mW |
| Operating case temperature range, TC . . . . . . . . . . . . . . . .. . . . .40°C to 125°C |
| Storage temperature (see Note 4), Tstg . . . . . . . . . . . . . . . . . . . . . . .65°C to 165°C |
| Junction temperature, TJ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .150°C |
| Lead temperature (soldering, 10 sec), T(LEAD) . . . . . . . . . . . . . . . . . . . . .300°C |
DescriptionThe 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 THMC50 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 of THMC50 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) UltraSPARCE microprocessors, THMC50 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 THMC50 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, 02.5 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.
THMC50 Data Sheet
