REV. B

TMP12

–3–

CAUTION

ESD (electrostatic discharge) sensitive device. Electrostatic charges as high as 4000 V readily

accumulate on the human body and test equipment and can discharge without detection. Although

the TMP12 features proprietary ESD protection circuitry, permanent damage may occur on

devices subjected to high-energy electrostatic discharges. Therefore, proper ESD precautions are

recommended to avoid performance degradation or loss of functionality.

WARNING!

ESD SENSITIVE DEVICE

ABSOLUTE MAXIMUM RATINGS

*

Supply Voltage . . . . . . . . . . . . . . . . . . . . . . . . –0.3 V to +11 V

Heater Voltage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 V

Setpoint Input Voltage . . . . . . . . . . . –0.3 V to [(V+) + 0.3 V]

Reference Output Current . . . . . . . . . . . . . . . . . . . . . . . 2 mA

Open-Collector Output Current . . . . . . . . . . . . . . . . . 50 mA

Open-Collector Output Voltage . . . . . . . . . . . . . . . . . . . . 15 V

Operating Temperature Range . . . . . . . . . . –55

°C to +150°C

Storage Temperature Range . . . . . . . . . . . . –65

°C to +160°C

Lead Temperature (Soldering, 60 sec) . . . . . . . . . . . . 300

°C

Package Type

JA

JC

Unit

8-Lead SOIC (S)

158

1

43

2

°C/W

NOTES

1

2

*CAUTION

1. Stresses above those listed under Absolute Maximum Ratings

may cause permanent damage to the device. This is a stress

rating only and functional operation at or above this specifi-

cation is not implied. Exposure to the above maximum rating

conditions for extended periods may affect device reliability.

2. Digital inputs and outputs are protected; however, permanent

damage may occur on unprotected units from high-energy

electrostatic fields. Keep units in conductive foam or packag-

ing at all times until ready to use. Use proper antistatic handling

procedures.

3. Remove power before inserting or removing units from their

sockets.

ORDERING GUIDE

Temperature

Package

Package

Model/Grade

Range

Description Option

TMP12FS

–40

°C to +85°C

SOIC

R-8

TMP12FS-REEL

–40

°C to +125°C SOIC

R-8

FUNCTIONAL DESCRIPTION

The TMP12 incorporates a heating element, temperature sensor,

and two user-selectable setpoint comparators on a single substrate.

By generating a known amount of heat, and using the setpoint

comparators to monitor the resulting temperature rise, the TMP12

can indirectly monitor the performance of a system’s cooling fan.

The TMP12 temperature sensor section consists of a band gap

voltage reference that provides both a constant 2.5 V output and

a voltage that is proportional to absolute temperature (VPTAT).

The VPTAT has a precise temperature coefficient of 5 mV/K

and is 1.49 V (nominal) at 25

°C. The comparators compare

VPTAT with the externally set temperature trip points and

generate an open-collector output signal when one of their

respective thresholds has been exceeded.

The heat source for the TMP12 is an on-chip 100

Ω low tempco

thin-film resistor. When connected to a 5 V source, this resistor

dissipates

P

V

R

V

W

=

2

2

5

100

025

Ω

.

which generates a temperature rise of about 32

°C in still air

for the SOIC packaged device. With an airflow of 450 feet

per minute (FPM), the temperature rise is about 22

°C. By

selecting a temperature setpoint between these two values,

the TMP12 can provide a logic-level indication of problems

in the cooling system.

A proprietary, low tempco thin-film resistor process, in conjunction

with production laser trimming, enables the TMP12 to provide a

temperature accuracy of

±3°C (typ) over the rated temperature

range. The open-collector outputs are capable of sinking 20 mA,

allowing the TMP12 to drive small control relays directly. Oper-

ating from a single 5 V supply, the quiescent current is only

600

µA (max), without the heater resistor current.