TMP12

REV. 0

–4–

ABSOLUTE MAXIMUM RATINGS*

Supply Voltage . . . . . . . . . . . . . . . . . . . . . . . .

0.3 V to

15 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

Dice Junction Temperature . . . . . . . . . . . . . . . . . . . . .

175

°C

Storage Temperature Range . . . . . . . . . . . .

65

°C to 160°C

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

300

°C

Package Type

Θ

JA

Θ

JC

Units

8-Pin Plastic DIP (P)

43

°C/W

8-Lead SOIC (S)

43

°C/W

NOTES

1

ΘJA is specified for device in socket (worst case conditions).

2

ΘJA is specified for device mounted on PCB.

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

specification is not implied. Exposure to the above maximum

rating conditions for extended periods may affect device reli-

ability.

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 packaging

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

1

Description

Option

TMP12FP

XIND

Plastic DIP

N-8

TMP12FS

XIND

SOIC

SO-8

TMP12GBC

25

°C

Die

NOTE

40

°C to 125°C

FUNCTIONAL DESCRIPTION

The TMP12 incorporates a heating element, temperature sen-

sor, 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 bandgap

voltage reference which provides both a constant 2.5 V output

and a voltage which 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:

PD =

V2

R

52 V

100

Ω

= 0.25 W ,

=

which generates a temperature rise of about 32

°C in still air for

the SO packaged device. With an airflow of 450 feet per minute

(FPM), the temperature rise is about 22

°C. By selecting a temp-

erature 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 conjunc-

tion 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 re-

lays directly. Operating from a single

5 V supply, the quiescent

current is only 600

µA (max), without the heater resistor current.