100kW

OUT

HYST

SET1

HYST

SET0

1.4V to 3.6V

V

S

GND

SOH

Temperature

Sensor

Hysteresis

Logic

Trip Point

Logic

DS

ADC

HYST

SET0

HYST

SET1

SOH

OUT

Time

T =0

L

C

°

T =60

H

C

°

10 C

°

50 C

°

5 C

°

Measured

Temperature

Changeshysteresis

from10

to

C

5 C

°

°

ForcesOUTpinhigh

regardlessoftemperature

TMP303A

TMP303B

SBOS486B – JULY 2009 – REVISED JANUARY 2011

www.ti.com

APPLICATION INFORMATION

The TMP303A temperature trip window resides within

The

TMP303A

and

TMP303B

are

temperature

the range of 0°C to 60°C. The TMP303B temperature

switches used in battery-powered applications that

trip window resides within the range of 0°C to 55°C.

require

accurate

monitoring

of

a

very

specific

When either of these trip thresholds is crossed, the

temperature range of 0°C to +60°C (TMP303A) or

output (OUT) changes state from low to high. OUT

0°C to +55°C (TMP303B). This functionality is

does not return to its original low state until the

accomplished through the preset trip window and two

temperature crosses the hysteresis threshold and

returns within the range of the 0°C to 60°C (or 0°C to

trip window temperature thresholds are configured at

55°C) window.

the factory; for other trip points, contact a TI

representative. Table 1 summarizes the bit setting

As an example, if the TMP303A is configured with a

versus hysteresis temperature window.

10°C

hysteresis

window

(that

is,

Table 1. Bit Setting vs Hysteresis Window

HYSTERESIS

Set Output High (SOH) pin is intended to add test

GND

GND

1°C

functionality to verify the connectivity of the output

GND

2°C

(OUT)

pin

to

the

system

controller

or

other

temperature response system. The SOH pin is

GND

5°C

internally pulled down to ground with a 100k

Ω

10°C

resistor. If the SOH pin is grounded or left floating, it

has no effect on the behavior of the TMP303A. If the

Configuring the TMP303A/B

SOH pin is pulled high, the TMP303A immediately

forces the output high, regardless of temperature. It is

The TMP303A/B contains an active high, push-pull

very important to note that this response occurs even

output stage and does not require a pull-up resistor to

if the temperature falls within the 0°C to 60°C

temperature window. Figure 11 illustrates this design

diagram of the TMP303A/B.

in graphical form.

Figure 10. TMP303A/B Block Diagram

Power-supply bypassing is strongly recommended;

use a 0.1µF capacitor placed as close as possible to

the supply pin.

Figure 11. TMP303A Output Transfer Curves with

Hysteresis Change from 10°C to 5°C and SOH

Functionality

6

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