7 Detailed Description

7.1 Overview

The TMP300 is a thermal sensor designed for overtemperature protection circuits in electronic systems. The

TMP300 uses a set resistor to program the trip temperature of the digital output. An additional high-impedance

(210 kΩ) analog voltage output provides the temperature reading.

7.2 Feature Description

7.2.1 Calculating RSET

The set resistor (RSET) provides a threshold voltage for the comparator input. The TMP300 trips when the VTEMP

pin exceeds the TSET voltage. The value of the set resistor is determined by the analog output function and the

3-μA internal bias current.

To set the TMP300 to trip at a preset value, calculate the RSET resistor value according to Equation 1 or

Equation 2:

R

=

SET

(T

0.01+0.5)

´

SET

3e-

6

(1)

where

• TSET is in °C; or

R

ink

=

W

SET

10(50+T

)

SET

3

(2)

where

• TSET is in °C.

7.2.2 Using VTEMP to Trip the Digital Output

The analog voltage output can also serve as a voltage input that forces a trip of the digital output to simulate

a thermal event. This simulation facilitates easy system design and test of thermal safety circuits, as shown in

Figure 7-1.

R

INT

210kW

R

SET

T

SET

OUT

V+

HYST

SET

V

TEMP

TMP300

3 A

m

Proportional

toT

A

Open-DrainControl

Voltagesource

totesttrippoint.

Figure 7-1. Applying Voltage to Trip Digital Output

TMP300

SBOS335F – JUNE 2005 – REVISED JANUARY 2023

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