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TEMPERATURE MONITORING

POWER DISSIPATION

NOISE PERFORMANCE

DNC

TEMP

V

OUT

V

IN

GND

DNC

NC

TRIM

REF50xx

V

TEMP

2.6mV/ C

°

NOTE:(1)Lowdriftopamp,suchastheOPA333,OPA335,orOPA376.

+V

REF5020,, REF5025

REF5030, REF5040

REF5045, REF5050

SBOS410 – JUNE 2007

The temperature output terminal (TEMP, pin 3)

The REF50xx family is specified to deliver current

provides a temperature-dependent voltage output

loads of ±10mA over the specified input voltage

with approximately 60k

Ω source impedance. As seen

range. The temperature of the device increases

in Figure 8, the output voltage follows the nominal

according to the equation:

relationship:

Where:

This pin indicates general chip temperature, accurate

to approximately ±15

°C. Although it is not generally

suitable for accurate temperature measurements, it

can be used to indicate temperature changes or for

temperature compensation of analog circuitry. A

(

°C/W)

temperature change of 30

°C corresponds to an

approximate 79mV change in voltage at the TEMP

The REF50xx junction temperature must not exceed

pin.

the absolute maximum rating of +150

°C.

The TEMP pin has high output impedance (see

Figure 21). Loading this pin with a low-impedance

circuit induces a measurement error; however, it does

Typical 0.1Hz to 10Hz voltage noise for each member

of the REF50xx family is specified in the Electrical

errors caused by low-impedance loading, buffer the

Characteristics: Per Device table. The noise voltage

TEMP pin output with a suitable low-temperature drift

increases

with

output

voltage

and

operating

op amp, such as the OPA333, OPA335, or OPA376,

temperature. Additional filtering can be used to

as shown in Figure 24.

improve output noise levels, although care should be

taken to ensure the output impedance does not

degrade performance.

Figure 24. Buffering the TEMP Pin Output

10

Copyright © 2007, Texas Instruments Incorporated

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