DNC

TEMP

V

OUT

V

IN

GND

DNC

NC

TRIM/NR

REF50xx

1 F

m

+V

SUPPLY

DNC

TEMP

V

OUT

V

IN

GND

DNC

NC

TRIM/NR

REF50xx

V

TEMP

2.6mV/ C

°

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

+V

Drift +

V

OUTMAX

V

OUT

Temp Range

REF5020-EP, REF5025-EP

REF5040-EP, REF5050-EP

www.ti.com

SBOS471A – APRIL 2010 – REVISED JUNE 2010

The TEMP pin has high output impedance (see

Figure 22). Loading this pin with a low-impedance

circuit induces a measurement error; however, it does

errors caused by low-impedance loading, buffer the

TEMP pin output with a suitable low-temperature drift

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

as shown in Figure 26.

Figure 25. Noise Reduction Using the TRIM/NR

Pin

TEMPERATURE DRIFT

The REF50xx is designed for minimal drift error,

which is defined as the change in output voltage over

temperature. The drift is calculated using the box

method, as described by the following equation:

Figure 26. Buffering the TEMP Pin Output

(1)

POWER DISSIPATION

The REF50xx features a maximum drift coefficient of

The REF50xx family is specified to deliver current

3 ppm/°C for the high-grade version, and 8 ppm/°C

loads of ±10 mA over the specified input voltage

for the standard-grade.

range. The temperature of the device increases

according to the equation:

(2)

TEMPERATURE MONITORING

Where:

The temperature output terminal (TEMP, pin 3)

provides a temperature-dependent voltage output

with approximately 60-k

Ω source impedance. As

seen in Figure 8, the output voltage follows the

nominal relationship:

(°C/W)

The REF50xx junction temperature must not exceed

the absolute maximum rating of +150°C.

This pin indicates general chip temperature, accurate

to approximately ±15°C. Although it is not generally

suitable for accurate temperature measurements, it

NOISE PERFORMANCE

can be used to indicate temperature changes or for

Typical 0.1-Hz to 10-Hz voltage noise for each

temperature compensation of analog circuitry. A

member of the REF50xx family is specified in the

temperature change of 30°C corresponds to an

Electrical Characteristics: Per Device table. The noise

approximate 79 mV change in voltage at the TEMP

voltage increases with output voltage and operating

pin.

temperature. Additional filtering can be used to

improve output noise levels, although care should be

taken to ensure the output impedance does not

degrade performance.

Copyright © 2010, Texas Instruments Incorporated

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