DNC

TEMP

V

OUT

V

IN

GND

DNC

NC

TRIM/NR

REF50xx

1 F

m

+V

SUPPLY

TEMPERATURE DRIFT

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

(1)

POWER DISSIPATION

TEMPERATURE MONITORING

NOISE PERFORMANCE

REF5010

,, REF5020

REF5025, REF5030

REF5040, REF5045, REF5050

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

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 25.

Figure 24. Noise Reduction Using the TRIM/NR

Pin

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 25. Buffering the TEMP Pin Output

The REF50xx features a maximum drift coefficient of

The REF50xx family is specified to deliver current

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

loads of ±10mA over the specified input voltage

the standard-grade.

range. The temperature of the device increases

according to the equation:

Where:

The temperature output terminal (TEMP, pin 3)

provides a temperature-dependent voltage output

with approximately 60k

Ω source impedance. As seen

in Figure 8, the output voltage follows the nominal

θ

JA

= Junction-to-ambient thermal resistance

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

can be used to indicate temperature changes or for

Typical 0.1Hz to 10Hz voltage noise for each member

temperature compensation of analog circuitry. A

of the REF50xx family is specified in the Electrical

temperature change of 30°C corresponds to an

Characteristics: Per Device table. The noise voltage

approximate 79mV change in voltage at the TEMP

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.

10

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