PRE

POST

6

HYST

NOM

V

V

V

10 (ppm)

V

æ

ö

-

=

×

ç

÷

ç

÷

è

ø

Drift

V

OUTMAX

V

OUTMIN

V

OUT

Tem p Range

=

(

–

×

DNC

TEMP

V

OUT

V

IN

GND

DNC

NC

TRIM/NR

REF50xx

V

TEMP

2.6mV/ C

°

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

+V

REF5010, REF5020, REF5025, REF5030

REF5040, REF5045, REF5050

SBOS410G – JUNE 2007 – REVISED NOVEMBER 2015

www.ti.com

Feature Description (continued)

Figure 37. Buffering the TEMP Pin Output

9.3.2 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 show in Equation 2.

(2)

The REF50xx features a maximum drift coefficient of 3 ppm/°C for the high-grade version, and 8 ppm/°C for the

standard-grade.

9.3.3 Thermal Hysteresis

Thermal hysteresis for the REF50xx is defined as the change in output voltage after operating the device at

25°C, cycling the device through the specified temperature range, and returning to 25°C. It can be expressed as

Equation 3:

where

•

•

•

•

range of –40°C to 125°C and returned to 25°C.

(3)

9.3.4 Noise Performance

Typical 0.1-Hz to 10-Hz voltage noise for each member of the REF50xx family is specified in the table. The noise

voltage increases with output voltage and operating temperature. Additional filtering can be used to improve

output noise levels, although take care to ensure the output impedance does not degrade performance.

For additional information about how to minimize noise and maximize performance in mixed-signal applications

such as data converters, refer to the series of Analog Applications Journal articles entitled, How a Voltage

Reference Affects ADC Performance. This three-part series is available for download from the TI website under

three literature numbers: SLYT331, SLYT339, and SLYT355 for Part I, Part II, and Part III, respectively.

16

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