400ms/div

6

OUTMAX

OUTMIN

OUT

V

V

Drift

10 (ppm)

V

Temperature Range

æ

ö

-

=

×

ç

÷

×

è

ø

V

=

HYST

· 10 (ppm)

6

abs|V

V

|

PRE

POST

-

V

NOM

11

REF3112, REF3120, REF3125

REF3130, REF3133, REF3140

www.ti.com

SBVS046D – DECEMBER 2003 – REVISED MARCH 2016

Product Folder Links: REF3112 REF3120 REF3125 REF3130 REF3133 REF3140

Submit Documentation Feedback

Copyright © 2003–2016, Texas Instruments Incorporated

Feature Description (continued)

Supply voltages below the specified levels can cause the REF31xx to momentarily draw currents greater than

the typical quiescent current. This can be prevented by using a power supply with a fast rising edge and low

output impedance.

8.3.2 Thermal Hysteresis

Thermal hysteresis for the REF31xx 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:

Where:

VHYST = Thermal hysteresis.

VPRE = Output voltage measured at 25°C pretemperature cycling.

VPOST = Output voltage measured after the device has been cycled through the specified temperature

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

(1)

8.3.3 Temperature Drift

The REF31xx is designed to exhibit minimal drift error, defined as the change in output voltage over varying

temperature. The drift is calculated using the box method, which is described in Equation 2:

(2)

The REF31xx features a typical drift coefficient of 5 ppm from 0°C to 70°C, the primary temperature range for

many applications. For the industrial temperature range of –40°C to +125°C, the REF31xx family drift increases

to a typical value of 10 ppm.

8.3.4 Noise Performance

Typical 0.1-Hz to 10-Hz voltage noise can be seen in Figure 21. The noise voltage of the REF31xx increases

with output voltage and operating temperature. Additional filtering may be used to improve output noise levels,

although take care to ensure the output impedance does not degrade the AC performance.

Figure 21. 0.1-Hz to 10-Hz Noise