Output Pin

Meter

V

OUT

+

Sense Line

Force Line

Load

I

L

Contact and

Trace Resistance

PRE

POST

6

HYST

NOM

abs V

V

V

=

• 10 (ppm)

V

æ

ö

-

ç

÷

ç

÷

è

ø

REF3012, REF3020, REF3025, REF3030, REF3033, REF3040

SBVS032G – MARCH 2002 – REVISED NOVEMBER 2015

www.ti.com

Feature Description (continued)

8.3.2 Thermal Hysteresis

Thermal hysteresis for the REF30xx 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, and can be expressed

as shown in Equation 1:

where

•

•

•

–40°C to +125°C, and returned to operation at 25°C.

(1)

8.3.3 Temperature Drift

The REF30xx exhibits minimal drift error, defined as the change in output voltage over varying temperature.

Using the box method of drift measurement, the REF30xx features a typical drift coefficient of 20 ppm from 0°C

to 70°C, the primary temperature range of use for many applications. For industrial temperature ranges of –40°C

to +125°C, the REF30xx family drift increases to a typical value of 50 ppm.

8.3.4 Noise Performance

The REF30xx generates noise less than 50

Figure 20 The noise voltage of the REF30xx increases with output voltage and operating temperature. Additional

filtering may be used to improve output noise levels; however, ensure the output impedance does not degrade ac

performance.

8.3.5 Long-Term Stability

Long-term stability refers to the change of the output voltage of a reference over a period of months or years.

This effect lessens as time progresses as is apparent by the long term stability curves. The typical drift value for

the REF30xx is 24 ppm from 0 hours to 1000 hours, and 15 ppm from 1000 hours to 2000 hours. This parameter

is characterized by measuring 30 units at regular intervals for a period of 2000 hours.

8.3.6 Load Regulation

Load regulation is defined as the change in output voltage as a result of changes in load current. Load regulation

for the REF30xx is measured using force and sense contacts as shown in Figure 25. The force and sense lines

tied to the contact area of the output pin reduce the impact of contact and trace resistance, resulting in accurate

measurement of the load regulation contributed solely by the REF30xx. For applications requiring improved load

regulation, use force and sense lines.

Figure 25. Accurate Load Regulation of REF30xx

12

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