0

10

20

30

40

V

REF and VBIAS Matching (ppm)

C004

0

10

20

30

40

50

60

0

1

2

3

4

5

6

V

REF and VBIAS Tracking Over Temperature (ppm/ƒC)

C016

20

REF1925, REF1930, REF1933, REF1941

SBOS697A – SEPTEMBER 2014 – REVISED JANUARY 2017

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Product Folder Links: REF1925 REF1930 REF1933 REF1941

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Copyright © 2014–2017, Texas Instruments Incorporated

Typical Application (continued)

10.2.2.3 Voltage Reference

The voltage reference for this application must have the following features:

1. Dual output (3.0 V and 1.5 V),

2. Low drift, and

3. Low tracking errors between the two outputs.

For this design, the REF1930 is used. The REF19xx topology is as shown in the Functional Block Diagram

section.

The REF1930 is an excellent choice for this application because of its dual output. The temperature drift of

25 ppm/°C and initial accuracy of 0.1% make the errors resulting from the voltage reference minimal in this

application. In addition, there is minimal mismatch between the two outputs and both outputs track very well

across temperature, as shown in Figure 48 and Figure 49.

Figure 48. VREF – 2 × VBIAS Distribution (At TA = 25°C)

Figure 49. Distribution of VREF – 2 × VBIAS Drift Tracking

Over Temperature

10.2.2.4 Results

Table 1 summarizes the measured results.

Table 1. Measured Results

ERROR

UNCALIBRATED (%)

CALIBRATED (%)

Error across the full load current range (25°C)

±0.0355

±0.004

Error across the full load current range (–40°C to 125°C)

±0.0522

±0.0606