+

+

±

+

±

IN OUT

REF3012

IN

OUT

REF3030

3.3 V

1.25 V

20 k

3.0 V

20 k

OPA317

100 k

10 k

3.0 V

1.25 V

3.3 V

IN+

IN±

SD_16

J1.2/A1+

J1.3/A1±

0.625 V

47 µF

47 k

47 k

±5 V

A-ADC

3.0 V

MSP430F2013

Launchpad

100 k

1

3

REF30xx

2

0.47

F

m

V

IN

V

OUT

REF3012, REF3020, REF3025, REF3030, REF3033, REF3040

www.ti.com

SBVS032G – MARCH 2002 – REVISED NOVEMBER 2015

9 Application and Implementation

9.1 Application Information

For normal operation, the REF30xx does not require a capacitor on the output. If a capacitive load is connected,

take special care when using low equivalent series resistance (ESR) capacitors and high capacitance. This

precaution is especially true for low-output voltage devices; therefore, for the REF3012 use a low-ESR

capacitance of 10

μF or less. Figure 29 shows the typical connections required for operation of the REF30xx. A

supply bypass capacitor of 0.47

μF is always recommended.

Figure 29. Typical Connections for Operating REF30xx

9.2 Typical Application

Figure 30 shows a low-power reference and conditioning circuit. This circuit attenuates and level-shifts a bipolar

input voltage within the proper input range of a single-supply low power 16-Bit

ΔΣ ADC, such as the one inside

the MSP430 or other similar single-supply ADCs. Precision reference circuits are used to level-shift the input

signal, provide the ADC reference voltage and to create a well-regulated supply voltage for the low-power analog

circuitry. A low-power, zero-drift, op-amp circuit is used to attenuate and level-shift the input signal.

Figure 30. Low-Power Reference and Bipolar Voltage Conditioning Circuit for Low-Power ADCs

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Product Folder Links: REF3012 REF3020 REF3025 REF3030 REF3033 REF3040