+

+

±

+

±

IN OUT

REF3112

IN

OUT

REF3130

3.3 V

R2

R1

1.25 V

20 k

R3

3.0 V

VOUT

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±

J1.5/VREF

0.625 V

C2

47 µF

R6

47 k

R7

47 k

VIN

±5 V

R4

A-ADC

R5

3.0 V

MSP430F2013

Launchpad

100 k

1

3

REF31xx

2

0.47 F

m

V

IN

V

OUT

15

REF3112, REF3120, REF3125

REF3130, REF3133, REF3140

www.ti.com

SBVS046D – DECEMBER 2003 – REVISED MARCH 2016

Product Folder Links: REF3112 REF3120 REF3125 REF3130 REF3133 REF3140

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Copyright © 2003–2016, Texas Instruments Incorporated

9 Application and Implementation

NOTE

Information in the following applications sections is not part of the TI component

specification, and TI does not warrant its accuracy or completeness. TI’s customers are

responsible for determining suitability of components for their purposes. Customers should

validate and test their design implementation to confirm system functionality.

9.1 Application Information

The REF31xx does not require a load capacitor and is stable with any capacitive load. Figure 28 shows typical

connections required for operation of the REF31xx. TI recommends a supply bypass capacitor of 0.47

μF.

Figure 28. Typical Connections for Operating REF31xx

9.2 Typical Application

Figure 29 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 29. Low-Power Reference and Bipolar Voltage Conditioning Circuit for Low-Power ADCs