VIN

REF3312

R1

100 k

R3

20 k

C1

0.15 …F

R4

100 k

R5

10 k

SD_16

û-ADC

R8

1 k

R2

20 k

IN

OUT

+1.25 V

_

±5 V

+1.25 V

REF3330

IN

OUT

3.0 V

3.3 V

+3.0 V

R6

47 k

0.625 V

+

C2

47 …F

+3.0 V

3.3 V

VOUT

IN+

IN±

MSP430F2013 LaunchPad

J1.2/A1+

J1.3/A1±

J1.5/VREF

OPA317

+

±

R7

47 k

+

13

REF3312, REF3318, REF3320, REF3325, REF3330, REF3333

www.ti.com

SBOS392H – AUGUST 2007 – REVISED AUGUST 2019

Product Folder Links: REF3312 REF3318 REF3320 REF3325 REF3330 REF3333

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Copyright © 2007–2019, Texas Instruments Incorporated

10 Applications 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.

10.1 Application Information

The REF33xx is a family of low-power, precision band-gap voltage references that are specifically designed for

extremely low dropout, excellent initial voltage accuracy with a high output current. The extremely small size of

the SC70-3, SOT-23-3, and UQFN-8 make these references very attractive for space-constrained applications.

The following section describes one common application.

10.2 Typical Applications

10.2.1 REF3312 in a Bipolar Signal-Chain Configuration

The circuit in Figure 19 consists of 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 analog-

to-digital converter (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 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 19. Bipolar Signal-Chain Configuration