Datasheet

V
IN
REF3312
R
1
100 k
R
3
20 k
C
1
0.15 F
R
4
100 k
R
5
10 k
SD_16
û-ADC
R
8
1 k
R
2
20 k
IN OUT
+1.25 V
_
±5 V
+1.25 V
REF3330
IN OUT
3.0 V
3.3 V
+3.0 V
R
6
47 k
0.625 V
+
C
2
47 F
+3.0 V
3.3 V
V
OUT
IN+
IN±
V
REF
MSP430F2013 LaunchPad
J1.2/A1+
J1.3/A1±
J1.5/VREF
OPA317
+
±
R
7
47 k
+
REF3312 , REF3318 , REF3320 , REF3325 , REF3330 , REF3333
SBOS392D –AUGUST 2007–REVISED JUNE 2014 www.ti.com
10 Applications and Implementation
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
12 Submit Documentation Feedback Copyright © 2007–2014, Texas Instruments Incorporated
Product Folder Links: REF3312 REF3318 REF3320 REF3325 REF3330 REF3333