REF3212-EP Datasheet, PDF (15/22 Pages) Texas Instruments – 4 ppm/°C, 100 μA SOT23-6 SERIES VOLTAGE REFERENCES

REF3212-EP, REF3220-EP, REF3225-EP
REF3230-EP, REF3233-EP, REF3240-EP
www.ti.com
SBVS078B – OCTOBER 2006 – REVISED AUGUST 2011
APPLICATION CIRCUITS
Negative Reference Voltage
For applications requiring a negative and positive reference voltage, the REF32xx and OPA735 can be used to
provide a dual-supply reference from a 5-V supply. Figure 8 shows the REF3225 used to provide a 2.5-V supply
reference voltage. The low drift performance of the REF32xx complements the low offset voltage and zero drift of
the OPA735 to provide an accurate solution for split-supply applications. Care must be taken to match the
temperature coefficients of R₁ and R₂.
+5 V
34
5
REF3225 6
21
R₁
10 kW _R2
10 kW
+5 V
+2.5 V
OPA735
-2.5 V
-5 V
Note: Bypass capacitor is not shown.
Figure 8. REF3225 Combined With OPA735 to Create Positive and Negative Reference Voltages
Data Acquisition
Data acquisition systems often require stable voltage references to maintain accuracy. The REF32xx family
features stability and a wide range of voltages suitable for most microcontrollers and data converters. Figure 9,
Figure 10, and Figure 11 show basic data acquisition systems.
5W
ADS7822
V_REF
V_CC
0.1 mF
+
1 mF to 10 mF
3.3 V
V_S
5
3
6 ^REF3233 4
21
GND
+
1 mF to 10 mF
V+
0.47 mF
V_IN
+In
CS
-In
D_OUT
GND DCLOCK
Microcontroller
Figure 9. Basic Data Acquisition System 1
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Product Folder Link(s): REF3212-EP, REF3220-EP, REF3225-EP REF3230-EP, REF3233-EP, REF3240-EP