+2.5V

+5V

1

2

5

6

3

4

Note:Bypasscapacitorisnotshown.

R

1

10k

W

R

2

10k

W

+5V

OPA735

REF3225

-

2.5V

-

5V

ADS7822

REF3233

V

CC

CS

D

OUT

DCLOCK

V

REF

+In

-In

GND

GND

V

IN

V

S

+

+

5 W

1 Fto10 F

m

m

0.1 F

m

V+

3.3V

2

1

3

5

6

4

Microcontroller

1 Fto10 F

m

m

0.47 F

m

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

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.

Figure 9. Basic Data Acquisition System 1

Copyright

© 2006–2011, Texas Instruments Incorporated

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Product Folder Link(s): REF3212-EP, REF3220-EP, REF3225-EP REF3230-EP, REF3233-EP, REF3240-EP

Not Recommended For

New Designs