DAC8412/DAC8413

–12–

REV. D

Careful attention to grounding is important to accurate opera-

tion of the DAC8412. This is not because the DAC8412 is

more sensitive than other 12-bit DACs, but because with four

outputs and two references there is greater potential for ground

loops. Since the DAC8412 has no analog ground, the ground

must be specified with respect to the reference.

Reference Configurations

Output voltage ranges can be configured as either unipolar or

bipolar, and within these choices a wide variety of options exists.

The unipolar configuration can be either positive or negative

voltage output, and the bipolar configuration can be either sym-

metrical or nonsymmetrical.

OP-400

REF10

+15V

INPUT

OUTPUT

TRIM

10k

0.2 F

+10V OPERATION

+

+15V

DAC8412

OR

DAC8413

0.1 F

//10 F

OP400

–15V

Figure 36. Unipolar +10 V Operation

DAC A

DAC B

DAC C

DAC D

OUTPUT

REGISTER

WRDB0

WRDB1

WRDB2

WRDB3

WRDB4

WRDB5

WRDB6

WRDB7

WRDB8

WRDB9

WRDB10

RDDACB

INPUT

REGISTER

RDDACA

WRDACA

WRDACB

RDDACC

WRDACC

RDDACD

WRDACD

WRDB11

READBACKDATAIN_DB10

READOUT

READOUTBAR

READBACKDATAIN_DB11

READBACK

DATAOUT_DB11

DB11..DB0

R/

W

A1

A0

CS

LDAC

RESET

DGND

Figure 35. Simplified I/O Logic Diagram

+15V

1 F

0.2 F

10V

5V

39k

6.2

6.2

BALANCE

100k

GAIN

100k

0.2 F

0.1 F

//10 F

DAC8412

OR

DAC8413

+15V

–15V

5 OR

10V OPERATION

Figure 37. Symmetrical Bipolar Operation

Figure 37 (Symmetrical Bipolar Operation) shows the DAC8412

configured for

± 10 V operation. Note: See the AD688 data

sheet for a full explanation of reference operation. Adjustments may

not be required for many applications since the AD688 is a very

high accuracy reference. However if additional adjustments are

required, adjust the DAC8412 full scale first. Begin by loading

Adjust potentiometer to attain a DAC output voltage of 9.9976 V.

Then, adjust the Balance Adjust to set the center scale output

voltage to 0.000 V.