10-12

Unipolar Binary Operation - AD7533 (10-Bit DAC)

The circuit configuration for operating the AD7533 in

unipolar mode is shown in Figure 2. With positive and

multiplication. The “Digital Input Code/Analog Output Value”

table for unipolar mode is given in Table 2.

Zero Offset Adjustment

1. Connect all digital inputs to GND.

2. Adjust the offset zero adjust trimpot of the output

operational amplifier for 0V

Gain Adjustment

1. Connect all digital inputs to V+.

250

250

terminal.

Bipolar (Offset Binary) Operation - AD7523

The circuit configuration for operating the AD7523 in the

bipolar mode is given in Figure 3. Using offset binary digital

input codes and positive and negative reference voltage

values, Four-Quadrant multiplication can be realized. The

“Digital Input Code/Analog Output Value” table for bipolar

mode is given in Table 3.)

A “Logic 1” input at any digital input forces the corresponding

output sums the two currents. This configuration doubles the

output range. The difference current resulting at zero offset

binary code, (MSB = “Logic 1”, all other bits = “Logic 0”), is

corrected by suing an external resistor, (10M

TABLE 2. UNlPOLAR BINARY CODE - AD7533

DIGITAL INPUT

MSB

LSB

(NOTE 1)

NOMINAL ANALOG OUTPUT

1111111111

1000000001

1000000000

0111111111

0000000001

0000000000

NOTES:

2. Nominal Full Scale for the circuit of Figure 2 is given by:

.

3. Nominal LSB magnitude for the circuit of Figure 2 is given by:

.

V

REF

1023

1024

-------------





–

V

REF

513

1024

-------------





–

V

REF

512

1024

-------------





–

V

REF

2

---------------

–

=

V

REF

511

1024

-------------





–

V

REF

1

1024

-------------





–

V

REF

0

1024

-------------





–

0

=

FS

V

REF

1023

1024

-------------





–

=

LSB

V

REF

1

1024

-------------





=

TABLE 3. BlPOLAR (OFFSET BINARY) CODE - AD7523

DIGITAL INPUT

MSB

LSB

ANALOG OUTPUT

11111111

10000001

10000000

0

01111111

00000001

00000000

NOTE:

1.

.

V

REF

127

128

----------





–

V

REF

1

128

----------





–

+V

REF

1

128

----------





+V

REF

127

128

----------





+V

REF

128

128

----------





1 LSB

2

7

–

() V

REF

()

1

128

----------



 V

REF

()

==

6

6

-

+

CR1

15

16

1

4

13

3

2

AD7523/

MSB

LSB

14

+15V

DATA

INPUTS

AD7533

±10V

R3 5K

R4 5K

R2

CR2

R1

R6 10M

Ω

FIGURE 3. BIPOLAR OPERATION (4-QUADRANT MULTIPLICATION)

-

+

AD7523, AD7533