REV. B

ADDAC80/ADDAC85/ADDAC87

–10–

1 F

3.9M

1 F

0.01 F

10M

10k

TO

100k

10k

TO

100k

1

2

3

4

5

6

7

8

9

10

11

12

12-BIT

RESISTOR

LADDER

NETWORK

AND

CURRENT

SWITCHES

REF

CONTROL

CIRCUIT

6.3k

2k

3k

5k

24

23

22

21

20

19

18

17

16

15

14

13

Figure 6. External Adjustment and Voltage Supply

Connection Diagram, Current Model

Offset Adjustment

For unipolar (CSB) configurations, apply the digital input code

that should produce zero potential output and adjust the

OFFSET potentiometer for zero output. For bipolar (COB, CTC)

configurations, apply the digital input code that should produce

the maximum negative output voltage. Example: If the FULL

SCALE RANGE is connected for 20 V, the maximum negative

output voltage is –10 V. See Table II for corresponding codes.

Gain Adjustment

For either unipolar or bipolar configurations, apply the digital

input that should give the maximum positive voltage output.

Adjust the GAIN potentiometer for this positive full-scale voltage.

See Table II for positive full-scale voltages.

12-BIT

RESISTOR

LADDER

NETWORK

AND

CURRENT

SWITCHES

REF

CONTROL

CIRCUIT

1

2

3

4

5

6

7

8

9

10

11

12

24

23

22

21

20

19

18

17

16

15

14

13

6.3k

5k

5k

+

–

1 F

1 F

0.01 F

10M

10k

TO

100k

10k

TO

100k

3.9M

Figure 7. External Adjustment and Voltage Supply

Connection Diagram, Voltage Model

10M

270k

270k

7.8k

3.9M

180k

180k

10k

Figure 8. Equivalent Resistances

Table II. Digital Input Analog Output

Digital Input

Analog Output

12-Bit Resolution

Current

MSB

LSB

0 to +10 V

10 V

0 to –2 mA

1 mA

0 0 0 0 0 0 0 0 0 0 0 0

+9.9976 V

+9.9951 V

–1.9995 mA

–0.9995 mA

0 1 1 1 1 1 1 1 1 1 1 1

+5.0000 V

0.0000 V

–1.0000 mA

0.0000 mA

1 0 0 0 0 0 0 0 0 0 0 0

+4.9976 V

4.88 mV

–0.9995 mA

+0.0005 mA

1 1 1 1 1 1 1 1 1 1 1 1

0.0000 V

–10.0000 V

0.0000 mA

–1.00 mA

l LSB

2.44 mV

–0.0049 V

0.488

µA

0.488

µA

*To obtain values for other binary ranges 0 to 5 V range: divide 0 to 10 values by 2;

± 5 V range: divide

± 10 V range values by 2; ±2.5 V range: divide ±10 V range values by 4.