ADDAC80/ADDAC85/ADDAC87
1
2
3
4
12-BIT
5 RESISTOR
6 LADDER
NETWORK
7
AND
CURRENT
8 SWITCHES
9
10
11
12
24
REF
CONTROL 23
CIRCUIT 22
21
5k⍀
20
2k⍀
19
3k⍀ 18
17
6.3k⍀
16
15
14
13
+VS
10M⍀
10k⍀
TO
0.01F 100k⍀
–VS
10k⍀
TO
100k⍀
+VS
1F
3.9M⍀
–VS
1F
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.
1
2
3
4
12-BIT
5 RESISTOR
6 LADDER
NETWORK
7
AND
CURRENT
8 SWITCHES
9
10
11
12
24
REF
CONTROL 23
CIRCUIT 22
21
5k⍀
20
19
5k⍀
18
17
6.3k⍀
16
–
15
+
14
13
10M⍀
0.01F
3.9M⍀
1F
+VS
10k⍀
TO
100k⍀
–VS
10k⍀
TO
100k⍀
+VS
–VS
1F
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
Voltage*
Current
MSB
LSB
000000000000
011111111111
100000000000
111111111111
l LSB
0 to +10 V
+9.9976 V
+5.0000 V
+4.9976 V
0.0000 V
2.44 mV
؎10 V
+9.9951 V
0.0000 V
4.88 mV
–10.0000 V
–0.0049 V
0 to –2 mA
–1.9995 mA
–1.0000 mA
–0.9995 mA
0.0000 mA
0.488 µA
؎1 mA
–0.9995 mA
0.0000 mA
+0.0005 mA
–1.00 mA
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.
–10–
REV. B