AD565A/AD566A

REV. D

–8–

FIGURE 1. UNIPOLAR CONFIGURATION

This configuration will provide a unipolar 0 volt to +10 volt

output range. In this mode, the bipolar terminal, Pin 8, should

be grounded if not used for trimming.

19.95k

20k

0.5mA

DAC

4

CODE

AD565A

9.95k

5k

8k

20V SPAN

10V SPAN

DAC

OUT

POWER

GND

REF

GND

BIPOLAR OFF

5k

CODE

INPUT

LSB

MSB

10V

REF

OUT

REF

IN

R2

100

10pF

AD509

OUTPUT

0V TO

+10V

100

100k

+15V

–15V

R1

50k

2.4k

Figure 1. 0 V to +10 V Unipolar Voltage Output

STEP I . . . ZERO ADJUST

Turn all bits OFF and adjust zero trimmer R1, until the output

reads 0.000 volts (1 LSB = 2.44 mV). In most cases this trim is

not needed, but Pin 8 should then be connected to Pin 12.

STEP II . . . GAIN ADJUST

Turn all bits ON and adjust 100

Ω gain trimmer R2, until the

output is 9.9976 volts. (Full scale is adjusted to 1 LSB less than

nominal full scale of 10.000 volts.) If a 10.2375 V full scale is

desired (exactly 2.5 mV/bit), insert a 120

Ω resistor in series

with the gain resistor at Pin 10 to the op amp output.

FIGURE 2. BIPOLAR CONFIGURATION

This configuration will provide a bipolar output voltage from

–5.000 to +4.9976 volts, with positive full scale occurring with

all bits ON (all 1s).

19.95k

20k

0.5mA

DAC

4

CODE

AD565A

9.95k

5k

8k

20V SPAN

10V SPAN

DAC

OUT

POWER

GND

REF

GND

BIPOLAR OFF

5k

CODE

INPUT

LSB

MSB

10V

REF

OUT

REF

IN

R2

100

10pF

AD509

OUTPUT

–5V TO

+5V

2.4k

R1

100

Figure 2.

±5 V Bipolar Voltage Output

STEP I . . . OFFSET ADJUST

Turn OFF all bits. Adjust 100

Ω trimmer R1 to give –5.000

volts output.

STEP II . . . GAIN ADJUST

Turn ON All bits. Adjust 100

Ω gain trimmer R2 to give a read-

ing of +4.9976 volts.

Please note that it is not necessary to trim the op amp to obtain

full accuracy at room temperature. In most bipolar situations,

an op amp trim is unnecessary unless the untrimmed offset drift

of the op amp is excessive.

FIGURE 3. OTHER VOLTAGE RANGES

The AD565A can also be easily configured for a unipolar 0 volt

to +5 volt range or

±2.5 volt and ±10 volt bipolar ranges by

using the additional 5k application resistor provided at the 20

volt span R terminal, Pin 11. For a 5 volt span (0 to +5 or

±2.5), the two 5k resistors are used in parallel by shorting Pin

11 to Pin 9 and connecting Pin 10 to the op amp output and the

bipolar offset either to ground for unipolar or to REF OUT for

the bipolar offset either to ground for unipolar or to REF OUT

for the bipolar range. For the

±10 volt range (20 volt span) use

the 5k resistors in series by connecting only Pin 11 to the op

amp output and the bipolar offset connected as shown. The

±10

volt option is shown in Figure 3.

19.95k

20k

0.5mA

DAC

4

CODE

AD565A

9.95k

5k

8k

20V SPAN

10V SPAN

DAC

OUT

POWER

GND

REF

GND

BIPOLAR OFF

5k

CODE

INPUT

LSB

MSB

10V

REF

OUT

REF

IN

R2

100

10pF

AD509

OUTPUT

–10V TO

+10V

3.0k

R1

100

Figure 3.

±10 V Voltage Output