AD565A/AD566A
STEP I . . . OFFSET ADJUST
Turn OFF all bits. Adjust 100 Ω trimmer R1 to give –5.000
volts output.
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.
STEP II . . . GAIN ADJUST
Turn ON All bits. Adjust 100 Ω gain trimmer R2 to give a read-
ing of +4.9976 volts.
+15V
100k⍀
R1
50k⍀
100⍀
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.
–15V
REF
OUT
V
BIPOLAR OFF
CC
20V SPAN
5k⍀
5k⍀
9.95k⍀
10V SPAN
FIGURE 3. OTHER VOLTAGE RANGES
R2
10V
100⍀
AD565A
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.
10pF
OUTPUT
0V TO
+10V
19.95k⍀
0.5mA
DAC
OUT
I
O
8k⍀
REF
IN
I
AD509
2.4k⍀
REF
DAC
I
=
OUT
20k⍀
REF
GND
REF
CODE
INPUT
POWER
GND
–V
EE
MSB
LSB
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.
R1
REF
V
100⍀
BIPOLAR OFF
CC
OUT
20V SPAN
10V SPAN
5k⍀
5k⍀
9.95k⍀
STEP II . . . GAIN ADJUST
R2
100⍀
10V
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.
AD565A
10pF
OUTPUT
–10V TO
+10V
19.95k⍀
0.5mA
DAC
OUT
I
O
8k⍀
REF
IN
I
AD509
REF
DAC
I
=
OUT
3.0k⍀
20k⍀
REF
GND
REF
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).
CODE
INPUT
POWER
GND
–V
EE
MSB
LSB
Figure 3. 10 V Voltage Output
R1
100⍀
REF
OUT
V
BIPOLAR OFF
CC
20V SPAN
10V SPAN
5k⍀
5k⍀
9.95k⍀
R2
100⍀
10V
AD565A
10pF
OUTPUT
–5V TO
+5V
19.95k⍀
0.5mA
DAC
OUT
I
O
8k⍀
REF
IN
I
AD509
2.4k⍀
REF
DAC
I
=
OUT
20k⍀
REF
GND
REF
CODE
INPUT
POWER
GND
–V
EE
MSB
LSB
Figure 2. 5 V Bipolar Voltage Output
–8–
REV. D
ADI [ ADI ]
