AD565A/AD566A
FIGURE 1. UNIPOLAR CONFIGURATION
STEP I . . . OFFSET ADJUST
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.
+15V
100k
100
REF
OUT
V
CC
BIPOLAR OFF
20V SPAN
9.95k
R2
100
10V
5k
5k
10pF
I
O
8k
DAC
OUT
AD509
2.4k
OUTPUT
0V TO
+10V
10V SPAN
R1
50k
–15V
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
AD565A
19.95k
0.5mA
I
REF
20k
REF
IN
REF
GND
DAC
I
OUT
=
4 I
REF
CODE
CODE
INPUT
MSB
POWER
GND
–V
EE
LSB
Figure 1. 0 V to +10 V Unipolar Voltage Output
STEP I . . . ZERO ADJUST
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.
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
REF
OUT
V
CC
R1
100
BIPOLAR OFF
20V SPAN
9.95k
R2
100
10V
5k
5k
10V SPAN
10pF
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
AD565A
19.95k
0.5mA
I
REF
20k
I
O
8k
REF
IN
REF
GND
DAC
OUT
AD509
3.0k
OUTPUT
–10V TO
+10V
DAC
I
OUT
=
4 I
REF
CODE
CODE
INPUT
MSB
LSB
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).
POWER
GND
–V
EE
Figure 3.
±
10 V Voltage Output
REF
OUT
V
CC
R1
100
BIPOLAR OFF
20V SPAN
9.95k
R2
100
10V
5k
5k
10pF
I
O
8k
DAC
OUT
AD509
2.4k
OUTPUT
–5V TO
+5V
10V SPAN
AD565A
19.95k
0.5mA
I
REF
20k
REF
IN
REF
GND
DAC
I
OUT
=
4 I
REF
CODE
CODE
INPUT
MSB
LSB
POWER
GND
–V
EE
Figure 2.
±
5 V Bipolar Voltage Output
–8–
REV. D
AD [ ANALOG DEVICES ]
