AD565A/AD566A

REV. D

–10–

FIGURE 6. OTHER VOLTAGE RANGES

The AD566A 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 V to +5 V or

±2.5 V), 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

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 6.

19.95k

20k

0.5mA

DAC

4

CODE

AD566A

9.95k

5k

8k

20V SPAN

10V SPAN

DAC

OUT

POWER

GND

REF

GND

BIPOLAR OFF

5k

CODE

INPUT

LSB

MSB

R2

5k

10pF

AD509

2.4k

AD561

–V

REF

IN

R1

5k

14k

AND R3 ESTABLISHES A CURRENT TO BALANCE THE MSB CURRENT.

THE EFFECT OF TEMPERATURE COEFFICIENT MISMATCH BETWEEN

THE BIPOLAR RESISTOR COMBINATION AND DAC RESISTORS IS

EXPANDED ON PREVIOUS PAGE.

R3

26k *

Fgure 6.

±10 V Voltage Output

Table I. Digital Input Codes

DIGITAL INPUT

ANALOG OUTPUT

MSB

LSB

Straight Binary

Offset Binary

Twos Compl.*

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

Zero

–FS

Zero

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

Mid Scale – 1 LSB

Zero – 1 LSB

+FS – 1 LSB

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

+1/2 FS

Zero

–FS

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

+FS – l LSB

+ FS – 1 LSB

Zero – 1 LSB

*Inverts the MSB of the offset binary code with an external inverter to obtain

twos complement.