AD565A

REV.

–10–

FIGURE 6. OTHER VOLTAGE RANGES

The AD566A can also be easily configured for a unipolar 0 V to

+5 V range or

±2.5 V and ±10 V bipolar ranges by using the

additional 5 k

Ω application resistor provided at the 20 V span R

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

±2.5 V), the two

5 k

Ω 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

range. For the

±10 V range (20 V span), use the 5 kΩ resistors in

series by connecting only Pin 11 to the op amp output and the

bipolar offset connected as shown. The

±10 V option is shown

in Figure 6.

Table I. Digital Input Codes

DIGITAL INPUT

ANALOG OUTPUT

MSB

LSB

Straight Binary

Offset Binary

Twos Complement

*

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.

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 *

Figure 6.

±10 V Voltage Output

F