AD7628

–5–

REV. A

Table I. Unipolar Binary Code Table

DAC Latch Contents

Analog Output

MSB

LSB

(DAC A or DAC B)

1 1 1 1 1 1 1 1

–V

IN

255

256









1 0 0 0 0 0 0 1

–V

IN

129

256









1 0 0 0 0 0 0 0

–V

IN

128

256









= –

V

IN

2

0 1 1 1 1 1 1 1

–V

IN

127

256









0 0 0 0 0 0 0 1

–V

IN

1

256









0 0 0 0 0 0 0 0

–V

IN

0

256









= 0

1

256

V

IN

()

Figure 4. Dual DAC Unipolar Binary Operation (2 Quadrant Multiplication). See Table I.

Figure 5. Dual DAC Bipolar Operation (4 Quadrant Multiplication). See Table II.

Table II. Bipolar (Offset Binary) Code Table

DAC Latch Contents

Analog Output

MSB

LSB

(DAC A or DAC B)

1 1 1 1 1 1 1 1

+V

IN

127

128









1 0 0 0 0 0 0 1

+V

IN

1

128









1 0 0 0 0 0 0 0

0

0 1 1 1 1 1 1 1

–V

IN

1

128









0 0 0 0 0 0 0 1

–V

IN

127

128









0 0 0 0 0 0 0 0

–V

IN

128

128









NOTE: 1 LSB = (2

1

128

V

IN

()

Table III. Recommended Trim Resistor Values

Trim

Resistor

K/B/T

R1; R3

500

R2; R4

150