Datasheet

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
NOTE: 1 LSB = (2
–8
)(V
IN
) =
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
–7
)(V
IN
) =
1
128
V
IN
()
Table III. Recommended Trim Resistor Values
Trim
Resistor K/B/T
R1; R3 500
R2; R4 150