max530bcwgt Maxim Integrated Products, Inc., max530bcwgt Datasheet - Page 14

• Manufacturer Part Number: max530bcwgt
• Description: Max530 +5v, Low-power, Parallel-input, Voltage-output, 12-bit Dac
• Manufacturer: Maxim Integrated Products, Inc.

+5V, Low-Power, Parallel-Input,
Voltage-Output, 12-Bit DAC
Table 3. Unipolar Binary Code Table
(0V to V
A -V
necting ROFS to REFIN and RFB to VOUT, and operat-
ing from dual (±5V) supplies (Figure 11). Table 5
shows the DAC-latch contents (input) vs. VOUT (out-
put). In this range, 1 LSB = REFIN (2
The MAX530 can be used as a four-quadrant multiplier
by connecting ROFS to REFIN and RFB to VOUT and,
using (1) an offset binary digital code, (2) bipolar
power supplies, and (3) a bipolar analog input at
REFIN within the range V
in Figure 12.
In general, a 12-bit DAC’s output is (D)(V
where “G” is the gain (1 or 2) and “D” is the binary rep-
resentation of the digital input divided by 2
This formula is precise for unipolar operation. However,
for bipolar, offset binary operation, the MSB is really a
polarity bit. No resolution is lost, because there is the
same number of steps. The output voltage, however,
has been shifted from a range of, for example, 0V to
4.096V (G = 2) to a range of -2.048V to +2.048V.
Keep in mind that when using the DAC as a four-quad-
rant multiplier, the scale is skewed. The negative full
scale is -V
- 1LSB.
14
REFIN
______________________________________________________________________________________
1111
1000
1000
0111
0000
0000
REFIN
REFIN
to +V
INPUT
1111
0000
0000
1111
0000
0000
, while the positive full scale is +V
REFIN
Output), Gain = 1
Four-Quadrant Multiplication
1111
0001
0000
1111
0000
0001
bipolar range is set up by con-
SS
Bipolar Configuration
+ 2V to V
(V
REFIN
(V
(V
(V
(V
REFIN
REFIN
REFIN
REFIN
OUTPUT
)
DD
2048
4096
-11
OV
)
)
)
)
4096
2047
4096
4095
4096
2049
4096
).
- 2V, as shown
= +V
1
12
REFIN
REFIN
or 4,096.
/2
REFIN
)(G),
Table 4. Unipolar Binary Code Table
(0V to 2V
Table 5. Bipolar (Offset Binary) Code Table
(-V
REFIN
1111
1000
1000
0111
0000
1111
1000
1000
0111
0000
0000
0000
REFIN
to +V
INPUT
INPUT
1111
0000
0000
1111
0000
0000
1111
0000
0000
1111
0000
0000
REFIN
Output), Gain = 2
1111
0001
0000
1111
0000
1111
0001
0000
1111
0000
0001
0001
Output)
+2 (V
+2 (V
+2 (V
+2 (V
+2 (V
(+V
(+V
(-V
(-V
(-V
REFIN
REFIN
REFIN
REFIN
REFIN
REFIN
REFIN
REFIN
REFIN
OUTPUT
REFIN
OUTPUT
OV
0V
)
)
)
)
)
)
)
)
)
)
2048
2047
2048
2048
2047
2048
2048
2048
4096
4095
4096
2049
4096
2048
4096
2047
4096
1
1
1
= -V
= +V
REFIN
REFIN