DAC80 Burr-Brown Corporation, DAC80 Datasheet - Page 7

• Manufacturer Part Number: DAC80
• Description: Monolithic 12-Bit DIGITAL-TO-ANALOG CONVERTERS
• Manufacturer: Burr-Brown Corporation

FIGURE 4. Equivalent Resistances.
Existing applications that are converting to the monolithic
DAC80 must change the gain trim resistor on pin 23 from
33M
23 is a high impedance point and a 0.001 1F to 0.01 F
ceramic capacitor should be connected from this pin to
Common (pin 21) to prevent noise pickup. Refer to Figure
5 for relationship of Offset and Gain adjustments to unipolar
and bipolar D/A operation.
FIGURE 5. Relationship of Offset and Gain Adjustments for
Unipolar
Bipolar
Offset Adjust Translates the Line
Range
of Offset
Adjust
Range of
Offset Adjust
Offset Adjust Translates the Line
1LSB
to 10M
All Bits
Logic 1
3.9M
10M
a Unipolar and Bipolar D/A Converter.
All Bits
Logic 1
+ Full Scale
Bipolar
Offset
to insure sufficient adjustment range. Pin
Full Scale
1LSB
Range
Digital Input
Digital Input
270k
180k
+ Full Scale
MSB On,
All Others
Off
–Full Scale
Rotates the Line
7.8k
10k
Gain Adjust
270k
180k
Logic 0
All Bits
to 10k
Rotates the Line
Gain Adjust
Range of
Gain Adjust
Range of
Gain Adjust
All Bits
Logic 0
7
Offset Adjustment
For unipolar (CSB) configurations, apply the digital input
code that should produce zero potential output and adjust the
Offset potentiometer for zero output.
For bipolar (COB, CTC) configurations, apply the digital
input code that should produce the maximum negative
output. Example: If the Full Scale Range is connected for
20V, the maximum negative output voltage is –10V. See
Table II for corresponding codes.
Gain Adjustment
For either unipolar or bipolar configurations, apply the
digital input that should give the maximum positive output.
Adjust the Gain potentiometer for this positive full scale
output. See Table II for positive full scale voltages and
currents.
TABLE II. Digital Input/Analog Output.
VOLTAGE OUTPUT MODELS
Output Range Connections
Internal scaling resistors provided in the DAC80 may be
connected to produce bipolar output voltage ranges of 10V,
+5V or 0 to +10V. See Figure 6.
FIGURE 6. Output Amplifier Voltage Range Scaling Circuit.
Gain and offset drift are minimized because of the thermal
tracking of the scaling resistors with other internal device
components. Connections for various output voltage ranges
are shown in Table III. Settling time for a full-scale range
change is specified as 4 s for the 20V range and 3 s for the
10V range.
DIGITAL INPUT
MSB
000000000000
011111111111
100000000000
111111111111
NOTE: (1) To obtain values for other binary ranges:
5V, or 2.5V; or unipolar output voltage ranges of 0 to
From Weighted
Resistor
Network
One LSB
Reference Input
LSB
0 to +5V range divide 0 to +10V range values by 2.
5V range: divide 10V range values by 2.
2.5V range: divide 10V range values by 4.
16
20
0 to +10V
+9.9976V
+5.0000V
+4.9976V
0.0000V
2.44mV
Summing
Junction
VOLTAGE
5k
NOTE: (1) Resistor Tolerances: ±2% max.
(1)
DAC80/80P
–10.0000V
+9.9951V
–0.0049V
0.0000V
ANALOG OUTPUT
4.88mV
18
(1)
6.3k
10V
To Reference Control Circuit
(1)
5k
(1)
–1.9995mA
–1.0000mA
–0.9995mA
0 to –2mA
0.0000mA
0.488 A
17
21
19
15
CURRENT
Bipolar
Offset
Common
Output
–0.9995mA
+0.0005mA
+1.000mA
0.0000mA
0.488 A
1mA
®