Datasheet
®
DAC811
6
±12V OPERATION
The DAC811 is fully specified for operation on ±12V power
supplies. However, in order for the output to swing to ±10V,
the power supplies must be ±13.5V or greater. When oper-
ating with ±12VB supplies, the output swing should be
restricted to ±8V in order to meet specifications.
LOGIC INPUT COMPATIBILITY
The DAC811 digital inputs are TTL, LSTTL, and 54/74HC
CMOS-compatible over the operating range of V
DD
. The
input switching threshold remains at the TLL threshold over
the supply range.
The logic input current over temperature is low enough to
permit driving the DAC811 directly from the outputs of
4000B and 54/74C CMOS devices.
Resistors of 47Ω should be placed in series with D0 through
D11, WR, N
A
, N
B
, N
C
and LDAC if edges are <10ns or if
the logic input is driven below ground by undershoot.
INSTALLATION
POWER SUPPLY CONNECTIONS
For optimum performance and noise rejection, power supply
decoupling capacitors should be added as shown in Figure 5.
These capacitors (1µF tantalum recommended) should be
located close to the DAC811.
FIGURE 3. Relationship of Offset and Gain Adjustments
for a Unipolar D/A Converter.
FIGURE 4. Relationship of Offset and Gain Adjustments
for a Bipolar D/A Converter.
TABLE III. Digital Input/Analog Output.
ANALOG OUTPUT
DIGITAL INPUT 0 to +10V
±5V ±10V
111111111111 +9.9976V +4.9976V +9.9951V
100000000000 +5V 0V 0V
011111111111 +4.9976V –0.0024V –0.0049V
000000000000 0V –5V –10V
LSB 2.4mV 2.44mV 4.88mV
MSB LSB
↓↓
GAIN ADJUSTMENT
For either unipolar or bipolar configurations, apply the
digital input that should give the maximum positive voltage
output. Adjust the gain potentiometer for this positive full
scale voltage. See Table III for positive full scale voltages.
FIGURE 5. Power Supply, Gain, and Offset Potentiometer
Connections.
+ Full Scale
All Bits
Logic 0
1LSB
Range of
Offset Adj.
Offset Adjust Translates the Line
Digital Input
All Bits
Logic 1
Range of
Gain Adjust
Analog Output
Gain Adjust
Rotates the Line
Full Scale Range
+ Full Scale
All Bits
Logic 0
1LSB
Range of
Offset Adjust
Digital Input
All Bits
Logic 1
Analog Output
Full Scale
Range
Gain Adjust
Rotates the Line
– Full Scale
MSB on All
Others Off
Bipolar V
Offset
Range of
Gain Adjust
Offset Adj.
Translates
the Line
≈ ±0.4%
1
2
3
4
5
6
7
8
9
10
11
12
13
14
28
27
26
25
24
23
22
21
20
19
18
17
16
15
10k to
100k
Ω
Ω
DD
V
BPO
V
DD
Summing
Junction
V
ACOM
Gain Adjust
DCOM
+V
CC
–V
CC
OUT
1µF
0.0022µF
1µF
3.9MΩ
1µF
–V
CC
+V
CC
+V
CC
10k to
100k
Ω
Ω
–V
CC
1MΩ
Connect for
Bipolar Operation