DAC667JP BURR-BROWN [Burr-Brown Corporation], DAC667JP Datasheet - Page 5

• Manufacturer Part Number: DAC667JP
• Description: Microprocessor-Compatible 12-BIT DIGITAL-TO-ANALOG CONVERTER
• Manufacturer: BURR-BROWN [Burr-Brown Corporation]

zero analog output and all ones (FFF
output 1LSB below full scale.
Input coding for bipolar analog outputs is bipolar offset
binary (BOB), where an input code of 000
full-scale output, an input of FFF
below positive full scale, and zero occurs for an input code
of 800
The DAC667 can be used with two’s complement coding if
a logic inverter is used ahead of the MSB input (DB11).
INTERNAL/EXTERNAL REFERENCE USE
DAC667 contains a +10V reference which is trimmed to
typically 0.2% and tested and guaranteed to 1%. V
must be connected to V
with a nominal value of 50 . A trim potentiometer with a
nominal value of 100 can be used to provide adjustment to
zero gain error. If an external 10.000V reference is used, it
may be necessary to increase the trim range slightly.
The reference output may be used to drive external loads,
sourcing up to 5mA. The load current should be constant,
otherwise the gain (and bipolar offset, if connected) of the
converter will vary.
It is possible to use references other than +10V. The recom-
mended range of reference voltage is from +8V to +11V,
which allows both 8.192V and 10.24V ranges to be used.
The DAC667 is optimized for fixed-reference applications.
If the reference voltage is expected to vary over a wide
range, a CMOS multiplying D/A is a better choice.
GAIN AND OFFSET ADJUSTMENTS
Figures 2 and 3 illustrate the relationship of offset and gain
adjustments to a unipolar- and a bipolar-connected DAC667.
Offset should be adjusted first to avoid interaction of adjust-
ments.
FIGURE 2. Relationship of Offset and Gain Adjustments for
Range of
Offset Adj.
Offset Adjust Translates the Line
±0.4%
1LSB
HEX
.
a Unipolar D/A Converter.
All Bits
Logic 0
+ Full Scale
REF IN
Digital Input
through a gain adjust resistor
HEX
gives an output 1LSB
Rotates the Line
HEX
Gain Adjust
) gives an analog
HEX
Logic 1
All Bits
gives a minus
Range of
Gain Adj.
REF OUT
±1%
5
FIGURE 3. Relationship of Offset and Gain Adjustments for
Offset Adjustment
For unipolar (USB) operation, apply the digital input code
that should produce zero voltage output and adjust the offset
potentiometer for zero output. For bipolar (BOB, BTC)
operation, apply the digital input code that produces the
maximum negative output voltage and adjust the offset
potentiometer for minus full scale voltage. See Table II for
calibration values and codes.
Gain Adjustment
For either unipolar or bipolar operation, apply the digital
input that gives the maximum positive voltage output. Ad-
just the gain potentiometer for this positive full scale volt-
age. See Table II for calibration values.
SETTLING TIME
PERFORMANCE
The switches, reference and output amplifier of the DAC667
are designed for optimum settling time performance (Figure
4). Figure 4a shows the full scale range step response, V
–10V to +10V to –10V, for data input 000
000
full scale (+10V) for an output transition from –10V to
+10V. Figure 4c shows the settling time response at minus
TABLE II. Calibration Values.
Offset Adj.
Translates
DIGITAL
INPUT
FFF
800
7FF
000
1LSB
Offset Adjust
the Line
HEX
HEX
HEX
±0.4%
HEX
HEX
Range of
. Figure 4b shows the settling time response at plus
Logic 0
All Bits
+4.9987V
+2.5000V
+2.4987V
0 to +5V
0.0000V
+ Full Scale
1.22mV
a Bipolar D/A Converter.
Bipolar
Offset
0 to +10V
+9.9976V
+5.0000V
+4.9976V
0.0000V
2.44mV
Full Scale
1LSB
Range
Digital Input
ANALOG OUTPUT
+2.4987V
–0.0013V
–2.5000V
0.0000V
1.22mV
DAC667
2.5V
MSB on All
Others Off
+4.9976V
–0.0024V
–5.0000V
0.0000V
2.44mV
– Full Scale
Gain Adjust
Rotates the Line
HEX
5V
to FFF
Logic 1
All Bits
–10.0000V
+9.9951V
–0.0049V
Range of
Gain Adj.
0.0000V
4.88mV
10V
HEX
±1%
OUT
to
®