DAC8560A BURR-BROWN [Burr-Brown Corporation], DAC8560A Datasheet - Page 18

• Manufacturer Part Number: DAC8560A
• Manufacturer: BURR-BROWN [Burr-Brown Corporation]

DAC8560
SLAS464 – DECEMBER 2006
18
DIGITAL-TO-ANALOG CONVERTER (DAC)
The DAC8560 architecture consists of a string DAC
followed by an output buffer amplifier.
shows a block diagram of the DAC architecture.
The input coding to the DAC8560 is straight binary,
so the ideal output voltage is given by:
where D
that is loaded to the DAC register; it can range from
0 to 65535.
RESISTOR STRING
The resistor string section is shown in
simply a string of resistors, each of value R. The
code loaded into the DAC register determines at
which node on the string the voltage is tapped off to
be fed into the output amplifier by closing one of the
switches connecting the string to the amplifier. It is
monotonic because it is a string of resistors.
OUTPUT AMPLIFIER
The output buffer amplifier is capable of generating
rail-to-rail voltages on its output, giving an output
range of 0V to V
2k
sink capabilities of the output amplifier can be seen
in the
1.8V/ s with a full-scale settling time of 8 s with the
output unloaded.
V
OUT
Register
in parallel with 1000pF to GND. The source and
DAC
+
65536
Typical
IN
Figure 62. DAC8560 Architecture
D
IN
= decimal equivalent of the binary code
62kW
DD
Characteristics. The slew rate is
Register String
V
REF
. It is capable of driving a load of
REF (+)
GND
V
REF ( ) -
REF
50kW
50kW
Figure
THEORY OF OPERATION
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Figure 62
63. It is
V
V
FB
OUT
The inverting input of the output amplifier is available
at the V
critical applications by tying the V
amplifier output together directly at the load. Other
signal conditioning circuitry may also be connected
between these points for specific applications.
V
FB
REF
2
V
pin. This feature allows better accuracy in
REF
Figure 63. Resistor String
R
R
R
R
R
DIVIDER
To Output Amplifier
(2x Gain)
FB
point and the
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