DAC8501 Datasheet, PDF (11/18 Pages) Burr-Brown (TI) – Low-Power, Rail-to-Rail Output, 16-Bit Serial Input DIGITAL-TO-ANALOG CONVERTER

TYPICAL CHARACTERISTICS: V_DD = +2.7V (Cont.)
At T_A = +25°C, and +V_DD = +2.7V, unless otherwise noted.
CODE CHANGE GLITCH
Glitch Waveform (20mV/div)
Time (2µs/div)
THEORY OF OPERATION
DAC SECTION
The architecture consists of a string DAC followed by an
output buffer amplifier. Figure 1 shows a block diagram of the
DAC architecture.
RESISTOR STRING
The resistor string section is shown in Figure 2, it is 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
ensured monotonic because it is a string of resistors.
V_DD
V_FB
R
DAC Register
REF (+)
Resistor String
REF(–)
Output
V_OUT
Amplifier
R
GND
FIGURE 1. DAC8501 Architecture.
R
The input coding to the DAC8501 is straight binary, so the
ideal output voltage is given by:
V_OUT
=
V_REF
•
D
65536
(1)
where D = decimal equivalent of the binary code that is
loaded to the DAC register; it can range from 0 to 65535.
R
To Output
Amplifier
R
DAC8501
SBAS212A
FIGURE 2. Resistor String.
11
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