DAC8531 Datasheet, PDF (11/19 Pages) Texas Instruments – 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, 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
Figure 2 shows the resistor string section. 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
REF (+)
V_OUT
DAC Register
Resistor String
REF(–)
Output
Amplifier
R
GND
R
FIGURE 1. DAC8531 Architecture.
The input coding to the DAC8531 is straight binary, so the
ideal output voltage is given by:
V_OUT
=
V_REF
•
D
65536
R
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
DAC8531
SBAS192B
FIGURE 2. Resistor String.
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