DAC7742 Datasheet, PDF (11/19 Pages) Burr-Brown (TI) – 16-Bit, Single Channel DIGITAL-TO-ANALOG CONVERTER With Internal Reference and Parallel Interface

THEORY OF OPERATION
The DAC7742 is a voltage output, 16-bit DAC with a +10V built-
in internal reference. The architecture is an R-2R ladder con-
figuration with the three MSBs segmented, followed by an
operational amplifier that serves as a buffer, as shown in Figure
1. The output buffer is designed to allow user-configurable
output adjustments giving the DAC7742 output voltage ranges
of 0V to +10V, –5V to +5V, or –10V to +10V. Please refer to
Figures 2, 3, and 4 for pin configuration information.
The digital input is a parallel word made up of the 16-bit DAC
code and is loaded into the DAC register using the LDAC
input pin. The converter can be powered from ±12V to ±15V
dual analog supplies and a +5V logic supply. The device
offers a reset function, which immediately sets the DAC
output voltage and DAC register to min-scale (code FFFF_H)
or mid-scale (code 7FFF_H). The data I/O and reset functions
are discussed in more detail in the following sections.
REF_ADJ REF_OUT REF_IN
V_REF
Buffer
R/4
+10V Internal
Reference
R
R/2 R/2 R/4
2R 2R
2R
2R
2R
2R
2R
2R
2R
R/4
FIGURE 1. DAC7742 Architecture.
V_REF
AGND
R_OFFSET
RFB2
RFB1
SJ
V_OUT
V_DD
0.1µF
1µF
Control Bus
DGND
V_DD
RST
LDAC
CS
R/W
RSTSEL
REFEN
REF_OUT
REFADJ
REF_IN
NC
V_SS
0.1µF
1µF
V_CC
0.1µF
1µF
Data Bus
DAC7742
NC
NC
DB6
DB5
DB4
DB3
Data Bus
DB2
DB1
DB0
NC
NC
NC
(0V to +10V)
FIGURE 2. Basic Operation: V_OUT = 0V to +10V.
DAC7742
11
SBAS256
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