DAC8043A
reference, the DAC output will provide a proportional dc voltage
output according to the transfer equation:
VOUT = –D/4096 × VREF
where D is the decimal data loaded into the DAC register and
VREF is the externally applied reference voltage source.
VREF
؎10VP VAC
VDD
R
2R 2R
RFB RFB
10pF
IOUT
GND
OP77
VOUT
DIGITAL INPUTS OMITTED FOR CLARITY
Figure 19. Unipolar (2-Quadrant) Operation
BIPOLAR 4-QUADRANT MULTIPLYING
Figure 20 shows a suggested circuit to achieve 4-quadrant mul-
tiplying operation. The summing amplifier multiplies VOUT1 by
2, and offsets the output with the reference voltage so that a
midscale digital input code of 2048 places VOUT2 at zero volts.
The negative full-scale voltage will be VREF when the DAC is
loaded with all zeros. The positive full-scale output will be
–(VREF – 1 LSB) when the DAC is loaded with all ones. Thus
the digital coding is offset binary. The voltage output transfer
equation for various input data and reference (or signal) values
follows:
VOUT2 = (D/2048 – 1) × –VREF
where D is the decimal data loaded into the DAC register and
VREF is the externally applied reference voltage source.
Precision resistors will be necessary to avoid ratio errors. Other-
wise trimming will be required to achieve full accuracy specifica-
tions available from the DAC8043A device. See the various
Analog Devices Digital Potentiometer products for automated
trimming solutions (e.g., the AD5204 for low voltage applica-
tions or the AD7376 for high voltage applications).
VDD
20k⍀
VREF
R
RFB
VAC
؎10VP
2R
2R RFB
10pF
IOUT
10k⍀
OP213
VOUT1
GND
DIGITAL INPUTS OMITTED FOR CLARITY (0V TO –VREF)
20k⍀
OP213
Figure 20. Bipolar (4-Quadrant) Operation
VOUT2
OUTLINE DIMENSIONS
8-Lead Plastic Dual In-Line Package [PDIP]
8-Lead Standard Small Outline Package [SOIC_N]
(N-8)
(R-8)
Dimensions shown in inches and (millimeters).
S-Suffix
Dimensions shown in millimeters and (inches).
8-Lead Thin Shrink Small Outline Package [TSSOP]
(RU-8)
Dimensions shown in millimeters.
–8–
REV. B