CMOS Dual 8-Bit
Buffered Multiplying DAC
a
AD7628
FEATURES
FUNCTIO NAL BLO CK D IAGRAM
On-Chip Latches for Both DACs
+12 V to +15 V Operation
DACs Matched to 1%
Four Quadrant Multiplication
TTL/ CMOS Com patible from +12 V to +15 V
Latch Free (Protection Schottkys not Required)
APPLICATIONS
Disk Drives
Program m able Filters
X-Y Graphics
Gain/ Attenuation
GENERAL D ESCRIP TIO N
P RO D UCT H IGH LIGH TS
T he AD7628 is a monolithic dual 8-bit digital/analog converter
featuring excellent DAC-to-DAC matching. It is available in
small 0.3" wide 20-pin DIPs and in 20-terminal surface mount
packages.
1. DAC to DAC matching: since both of the AD7628 DACs
are fabricated at the same time on the same chip, precise
matching and tracking between DAC A and DAC B is inher-
ent. T he AD7628’s matched CMOS DACs make a whole
new range of applications circuits possible, particularly in the
audio, graphics and process control areas.
Separate on-chip latches are provided for each DAC to allow
easy microprocessor interface.
2. Small package size: combining the inputs to the on-chip
DAC latches into a common data bus and adding a DAC A/
DAC B select line has allowed the AD7628 to be packaged in
a small 20-pin 0.3" wide DIP, 20-pin SOIC, 20-terminal
PLCC and 20-terminal LCC.
Data is transferred into either of the two DAC data latches via a
common 8-bit T T L/CMOS compatible input port. Control in-
put DAC A/DAC B determines which DAC is to be loaded.
T he AD7628’s load cycle is similar to the write cycle of a ran-
dom access memory, and the device is bus compatible with most
8-bit microprocessors, including 6502, 6809, 8085, Z80.
3. T T L-Compatibility: All digital inputs are T T L-compatible
over a +12 V to +15 V power supply range.
T he device operates from a +12 V to +15 V power supply and is
T T L-compatible over this range. Power dissipation is a low
20 mW.
Both DACs offer excellent four quadrant multiplication charac-
teristics with a separate reference input and feedback resistor for
each DAC.
REV. A
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use, nor for any infringem ents of patents or other rights of third parties
which m ay result from its use. No license is granted by im plication or
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© Analog Devices, Inc., 1996