February 1995
MICRO-DACTM DAC1208/DAC1209/DAC1210/DAC1230/
DAC1231/DAC1232 12-Bit, mP Compatible,
Double-Buffered D to A Converters
General Description
Features
Y
Linearity specified with zero and full-scale adjust only
The DAC1208 and the DAC1230 series are 12-bit multiply-
ing D to A converters designed to interface directly with a
wide variety of microprocessors (8080, 8048, 8085, Z-80,
etc.). Double buffering input registers and associated con-
trol lines allow these DACs to appear as a two-byte ‘‘stack’’
in the system’s memory or I/O space with no additional in-
terfacing logic required.
Y
Direct interface to all popular microprocessors
Y
Double-buffered, single-buffered or flow through digital
data inputs
Y
Logic inputs which meet TTL voltage level specs (1.4V
logic threshold)
Y
g
Works with 10V referenceÐfull 4-quadrant
multiplication
The DAC1208 series provides all 12 input lines to allow sin-
gle buffering for maximum throughput when used with 16-bit
processors. These input lines can also be externally config-
ured to permit an 8-bit data interface. The DAC1230 series
can be used with an 8-bit data bus directly as it internally
formulates the 12-bit DAC data from its 8 input lines. All of
these DACs accept left-justified data from the processor.
Y
Y
Y
Operates stand-alone (without mP) if desired
All parts guaranteed 12-bit monotonic
DAC1230 series is pin compatible with the DAC0830
series 8-bit MICRO-DACs
The analog section is a precision silicon-chromium (Si-Cr)
R-2R ladder network and twelve CMOS current switches.
An inverted R-2R ladder structure is used with the binary
Key Specifications
Y
Current Settling Time
1 ms
Y
weighted currents switched between the I
OUT1
and I
OUT2
Resolution
12 Bits
maintaining a constant current in each ladder leg indepen-
dent of the switch state. Special circuitry provides TTL logic
input voltage level compatibility.
Y
Linearity (Guaranteed
over temperature)
10, 11, or 12 Bits of FS
Y
Gain Tempco
1.3 ppm/ C
§
20 mW
The DAC1208 series and DAC1230 series are the 12-bit
members of a family of microprocessor compatible DACs
(MICRO-DACsTM). For applications requiring other resolu-
tions, the DAC1000 series for 10-bit and DAC0830 series
for 8-bit are available alternatives.
Y
Low Power Dissipation
Y
Single Power Supply
5 V to 15 V
DC DC
Typical Application
TL/H/5690–1
TRI-STATEÉ is a registered trademark of National Semiconductor Corp.
MICRO-DACTM is a trademark of National Semiconductor Corp.
C
1995 National Semiconductor Corporation
TL/H/5690
RRD-B30M115/Printed in U. S. A.