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AD7226
LC
2
MOS
Quad 8-Bit D/A Converter
FUNCTIONAL BLOCK DIAGRAM
CONTROL
LOGIC
DAC A
DAC B
DAC C
DAC D
LATCH A
LATCH B
LATCH C
LATCH D
A
B
C
D
MSB
DATA
(8-BIT)
LSB
WR
A1
A0
V
SS
AGND AGND
V
REF
V
DD
V
OUT
A
V
OUT
B
V
OUT
C
V
OUT
D
D
A
T
A
B
U
S
AD7226
GENERAL DESCRIPTION
The AD7226 contains four 8-bit voltage-output digital-to-
analog converters, with output buffer amplifiers and interface
logic on a single monolithic chip. No external trims are required
to achieve full specified performance for the part.
Separate on-chip latches are provided for each of the four D/A
converters. Data is transferred into one of these data latches
through a common 8-bit TTL/CMOS (5 V) compatible input
port. Control inputs A0 and A1 determine which DAC is
loaded when WR goes low. The control logic is speed-compat-
ible with most 8-bit microprocessors.
Each D/A converter includes an output buffer amplifier capable
of driving up to 5 mA of output current. The amplifiers’ offsets
are laser-trimmed during manufacture, thereby eliminating any
requirement for offset nulling.
Specified performance is guaranteed for input reference voltages
from 2 V to 12.5 V with dual supplies. The part is also specified
for single supply operation at a reference of 10 V.
The AD7226 is fabricated in an all ion-implanted high speed
Linear Compatible CMOS (LC
2
MOS) process, which has been
specifically developed to allow high speed digital logic circuits
and precision analog circuits to be integrated on the same chip.
PRODUCT HIGHLIGHTS
1. DAC-to-DAC Matching
Since all four DACs are fabricated on the same chip at the
same time, precise matching and tracking between the DACs
is inherent.
2. Single-Supply Operation
The voltage mode configuration of the DACs allows the
AD7226 to be operated from a single power supply rail.
3. Microprocessor Compatibility
The AD7226 has a common 8-bit data bus with individual
DAC latches, providing a versatile control architecture for
simple interface to microprocessors. All latch enable signals
are level triggered.
4. Small Size
Combining four DACs and four op amps plus interface logic
into a 20-pin package allows a dramatic reduction in board
space requirements and offers increased reliability in systems
using multiple converters. Its pinout is aimed at optimizing
board layout with all the analog inputs and outputs at one
end of the package and all the digital inputs at the other.
FEATURES
Four 8-Bit DACs with Output Amplifiers
Skinny 20-Lead DIP, SOIC, SSOP, and PLCC Packages
Microprocessor-Compatible
TTL/CMOS-Compatible
No User Trims
Extended Temperature Range Operation
Single Supply Operation Possible
APPLICATIONS
Process Control
Automatic Test Equipment
Automatic Calibration of Large System Parameters,
e.g., Gain/Offset
