2
LC MOS
a
8-Bit DAC with Output Amplifiers
AD7224
FEATURES
FUNCTIO NAL BLO CK D IAGRAM
8-Bit CMOS DAC w ith Output Am plifiers
Operates w ith Single or Dual Supplies
Low Total Unadjusted Error:
Less Than 1 LSB Over Tem perature
Extended Tem perature Range Operation
P-Com patible w ith Double Buffered Inputs
Standard 18-Pin DIPs, and 20-Term inal Surface
Mount Package and SOIC Package
GENERAL D ESCRIP TIO N
P RO D UCT H IGH LIGH TS
T he AD7224 is a precision 8-bit voltage-output, digital-to-
analog converter, with output amplifier and double buffered
interface logic on a monolithic CMOS chip. No external trims
are required to achieve full specified performance for the part.
1. DAC and Amplifier on CMOS Chip
T he single-chip design of the 8-bit DAC and output amplifier
is inherently more reliable than multi-chip designs. CMOS
fabrication means low power consumption (35 mW typical
with single supply).
T he double buffered interface logic consists of two 8-bit regis-
ters–an input register and a DAC register. Only the data held in
the DAC registers determines the analog output of the con-
verter. T he double buffering allows simultaneous update in a
system containing multiple AD7224s. Both registers may be
made transparent under control of three external lines, CS, WR
and LDAC. With both registers transparent, the RESET line
functions like a zero override; a useful function for system cali-
bration cycles. All logic inputs are T T L and CMOS (5 V) level
compatible and the control logic is speed compatible with most
8-bit microprocessors.
2. Low T otal Unadjusted Error
T he fabrication of the AD7224 on Analog Devices Linear
Compatible CMOS (LC2MOS) process coupled with a novel
DAC switch-pair arrangement, enables an excellent total un-
adjusted error of less than 1 LSB over the full operating tem-
perature range.
3. Single or Dual Supply Operation
T he voltage-mode configuration of the AD7224 allows opera-
tion from a single power supply rail. T he part can also be op-
erated with dual supplies giving enhanced performance for
some parameters.
Specified performance is guaranteed for input reference voltages
from +2 V to +12.5 V when using dual supplies. T he part is also
specified for single supply operation using a reference of +10 V.
T he output amplifier is capable of developing +10 V across a
2 kΩ load.
4. Versatile Interface Logic
T he high speed logic allows direct interfacing to most micro-
processors. Additionally, the double buffered interface en-
ables simultaneous update of the AD7224 in multiple DAC
systems. T he part also features a zero override function.
T he AD7224 is fabricated in an all ion-implanted high speed
Linear Compatible CMOS (LC2MOS) process which has been
specifically developed to allow high speed digital logic circuits
and precision analog circuits to be integrated on the same chip.
REV. B
Inform ation furnished by Analog Devices is believed to be accurate and
reliable. However, no responsibility is assum ed by Analog Devices for its
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
otherwise under any patent or patent rights of Analog Devices.
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