a
FEATURES
12-Bit CMOS DAC with Output Amplifier and
Reference
Improved AD7245/AD7248:
12 V to 15 V Operation
1/2 LSB Linearity Grade
Faster Interface–30 ns typ Data Setup Time
Extended Plastic Temperature Range (–40 C to +85 C)
Single or Dual Supply Operation
Low Power–65 mW typ in Single Supply
Parallel Loading Structure: AD7245A
(8+4) Loading Structure: AD7248A
LC MOS
12-Bit DACPORTs
AD7245A/AD7248A
AD7245A FUNCTIONAL BLOCK DIAGRAM
2
GENERAL DESCRIPTION
The AD7245A/AD7248A is an enhanced version of the industry
standard AD7245/AD7248. Improvements include operation
from 12 V to 15 V supplies, a
±
1/2 LSB linearity grade, faster
interface times and better full scale and reference variations with
V
DD
. Additional features include extended temperature range
operation for commercial and industrial grades.
The AD7245A/AD7248A is a complete, 12-bit, voltage output,
digital-to-analog converter with output amplifier and Zener volt-
age reference on a monolithic CMOS chip. No external user
trims are required to achieve full specified performance.
Both parts are microprocessor compatible, with high speed data
latches and double-buffered interface logic. The AD7245A ac-
cepts 12-bit parallel data which is loaded into the input latch on
the rising edge of
CS
or
WR.
The AD7248A has an 8-bit wide
data bus with data loaded to the input latch in two write opera-
tions. For both parts, an asynchronous
LDAC
signal transfers
data from the input latch to the DAC latch and updates the ana-
log output. The AD7245A also has a
CLR
signal on the DAC latch
which allows features such as power-on reset to be implemented.
The on-chip 5 V buried Zener diode provides a low noise, tem-
perature compensated reference for the DAC. For single supply
operation, two output ranges of 0 V to +5 V and 0 V to +10 V
are available, while these two ranges plus an additional
±
5 V
range are available with dual supplies. The output amplifiers are
capable of developing +10 V across a 2 kΩ load to GND.
The AD7245A/AD7248A is fabricated in linear compatible
CMOS (LC
2
MOS), an advanced, mixed technology process that
combines precision bipolar circuits with low power CMOS logic.
The AD7245A is available in a small, 0.3" wide, 24-pin DIP and
AD7248A FUNCTIONAL BLOCK DIAGRAM
SOIC and in 28-terminal surface mount packages. The
AD7248A is packaged in a small, 0.3" wide, 20-pin DIP and
SOIC and in 20-terminal surface mount packages.
PRODUCT HIGHLIGHTS
1. The AD7245A/AD7248A is a 12-bit DACPORT
®
on a single
chip. This single chip design and small package size offer
considerable space saving and increased reliability over
multichip designs.
2. The improved interface times on the part allows easy, direct
interfacing to most modern microprocessors.
3. The AD7245A/AD7248A features a wide power supply range
allowing operation from 12 V supplies.
DACPORT is a registered trademark of Analog Devices, Inc.
REV. A
Information furnished by Analog Devices is believed to be accurate and
reliable. However, no responsibility is assumed by Analog Devices for its
use, nor for any infringements of patents or other rights of third parties
which may result from its use. No license is granted by implication or
otherwise under any patent or patent rights of Analog Devices.
One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A.
Tel: 617/329-4700
Fax: 617/326-8703
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