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Tel: 617/329-4700 Fax: 617/326-8703
FUNCTIONAL BLOCK DIAGRAM
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.
+5 Volt, Serial Input,
Dual 12-Bit DAC
12
CS
CLK
SDI
(DATA)
SDO
12
12
LDA
LDB
DGND
MSB
RS
AGND
D
REF
BUF
BANDGAP
REFERENCE
OP
AMP
A
DAC A
OP
AMP
B
AD8522
DAC A
REGISTER
D
DAC B
REGISTER
V
DD
V
OUTA
V
REF
V
OUTB
CONTROL
LOGIC
CLK
LATCH
REF
BUF
DAC B
SHIFT
REGISTER
inputs. A serial data output allows the user to easily daisy-chain
multiple devices in conjunction with a chip select input. A reset
RS input sets the outputs to zero scale or midscale, as deter-
mined by the input MSB.
The output 4.095 V full scale is laser trimmed to maintain accu-
racy over the operating temperature range of the device, and
gives the user an easy-to-use one-millivolt-per-bit resolution. A
2.5 V reference output is also available externally for other data
acquisition circuitry, and for ratiometric applications. The out-
put buffers are capable of driving ±5 mA.
The AD8522 is available in the 14-pin plastic DIP and low pro-
file 1.5 mm SOIC-14 packages.
GENERAL DESCRIPTION
The AD8522 is a complete dual 12-bit, single-supply, voltage
output DAC in a 14-pin DIP, or SO-14 surface mount package.
Fabricated in a CBCMOS process, features include a serial digi-
tal interface, onboard reference, and buffered voltage output.
Ideal for +5 V-only systems, this monolithic device offers low
cost and ease of use, and requires no external components to
realize the full performance of the device.
The serial digital interface allows interfacing directly to numer-
ous microcontroller ports, with a simple high speed, three-wire
data, clock, and load strobe format. The 16-bit serial word con-
tains the 12-bit data word and DAC select address, which is de-
coded internally or can be decoded externally using
LDA, LDB
0.6
0.4
0.2
0
–1.0
–0.6
–0.8
–0.2
–0.4
40960 30721024 2048
DIGITAL INPUT CODE – Decimal
LINEARITY ERROR – LSB
V
DD
= +4.5V
T
A
= –55°C, +25°C, +85°C, +125°C
+85°C
+125°C
+25°C
–55°C
PACKAGE TYPES AVAILABLE
AD8522
a
FEATURES
Complete Dual 12-Bit DAC
No External Components
+5 V Single-Supply Operation 610%
4.095 V Full Scale (1 mV/LSB)
Buffered Voltage Outputs
Low Power: 5 mW/DAC
Space Saving 1.5 mm Height SO-14 Package
APPLICATIONS
Digitally Controlled Calibration
Servo Controls
Process Control Equipment
Computer Peripherals
Portable Instrumentation
Cellular Base Stations Voltage Adjustment
Figure 1. Linearity Error vs. Digital Code & Temperature
