a
FEATURES
Single 8-Bit DAC
20-Pin SOIC/TSSOP Package
+2.7 V to +5.5 V Operation
Internal and External Reference Capability
DAC Power-Down Function
Parallel Interface
On-Chip Output Buffer Rail-to-Rail Operation
Low Power Operation 1.75 mA max @ 3.3 V
Power-Down to 1 A max @ 25؇C
APPLICATIONS
Portable Battery Powered Instruments
Digital Gain and Offset Adjustment
Programmable Voltage and Current Sources
Programmable Attenuators
+2.7 V to +5.5 V, Parallel Input,
Voltage Output 8-Bit DAC
AD7801
FUNCTIONAL BLOCK DIAGRAM
D7
D0
WR
CS
INPUT
REGISTER
DAC
REGISTER
I/V
MUX
CONTROL
LOGIC
I DAC
POWER-ON
RESET
÷2
AD7801
PD
CLR
LDAC
VOUT
REFIN
VDD
AGND
DGND
GENERAL DESCRIPTION
PRODUCT HIGHLIGHTS
The AD7801 is a single, 8-bit, voltage out DAC that operates
from a single +2.7 V to +5.5 V supply. Its on-chip precision output
buffer allows the DAC output to swing rail to rail. The AD7801
has a parallel microprocessor and DSP compatible interface with
high speed registers and double buffered interface logic. Data is
loaded to the input register on the rising edge of CS or WR.
1. Low Power, Single Supply operation. This part operates
from a single +2.7 V to +5.5 V supply and consumes typically
5 mW at 3 V, making it ideal for battery powered applications.
Reference selection for the AD7801 can be either an internal
reference derived from the VDD or an external reference applied
at the REFIN pin. The output of the DAC can be cleared by
using the asynchronous CLR input.
The low power consumption of this part makes it ideally suited
to portable battery operated equipment. The power consumption is less than 5 mW at 3.3 V, reducing to less than 3 µW in
power-down mode.
2. The on-chip output buffer amplifier allows the output of the
DAC to swing rail to rail with a settling time of typically 1.2 µs.
3. Internal or external reference capability.
4. High speed parallel interface.
5. Power-down capability. When powered down the DAC
consumes less than 1 µA at 25°C.
6. Packaged in 20-lead SOIC and TSSOP packages.
The AD7801 is available in a 20-lead SOIC and a 20-lead
TSSOP package.
REV. 0
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.
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Tel: 617/329-4700
World Wide Web Site: http://www.analog.com
Fax: 617/326-8703
© Analog Devices, Inc., 1997
