+2.7 V to +5.5 V, Parallel Input,
Voltage Output 8-Bit DAC
a
AD7801
FUNCTIO NAL BLO CK D IAGRAM
FEATURES
Single 8-Bit DAC
20-Pin SOIC/ TSSOP Package
+2.7 V to +5.5 V Operation
Internal and External Reference Capability
DAC Pow er-Dow n Function
Parallel Interface
On-Chip Output Buffer Rail-to-Rail Operation
Low Pow er Operation 1.75 m A m ax @ 3.3 V
Pow er-Dow n to 1 A m ax @ 25؇C
D7
INPUT
REGISTER
DAC
REGISTER
V
I DAC
MUX
I/V
OUT
D0
POWER-ON
RESET
WR
CS
CONTROL
LOGIC
÷2
AGND
AD7801
REFIN
V
DGND
PD
CLR
LDAC
DD
APPLICATIONS
Portable Battery Pow ered Instrum ents
Digital Gain and Offset Adjustm ent
Program m able Voltage and Current Sources
Program m able Attenuators
GENERAL D ESCRIP TIO N
P RO D UCT H IGH LIGH TS
1. Low Power, Single Supply operation. T his 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.
T he 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. T he 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.
2. T he 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.
Reference selection for the AD7801 can be either an internal
reference derived from the VDD or an external reference applied
at the REFIN pin. T he output of the DAC can be cleared by
using the asynchronous CLR input.
5. Power-down capability. When powered down the DAC
consumes less than 1 µA at 25°C.
6. Packaged in 20-lead SOIC and T SSOP packages.
T he low power consumption of this part makes it ideally suited
to portable battery operated equipment. T he power consump-
tion is less than 5 mW at 3.3 V, reducing to less than 3 µW in
power-down mode.
T he AD7801 is available in a 20-lead SOIC and a 20-lead
T SSOP package.
REV. 0
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which m ay result from its use. No license is granted by im plication or
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© Analog Devices, Inc., 1997