12 Channel, 8-Bit TrimDACs
with Power Shutdown
Replaces 12 Potentiometers
Individually Programmable Outputs
3-Wire SPI Compatible Serial Input
Power Shutdown <55 Watts Including IDD & IREF
Midscale Preset, AD8802
Separate VREFL Range Setting, AD8804
+3 V to +5 V Single Supply Operation
Video and Audio Equipment Gain and Offset Adjustment
Portable and Battery Operated Equipment
The 12-channel AD8802/AD8804 provides independent digitally-
controllable voltage outputs in a compact 20-lead package. This
potentiometer divider TrimDAC® allows replacement of the
mechanical trimmer function in new designs. The AD8802/
AD8804 is ideal for dc voltage adjustment applications.
Easily programmed by serial interfaced microcontroller ports,
the AD8802 with its midscale preset is ideal for potentiometer
replacement where adjustments start at a nominal value. Appli-
cations such as gain control of video amplifiers, voltage con-
trolled frequencies and bandwidths in video equipment,
geometric correction and automatic adjustment in CRT com-
puter graphic displays are a few of the many applications ideally
suited for these parts. The AD8804 provides independent con-
trol of both the top and bottom end of the potentiometer divider
allowing a separate zero-scale voltage setting determined by the
VREFL pin. This is helpful for maximizing the resolution of
devices with a limited allowable voltage control range.
Internally the AD8802/AD8804 contains 12 voltage-output
digital-to-analog converters, sharing a common reference-
TrimDAC is a registered trademark of Analog Devices, Inc.
FUNCTIONAL BLOCK DIAGRAM
(AD8802 ONLY) (AD8804 ONLY)
Each DAC has its own DAC latch that holds its output state.
These DAC latches are updated from an internal serial-to-
parallel shift register that is loaded from a standard 3-wire
serial input digital interface. The serial-data-input word is
decoded where the first 4 bits determine the address of the DAC
latches to be loaded with the last 8 bits of data. The AD8802/
AD8804 consumes only 10 µA from 5 V power supplies. In ad-
dition, in shutdown mode reference input current consumption
is also reduced to 10 µA while saving the DAC latch settings for
use after return to normal operation.
The AD8802/AD8804 is available in the 20-pin plastic DIP, the
SOIC-20 surface mount package, and the 1 mm thin TSSOP-20
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.
© Analog Devices, Inc., 1995
One Technology Way, P.O. Box 9106, Norwood. MA 02062-9106, U.S.A.