AD8802| Datasheet

AD8802, AD8804

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FEATURES Low Cost 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 APPLICATIONS Automatic Adjustment Trimmer Replacement Video and Audio Equipment Gain and Offset Adjustment Portable and Battery Operated Equipment

12 Channel, 8-Bit TrimDACs with Power Shutdown AD8802/AD8804
FUNCTIONAL BLOCK DIAGRAM
CS CLK
D7

AD8802/AD8804
DAC 1 DAC REG #1
D0 R

VDD VREFH O1 O2 O3 O4 O5 O6 O7 O8 O9 O10 O11 O12

D11 D10 D9 D8 D7

ADDR DEC

SER REG SDI
D D0 D7

DAC 12 DAC REG #12
R

8 D0

SHDN

GENERAL DESCRIPTION

The 12-channel AD8802/AD8804 provides independent digitallycontrollable 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. Applications such as gain control of video amplifiers, voltage controlled frequencies and bandwidths in video equipment, geometric correction and automatic adjustment in CRT computer graphic displays are a few of the many applications ideally suited for these parts. The AD8804 provides independent control 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. In
ternally the AD8802/AD8804 contains 12 voltage-output digital-to-analog converters, sharing a common referencevoltage input.
TrimDAC is a registered trademark of Analog Devices, Inc.

GND

RS (AD8802 ONLY)

VREFL (AD8804 ONLY)

Each DAC has its own DAC latch that holds its output state. These DAC latches are updated from an internal serial-toparallel 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 uA from 5 V power supplies. In addition, in shutdown mode reference input current consumption is also reduced to 10 uA 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 package.

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