- 软件介绍
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. 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.
Internally the AD8802/AD8804 contains 12 voltage-output digital-to-analog converters, sharing a common reference-voltage input.
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 A from 5 V power supplies. In addition, in shutdown mode reference input current consumption is also reduced to 10 A 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.
