AL875

Preliminary version subject to change without notice

January 25, 2001

5

3.0 General Description

The AL875 is a high-speed triple 8-bit monolithic analog-to-digital converter (ADC) designed for

digitizing RGB graphics/video signal or other applications. Its 110 MHz conversion rate can support

display resolution of up to 1280x1024 at 60Hz refresh rate.

The AL875 accepts 0.6~2.0V analog input range without using pre-amplifiers which may reduce the

overall S/N ratio. Digitized data is piped at the full clock rate to the 24-bit output port. The AL875

uses 3.3V power with 5V tolerant I/O and low power dissipation.

The sampling clock is provided by an external clock source, usually a PLL, which multiplies the

frequency of the input reference clock (usually a HSYNC signal) to generate the sampling clock. The

AL875 provides a programmable PLL divider up to 4096.

In addition, the input active horizontal and vertical starting and ending positions can be detected to

ensure that the whole picture fits into the displayable region of the screen. Through an I

the AL875 is fully programmable to support various graphic resolutions.