CMOS 80MHz Monolithic 256 x 24 Color Palette RAM-DACs

The ADV478 (ADV®) and ADV471 are pin compatible and software compatible RAM-DACs designed specifically for Personal System/2 compatible color graphics.

The ADV478 has a 256x24 color lookup table with triple 8-bit video D/A converters. It may be configured for either 6 bits or 8 bits per color operation. The ADV471 has a 256x18 color lookup table with triple 6-bit video D/A converters.

Options on both parts include a programmable pedestal (0 or 7.5 IRE) and use of external voltage or current reference.

Fifteen overlay registers provide for overlaying cursors, grids, menus, EGA emulation, etc. Also supported is a pixel read mask register and sync generation on all three channels.

The ADV478 and ADV471 generate RS-343A compatible video signals into a doubly terminated 75 Ohm load, and RS-170 compatible video signals into a singly terminated 75 Ohm load, without requiring external buffering. Differential and integral linearity errors are guaranteed to be a maximum of ±1 LSB for the ADV478 and ±1/4 LSB for the ADV471 over the full temperature range.