The TVP3703 and TVP3409 are two new SVGA compatible, true-color CMOS RAMDACs. Both devices are highly integrated, featuring high-speed triple 8-bit DACs, three 256-by-8-color lookup tables, and a programmable pixel multiplexing interface. In addition to these high-end RAMDAC features, the devices also reduce component count, board space, and electrical emissions by integrating dual frequency synthesis PLLs, which are used to generate the controller's memory and video clocks at frequencies up to 80 MHz.
The TVP3703 and TVP3409 RAMDACs utilize a low cost DRAM frame buffer to reduce overall system cost. The 24-bit packed pixel mode allows maximum use of controller-to-RAMDAC bandwidth. This enables a much higher screen refresh rate in 800 x 600 x 24 mode and makes 1024 x 768 x 24 mode possible with a 3 MByte frame buffer.
The TVP3703 features a serializing 16-bit pixel port providing 170 MHz 8-bit and 73 MHz 24-bit packed pixel modes using an internal PLL. The 16-bit pixel port also provides faster high-color/true-color operation up to the 110 MHz pixel rate. The port can also be configured as an 8-bit pixel port giving standard SVGA and high-color/true-color modes up to 110 MHz. The video clock can be one of two VGA base frequencies or fourteen VESA standard frequencies which can also be programmed through the standard micro port interface. The TVP3703 is functionally interchangeable with STG1703.
The TVP3409 features a clock multiplier PLL that multiplies the controller PCLK to obtain the pixel clock at frequencies up to 170 MHz. The PLLs are used to generate the controller's memory and video clocks at frequencies up to 85 MHz. The TVP3409 also shares a common register format with the 8-bit ATT20C498/499, allowing software compatibility.
The TVP3703 and TVP3409 are compatible with most industry standard graphics controllers and are now available from Texas Instruments and TI authorized distributors in a 68-pin PLCC package.
TVP3703 data manual
TVP3409 data manual
Vol 17, June, 1996
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