VT1631 LVDS Transmitter

With the growth of devices such as digital satellite systems, HDTV, DVD players, camcorders and cameras, combined with applications like games, web content, PC graphics, etc., consumers are demanding higher quality methods to transfer video and images for electronic devices. While legacy solutions are still widely used, noise generation, power consumption, and noise immunity make them less than perfect solutions.

The VIA VT1631 is a Low Voltage Differential Signaling (LVDS) Transmitter that enables a vast improvement in the amount and quality of video data that can be transferred between devices enabling higher resolutions, lower power requirements, and universal connectivity.

Designed to support pixel data transmissions from a Host to a Flat Panel display ranging from VGA to UXGA resolutions, the VIA VT1631 complies with the Open LDI Specification for Digital Display Interfaces. Supporting data speeds up to 592Mbytes/sec on each LVDS line for a aggregate throughput rate of 4.76Gbps, the VIA VT1631 has a narrow bus to reduce cable size and cost, and comes in a TQFP-100 Thin Quad Flat package, making it ideal for applications such as connections to flat panel displays in notebook computers.

The VIA VT1631 is designed to be compatible with Graphics Memory Controller Hub by implementing two data cycles per clock, that can be controlled by a two-wire serial communication interface. Two input modes are supported: one port of 12-bit (two data cycles per clock) input data for 24-bit RGB, and two ports of 12-bit (two data cycles per clock) input for dual 24-bit RGB (48-bit in total). In both modes, input data will be clocked on both rising and falling edges in LVTTL level operation, or clocked on the cross over of differential clock signals in the low swing operation. Each input data width will be 1/2 of clock cycle.

With an input clock at 85MHz and input data at 170Mbps, the maximum transmission rate of each LVDS line is 592 Mbps, for an aggregate throughput rate of 2.38Gbps/4.76Gbps. It converts 24/48 bits (Single/Dual Pixel 24-bit color) of data into 4/8 LVDS data streams.

The VIA VT1631 is an ideal solution to solve EMI and cable size problems for high-resolution flat panel display applications. Providing a reliable industry standard interface based on LVDS technology, the VIA VT1631 delivers the bandwidth needed for high-resolution panels while maximizing bit times, and keeping clock rates low to reduce EMI and shielding requirements.

VT1631 Block Diagram


Features of VIA VT1631

» Complies with Open LDI Specification for Digital Display Interfaces
» 25 to 85 MHz Input Clock Support
» Supports VGA through UXGA Panel Resolution
» Power-down mode <198uW max (TBD)
» Two-wire Serial Communication Interface up to 400KHz
» Narrow Bus reduces cable size and cost
» Up to 4.76 Gbps bandwidth in dual 24-bit RGB into Dual Pixel Out applications
» Up to 592Mbytes/sec bandwidth
» Dual 12-bit double pumped digital input port
» PLL requires no external components
» Support both LVTTL and low voltage level input (Capable of 1.0 to 1.8V)
» Programmable input clock and control strobe select
» Compatible with TIA/EIA-644
» 2.24 to 2.75 supply voltage
» TQFP-100 Thin Quad Flat package

VIA Technologies, Inc.