1. General Description

The LT8641SXE is a Transition Minimized Differential Signaling (TMDS) switch that enables the connection of multiple High-Definition Multimedia Interface (HDMI) source devices to high-definition television (HDTV). Based on the HDMI 1.4 specification, LT8641SXE is an advanced TMDS switch that delivers a cost-effective method for manufacturers to add additional HDMI ports to their HDTV. Multiple HDMI ports allow consumers to connect variety HDMI-enabled sources to their HDTV. It supports HDCP 1.4 specifications, and Audio Return Channel function.

The LT8641SXE is a four-to-one (4:1) switch ideally suited for use in the back panel of HDTV and A/V receivers, allowing consumers to connect multiple HDMI-enabled devices such as high-definition DVD players, set top boxes and game consoles. The LT8641SXE switch selects a single HDMI or Digital Visual Interface (DVI) signal from the four receiver ports and generates HDMI/DVI audio/video output, as well as DDC/HPD switching, in full compliance with the HDMI and DVI specifications. The LT8641SXE also acts as a HDMI receiver. It extracts the digital audio information from the HDMI packet, and recovers digital audio to I2S/SPDIF interface. So it can be applied to the multi-channel audio amplifier for best audio effect. This feature can enable an external HDMI switching box acts as a home entertainment box that can output up to 8-channel high quality audio signal for the best audio effect.

To improve the performance in the case of long distance transmission, pre-emphasized driver is integrated into the chip. This pre-distortion technique compensates the transmission loss. The chip provides a Clock Data Recovery (CDR) path to enhance the performance. This path uses Re-Sample and Re-Drive architecture which re-samples data at the receiver side and re-drive data at the transmitter side. It will not pass through noise from inputs to output and hence provides reliable transmission.

The chip also employs an advanced on-die-termination calibrating circuitry.  The input termination is able to be automatically adjusted.  The integrated HPD switch as well as DDC switch lower the cost of system manufacture, and simplify the routing on the system board.

2. Features

• HDMI output resolution support up to 4Kx2K@30Hz and 4Kx2K @60Hz YCbCr 4:2:0 format
• Compliant with HDMI1.4/2.0 and HDCP1.4
• HDMI input resolution support up to 4Kx2K@30Hz and 4Kx2K @60Hz YCbCr 4:2:0 format
• Support 8 channel I2S audio outputs or both 6-channel I2S and SPDIF
• Supports 3D format
• Supports CEC
• Supports one channel ARC function on HDMI link.

3.  Application Diagram

• Embedded TV Switch
• External HDMI Switch
• Digital Audio Amplifier
• Etc.