TMDS250

The TMDS250 is a 2-port digital video interface (DVI) or high-definition multimedia interface (HDMI) switch that allows up to 2 DVI or HDMI ports to be switched to a single display terminal. Four TMDS channels, one hot plug detector, and a digital display control (DDC) interface are supported on each port. Each TMDS channel supports signaling rates up to 2.5 Gbps to allow 1080p resolution in 12-bit color depth.

The input port is enabled by configuring source selectors, TMDS250 and S2. When an input port is selected, the TMDS inputs are connected to the TMDS outputs through a 2-to-1 multiplexer, the MOSFET between the input DDC channel and the output DDC channel is turned on, and the HPD output follows the state of the HPD_SINK. The other input port is inactive with disconnected input terminations, disconnected TMDS inputs to the outputs,disconnected DDC inputs to the outputs, and the HPD outputs are low state. Check the source selection look up table for the details of port selections.

When TMDS250 is high and S2 is low, all input terminations are disconnected, TMDS inputs are high impedance with standard TMDS terminations, all internal MOSFETs are turned off to disable the DDC links, and all HPD outputs are connected to the HPD_SINK. This allows the initiation of the HDMI physical address discovery process.

Termination resistors (50-), pulled up to V_CC , are integrated at each TMDS receiver input. External terminations are not required. A precision resistor is connected externally from the VSADJ pin to ground for setting the differential output voltage to be compliant with the TMDS standard.