DVI/HDMI TMDS FR-4 and Cable Equalizer/Driver

The MAX3814 TMDS™ EQ/driver IC compensates for FR-4 and cable losses up to the DVI™/HDMI® transmit connector and provides a fully compliant DVI/HDMI TMDS output. The device can also be used in DVI/HDMI cable applications to extend reach and improve jitter margin of cable channels at the receive-side connector.

The on-chip TMDS drivers operate at a standard current level for implementing a typical DVI/HDMI nonback-terminated transmitter, as well as a 50% higher current mode for using a 200Ω back termination resistor (nonmatching) to achieve a 10dB return loss. Typical DVI/HDMI output drivers contribute to reflection problems between the connector and a typical high-impedance (open) DVI/HDMI Tx output. The selectable output current (LEVEL pin) gives the option of partial back termination (e.g., differentially connected 200Ω) to mitigate the reflection problem effectively while keeping common-mode offset to a minimum.

The 4-channel implementation treats all channels identically. To allow board layout flexibility for DVI and HDMI connectors, which have different channel order, the clock and data channels can be arbitrarily assigned.

The MAX3814 operates from a 3.3V power supply, standard for DVI/HDMI applications, and is packaged in a 5mm x 5mm x 0.1mm, 32-pin TQFP package.

Applications

* Cable TMDS Equalizer * Docking Station TMDS Equalizer and Driver * Laptop PC TMDS Equalizer and Driver

* Equalizes FR-4 Board Microstrip and Cable HF Losses Up to 15dB at 825MHz for Operation at 0.25Gbps to 1.65Gbps

* Compatible with HDMI 1.3

* Less Than 0.2UIP-P Residual Jitter at 1.65Gbps for 0 to 15dB Channel Loss at 825MHz

* Input Terminations: 50Ω (Each Side to VCC) ±10%

* Output of Driver is a Fully DVI/HDMI TMDS-Compatible Cable Driver

* Output Amplitude: 1.05VP-P Differential

* Enable Pin to Select Normal Operation or Power-Down Mode

* LEVEL Pin to Select Output Current for Use With or Without Back Termination

* 32-Pin TQFP for Four Channels; Any Channel Can Be Either a TMDS Data or Clock Signal

* VCC = 3.3V; Signal Pins Have Absolute Max Ratings of 5.5V (for Fault Conditions)