ESD and Overcurrent Reference Layout for HDMI 1.3 Interfaces Based on Passive Protection Devices

The newest HDMI 1.3 standard doubles the previous HDMI data rate to 3.4Gbps per differential signal pair. With such high data transmission rates, low capacitance and good board design are crucial to provide adequate signal integrity.

Tyco Electronics’ new ESD and overcurrent protection reference layout for HDMI 1.3 was developed in conjunction with Efficere, Inc., a leader in high-speed interface design and test, and meets or exceeds the HDMI 1.3 specifications for operation at 3.4Gbps for Impedance (TDR), Data Eye, and Far End Crosstalk.

Achieving the optimum signal integrity and crosstalk performance with HDMI layouts is complicated, and adding ESD protection amplifies the design challenge, said Efficere Technologies Vice President of Sales, Joe O’Brien. Efficere has worked with Tyco Electronics to develop a layout with ESD protection that exceeds HDMI 1.3 requirements, and can help reduce electronic equipment manufacturers’ time to market.

The bi-directional PESD0603 or PESD0402 devices are configured in a very small space behind the HDMI connector and help designers meet the IEC 61000-4-2 standard for ESD protection (+/-15kV for air, +/-8kV for contact). The PESD devices are offered in EIA standard 0603 and 0402 sizes and can be used in various end applications, including DisplayPort, WiMAX and cellular base stations, eSATA, and other high-speed data and analog interfaces.

In HDMI source devices, such as DVD players, set-top boxes, computers and other HD sources, the specification requires that the transmitter interface’s voltage rail include overcurrent protection to prevent short circuit or abnormally high current from damaging the source device. Tyco Electronics’ protection layout includes optional overcurrent protection on the +5V rail, using the popular PolySwitch nanoSMD circuit protection device.