STMicroelectronics’ HDMIULC6 diode clamp network

Speaking of that ST part from the last post, here is a write-up I did about it a few months ago that I did not post. It is a little more formal since it was meant for print, but in a blog I can rave and point out that they are using SOI (silicon on insulator) technology, just like bleeding edge RF chips, in order to get that fabulously low stray capacitance of 0.6pF per pin.

Any designer that has taken a product through CE immunity testing knows how difficult it can be to protect cables from ESD. Protecting high-speed data cables is even more difficult since the protection needs to have extremely low capacitance so as not to affect the data stream and bit-error-rate. STMicroelectronics’ HDMIULC6 series is a diode clamp network that can work out to 5 Ghz. The new device allows a High Definition Multimedia Interface (HDMI), to operate at full HDMI speed of 1.65 Gbit/s and even up to 3.2 Gbit/s, with full 15kV contact and air Electrostatic Discharge (ESD) protection. ST has patents pending for technology architecture and design configuration.

The ultra-low line capacitance (0.6pF) of the HDMIULC6-4SC6 provides a new level of performance. For the first time, designers can protect these high-speed interfaces against 15kV air and contact discharges, above IEC 61000-4-2 level 4 standard, while minimizing distortion of the HDMI signal.

ST broke the 1pF barrier in line-capacitance without compromising the protection level by combining a rail-to-rail structure with a new process based on SOI (Silicon-on-Insulator) technology. This new process ensures that each protection element is highly isolated, being confined in an oxidized pocket. The resulting design noticeably reduces parasitic capacitance. In addition the 0.007pF matching of pin capacitance means there will be negligible skew created by the HDMIULC6.