National Semiconductor PowerWise LMH0394 SDI cable equaliser

The PowerWise LMH0394 serial digital interface cable equaliser from National Semiconductor is claimed to extend the reach of broadcast video signals by 40% (200 m at 3 Gbps) while delivering half the power (115 mW typical) of other equalisers.

The emergence of 3D TV, which requires stereoscopic video to be captured with two independent cameras, is forcing broadcasters to migrate to higher data rates (up to 3 Gbps) to transport high-definition video signals between equipment.

The increased data rates present signal integrity and power budget challenges at greater distances. The device provides what is believed to be the industry’s longest reach across all supported data rates - 200 m at 3 Gbps, 220 m at HD and 400 m at standard definition - and the lowest power consumption.

The equaliser provides the lowest output jitter across the entire range of cable lengths, enabling designers to meet system jitter budgets. The typical jitter is less than 0.15 unit intervals of output jitter up to 100 m, 0.20 UI up to 140 m and 0.40 UI up to 180 m at 3G data rates. The low output jitter also removes the need for input relocking of short-reach links, further saving power consumption.

Other features include power-efficient, low-voltage differential signalling drivers with programmable offset, amplitude and output de-emphasis, a cable length indicator that can approximate cable lengths within 1 m of accuracy, and support for passive external splitters. These features can be accessed through the device’s SPI programming interface.

A dual output version (the LMH0395) is also available, consuming 145 mW from a 2.5 V supply.