National unveils LMH0384 cable equaliser

Edited by the Electronicstalk editorial team Apr 22, 2009

National Semiconductor has introduced a Powerwise 3Gbps serial digital interface (SDI) cable equaliser (EQ).

The energy-saving LMH0384 is claimed to simplify the design of broadcast video routers, production switchers, distribution amplifiers and editing and conversion equipment.

It offers low-output alignment jitter across cable lengths, allowing hardware designers more headroom for designing within system jitter budgets.

Tighter jitter budgets translate to cleaner system design, fewer bit errors and crisper images.

The LMH0384 guarantees less than 0.3 unit intervals (UIs) of output jitter from 0m to 110m of Belden 1,694A coaxial cable at 2.97Gbps.

It equalises up to 140m of cable at 3Gbps rates, 200m at high-definition (HD) rates and 400m at standard-definition (SD) rates.

The device adjusts equalisation levels based on cable length to receive incoming signals and provide low-jitter transmission of 1,080p HD broadcast video at up to 60 frames per second over a single coaxial cable.

The EQ supports two modes of operation: pin mode and register mode.

In pin mode, the EQ is fully backward compatible with National Instruments's other serial peripheral interface (SPI) equalisers.

Register mode opens up a suite of advanced features - accessible via an SPI bus - that enable flexibility to change and diagnose product parameters without requiring a board re-spin.

These include automatic power-down (auto-sleep), a cable length indicator, LVDS drivers with programmable offset and amplitude and a programmable input launch amplitude to facilitate operation with external splitters.

The LMH0384's 1.05V to 1.85V adjustable-output common-mode voltage eliminates the need for level-translation buffers by facilitating direct coupling to most field-programmable gate arrays (FPGAs) and signal-conditioning devices.

The EQ offers active sensing features to minimise power consumption and reduce cooling requirements in customer systems.

For example, in the event of cable detachment or loss of signal, the LMH0384 enters a power-saving auto-sleep mode to reduce power consumption by 85 per cent.

In active mode, the EQ automatically shifts equalisation stages at shorter cable lengths (less than 140m) to reduce power consumption by 20 per cent.

The EQ typically consumes 230mW of power from a single 3.3V supply.

The LMH0384 is a part of the company's broadcast video portfolio that enables Society of Motion Picture and Television Engineers (SMPTE) 424M, SMPTE 292M and SMPTE 259M uncompressed serial digital video routing and processing applications.

The LMH0384 also fully supports the digital video broadcasting-asynchronous serial interface (DVB-ASI) standard at 270Mbps for compressed video distribution in head-end equipment.

Offered in a 16-LLP package, the EQs are priced at USD21 (GBP14) each in 100-unit quantities.

The LMH0384 is sampling now, with production quantities scheduled for May 2009.

National Instruments's high-performance, energy-efficient analogue technology can help video engineers differentiate their products.

The company provides the key functions that every system engineer requires, including operational amplifiers, power management, data conversion, interface and serial digital video products, audio subsystems, display ICs and networking products.

National Instruments will demonstrate the LMH0384 at the NAB exhibition (Booth SU2804) in Las Vegas on 20-24 April.