SDI Input/Output Combined into single BNC Connection with Return Loss Network

National Semiconductor introduces the broadcast industry’s first configurable I/O chip for serial digital interface (SDI) broadcast video equipment.

By Cliff Roth

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Video/Imaging DesignWire
(4/19/2010 2:55:05 PM)

At the sprawling NAB broadcasters’ convention in Las Vegas last week, National Semiconductor sent word they’ve introduced what they say is the broadcast industry’s first configurable I/O chip for serial digital interface (SDI) broadcast video equipment. It simplifies design by providing manufacturers the flexibility to program their BNC interface connectors as either inputs (equalizer) or outputs (cable driver). The PowerWise® LMH0387 targets 3G/HD/SD video capture and editing cards that have a limited number of coax BNC connectors, as well as processing and distribution equipment that support a wide variety of I/O configurations.

Prior to the LMH0387’s availability, SDI ports were fixed as inputs or outputs, requiring designers to build one card per I/O configuration. Equipment manufacturers had to bear the higher research and development and inventory holding costs of supporting multiple configurations. By providing a flexible I/O BNC interface, the LMH0387 reduces the number of unique I/O configurations and associated costs. In addition, the universal BNC interface allows manufacturers to program their equipment I/O configurations post-delivery during studio installation. For example, a compact router frame with 64 BNCs may be configured as a 32 by 32 matrix, a 1 to 63 distribution amplifier, or any other combination of inputs and outputs to meet the application’s particular demand.

The LMH0387 is also the first solution to integrate the complex return loss network, to assure compliance to the Society of Motion Picture and Television Engineers (SMPTE) 424M return loss specification. The on-chip return loss network eliminates the time consuming and costly process of tweaking passive component values to achieve spec compliance. By integrating the network, the LMH0387 accelerates time-to-market, conserves board area, reduces bill of materials cost, and achieves greater than 5 dB of margin above the SMPTE specification.

The LMH0387 uses the same I/O pin for both input and output functions, and operates over a wide range of data rates from 125 Mbps to 2.97 Gbps, supporting SMPTE 424M, SMPTE 292M, SMPTE 344M and SMPTE 259M specifications. The LMH0387 equalizes up to 120 meters of Belden 1694A coaxial cable at 3G rates, 200 meters at high-definition (HD) rates and 400 meters at standard-definition (SD) rates. The LMH0387 delivers 75 ps rise and fall time performance and power-down control in the output driver mode. In the input mode, the device offers a power-saving sleep mode, programmable output common-mode voltage and swing, cable length indication, launch amplitude optimization, input signal detection and an SPI-compatible serial interface.

Available now, the LMH0387 is supplied in a 48-pin chip-scale package and is priced at $12.95 each in 1,000-unit quantities.