SMPTE 292M/259M Digital Video Serializer w/ Video & Ancillary Data FIFOs & Integrated Cable Driver 64-TQFP 0 to 70# Technical Documentation: LMH0030VS Serial Digital Interface (SDI) Cable Driver
Manufacturer : National Semiconductor Corporation (NSC)
Component Type : High-Speed, 3.3V SDI Cable Driver
Document Revision : 1.0
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## 1. Application Scenarios
### 1.1 Typical Use Cases
The LMH0030VS is a monolithic, high-performance cable driver designed specifically for serial digital video applications according to SMPTE 259M, SMPTE 344M, and DVB-ASI standards. Its primary function is to transmit serial digital data over coaxial cables in broadcast and professional video environments.
Core Functions:
* Signal Re-clocking and Amplification: Accepts a serial digital data stream, re-clocks it with an internal PLL, and amplifies it to produce a compliant output signal for driving 75Ω coaxial cables.
* Cable Equalization Compensation: While primarily a driver, it is designed to work in tandem with equalizers (like the LMH0044) to compensate for cable losses, though its main role is transmission.
* Jitter Attenuation: The integrated Phase-Locked Loop (PLL) cleans incoming signals, reducing timing jitter, which is critical for maintaining signal integrity over long distances.
### 1.2 Industry Applications
* Broadcast Television: Core component in routing switchers, digital video recorders (DVR/SSD), master control switchers, and camera control units (CCU) for distributing SD-SDI (270 Mbps) and HD-SDI (1.485 Gbps) signals.
* Professional Video Production: Used in video servers, editing suites, graphics systems, and format converters for reliable signal distribution within a facility.
* Telecommunications: Employed in video contribution and distribution links that utilize the DVB-ASI standard for MPEG transport stream transmission.
* Medical Imaging: High-fidelity video transmission in surgical and diagnostic imaging systems requiring uncompressed digital video.
* Test & Measurement Equipment: A key component in signal generators, waveform monitors, and cable testers for generating reference SDI outputs.
### 1.3 Practical Advantages and Limitations
Advantages:
* High Performance: Supports data rates from 50 Mbps to 1.5 Gbps, covering SD-SDI, HD-SDI, and DVB-ASI standards.
* Low Power: Operates from a single 3.3V supply, typically consuming 180 mW, making it suitable for high-density board designs.
* Integrated PLL: Eliminates the need for an external reference clock, simplifying design and reducing component count. The PLL provides excellent jitter performance.
* Robust Output: Features a current-mode logic (CML) output stage with adjustable output amplitude, capable of driving long cables (100m+ of Belden 1694A equivalent at 1.485 Gbps when paired with an appropriate equalizer).
* Fail-Safe Design: Includes a loss-of-input (LOI) detection circuit that mutes the output to prevent noise transmission when the input signal is absent.
Limitations:
* Not an Equalizer: The LMH0030VS is a driver only. For receiving signals over long cables, a dedicated cable equalizer (e.g., LMH0044) is required on the receive side.
* Limited to 1.5 Gbps: Not suitable for 3 Gbps (SDI Level B) or higher data rates (e.g., 12G-SDI). For these, newer generation devices are necessary.
* Single Supply Voltage: Requires a clean, well-regulated 3.3V supply. It is not compatible with 5V systems without level translation.
* Heat Dissipation: While
