Triple 2:1 Video Multiplexer# Technical Documentation: LMH6572MQ High-Speed Video Multiplexer
Manufacturer : National Semiconductor (NS) / Texas Instruments
Component : LMH6572MQ (Quad 2:1 High-Speed Video Multiplexer)
Package : 16-Pin QSOP (MQ Package)
Revision : 1.0
Date : October 2023
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## 1. Application Scenarios
### 1.1 Typical Use Cases
The LMH6572MQ is a monolithic, quad 2:1 multiplexer designed specifically for high-speed video and broadband signal routing applications. Each of the four independent multiplexers can switch between two input channels at speeds suitable for video signals up to HD and early digital video standards .
Primary Functions:
* Video Source Selection : Switching between multiple video sources (e.g., two cameras, two graphics outputs) to feed a single display or capture device.
* Picture-in-Picture (PIP) Switching : Rapidly multiplexing between main and secondary video feeds for PIP generation in display controllers.
* Test Equipment Signal Routing : Routing high-speed analog signals in automated test equipment (ATE) and video signal generators.
* Broadband Signal Switching : Handling RF and intermediate frequency (IF) signals in communication systems up to its bandwidth limit.
### 1.2 Industry Applications
* Professional & Broadcast Video : Used in video production switchers, routing switchers, and master control equipment for SD/HD-SDI ancillary path switching or analog component video routing.
* Medical Imaging Systems : Switching between multiple ultrasound transducer inputs or video outputs from different imaging modules (e.g., X-ray, MRI monitor outputs).
* Security & Surveillance Systems : Multiplexing feeds from multiple security cameras for recording, display, or motion detection analysis on a single channel.
* Avionics & Military Displays : Ruggedized systems requiring reliable switching between redundant video sources for cockpit displays or mission systems.
* High-End Test & Measurement : Serving as a critical component in video signal analyzers and waveform monitors for input channel selection.
### 1.3 Practical Advantages and Limitations
Advantages:
* High Performance : Features a -3 dB bandwidth of 200 MHz and a fast channel switching time of 10 ns (typ.) , enabling seamless video switching without visible artifacts.
* Excellent Video Specifications : Low differential gain/phase errors ( 0.02% / 0.02° ), crucial for maintaining color fidelity in NTSC/PAL systems.
* High Channel Isolation : Typically > 80 dB at 5 MHz, minimizing crosstalk between adjacent channels in dense designs.
* Flexible Supply Range : Operates from ±2.5 V to ±6 V dual supplies or a single +5 V to +12 V supply, accommodating various system power architectures.
* Integrated Output Buffer : Each multiplexer includes a current-feedback output amplifier capable of driving 50 Ω or 75 Ω lines directly, simplifying output stage design.
Limitations:
* Bandwidth for Modern Video : While excellent for its era, the 200 MHz bandwidth may be a limiting factor for very high-resolution analog video (e.g., UXGA) or digital video interfaces with high pixel clocks (> 300 MHz).
* Power Dissipation : With a typical supply current of 10 mA per channel (40 mA total), power dissipation can reach 300 mW at high supply voltages, requiring thermal consideration in enclosed spaces.
* Single-Ended Operation : Designed for single-ended signals. For differential signal routing, two devices and external components are required, increasing board space and complexity.
* Obsolete Status (Note) : The LMH6572 is classified as NRND (Not Recommended for New
