01-12-2012, 02:08 PM
High Speed Video Multiplexer
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General Description
The LMH®6570 is a high performance analog multiplexer optimized
for professional grade video and other high fidelity
high bandwidth analog applications. The output amplifier selects
one of two buffered input signals based on the state of
the SEL pin. The LMH6570 provides a 400 MHz bandwidth at
2 VPP output signal levels. Multimedia and high definition television
(HDTV) applications can benefit from the LMH6570's
0.1 dB bandwidth of 150 MHz and its 2200 V/μs slew rate.
The LMH6570 supports composite video applications with its
0.02% and 0.05° differential gain and phase errors for NTSC
and PAL video signals while driving a single, back terminated
75Ω load. An 80 mA linear output current is available for driving
multiple video load applications.
The LMH6570 gain is set by external feedback and gain set
resistors for maximum flexibility.
Features
● 500 MHz, 500 mVPP, −3 dB bandwidth, AV=2
● 400 MHz, 2VPP, −3 dB bandwidth, AV=2
● 8 ns channel switching time
● 70 dB channel to channel isolation @ 10 MHz
● 0.02%, 0.05° diff. gain, diff. phase
● 0.1 dB gain flatness to 150 MHz
● 2200 V/μs slew rate
● Wide supply voltage range: 6V (±3V) to 12V (±6V)
● −68 dB HD2 @ 5 MHz
● −84 dB HD3 @ 5 MHz
Applications
● Video router
● Multi input video monitor
● Instrumentation / Test equipment
● Receiver IF diversity switch
● Multi channel A/D driver
● Picture in Picture video switch
VIDEO PERFORMANCE
The LMH6570 has been designed to provide excellent performance with production quality video signals in a wide variety of formats
such as HDTV and High Resolution VGA. Best performance will be obtained with back-terminated loads. The back termination
reduces reflections from the transmission line and effectively masks transmission line and other parasitic capacitances from the
amplifier output stage. Figure 1 shows a typical configuration for driving a 75Ω cable. The output buffer is configured for a gain of
2, so using back terminated loads will give a net gain of 1.