AnsweredAssumed Answered

Video switch - which chip to use?

Question asked by shaurz on Feb 10, 2012
Latest reply on May 24, 2012 by theresaC

Please excuse my very basic/non-existent electronics knowledge.

 

I am trying to build an audio/video switch which supports analogue RGBHV video up to 480p/60 (640x480) resolution, to switch a possibly large number of input devices (maybe up to 10). This is a one-off project, so I am looking for through-hole components that I can easily put together with stripboard.

 

From browsing through lots of components I found the ADG451 which the datasheet lists audio/video switching as an application. Is this chip suitable for my requirements? Is it overkill? I noticed there are also lower-specced versions (ADG43x, ADG41x). I would rather pay for more expensive chips since I want very little quality degradation, no noticeable noise or ghosting.

 

Also I need to confirm if I've got the right idea about how this would work. So from what I understand, say I have a signal input (e.g. red colour channel) from N different devices, each connected to a source terminal on N separate ADG4xx chips. The sink terminals would all be connected to the same output line, and one of the chips would be selected, say by a rotary switch, which would select the right input to connect to the output. I've heard this is called a "bus switch". Would this work with the ADG4xx chips or have I got completely the wrong idea about what these things do?

 

Also I'm a little bit confused about how to connect up Vss, Vdd, VL. My best guess is that Vss is connected to GND and Vdd and VL are both connected to +5V. I will be using a single 5V power supply.

 

One last question. I want to use a rotary switch to select the input. I think I would need the ADG452 variant since I want it to switch on when the input is high (the switch would connect +5V to the input switch, and disconnect it when not selected). Am I right?

 

Thanks

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