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ADV3205 Questions:  1) Datasheet typo? 2) What is the minimal setup?

Thread Summary

The user asked for clarification on the data clocking sequence in serial mode for the ADV3205 16x16 analog crosspoint switch and how to set up a minimal test for output resistance (Ron) between IN0 and OUT15. The support engineer confirmed that the data clocking sequence starts with OUT15_D4 and explained that Ron is not applicable for the ADV3205 due to its buffered switch design. The user found the comments useful.
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Hello

I have two questions about the ADV3205 16x16 analog crosspoint switch.

1) I would like a clarification about how data is clocked using the serial mode. If I well understood, in serial mode we need to clock 80 data inputs (LOW or HIGH), which correspond to 16 output pins x 5 bits (D4 down to D0) representing the input pin number (D3 to D0) and the pin state (D4). So, in other words we need to clock the data as this:

OUT15_D4, OUT15_D3, OUT15_D2.... OUT15_D0 ...... all the way down to .......  OUT0_D4, OUT0_D3...OUT0_D0.

 However, if you take a look at the datasheet, at page 4 (Timing characteristics for serial mode) the first data in seems to be OUT7_D4. Is this simply a typo or do I understood incorrectly how data is clocked? Here the link to the datasheet: http://www.analog.com/media/en/technical-documentation/data-sheets/ADV3205.pdf 

2) I am testing several crosspoint switches to check the output resistance (Ron) between two pins. For devices such as the AD75019 it was quite easy to achieve a minimal setup for testing the resistance. However, I am struggling to get the ADV3205 to work. Is there a minimal setup to test the resistance say between the IN0 pin and the OUT15? For instance, do I have to connect all the AGND pins, or the AVCCxx/yy or the AVEExx/yy pins, or I can simply focus on the pins I want to test? In other words, say I only want to connect IN0 and OUT15, what is the minimal connection setup needed to test the Ron of these two pins? If you could share a schematic it would be fantastic. 

Thank you very much!

Andrea

  • Hi Andrea,

    Apologies for the late reply. For your first question, your understanding is correct. You can refer to Figure 6 which illustrates the digital control interface, and will see that the Output 15 is in the furthest therefore should be programmed first. Figure 2 is just an example to illustrate the timing sequence of the crosspoint and doesn't intend to display the programming sequence.

    For your second query, the ADV3205 and all of the analog video crosspoints are buffered switches and are different with the unbuffered crosspoints such as AD75019. So the parameter Ron (which is the resistance from the input to the output of the unbuffered switch) in this regard for the ADV3205, doesn't have any meaning for a buffered crosspoint.

    I hope this helps. Let me know if you have any questions or clarifications.

    Regards,
    Goz

  • Thank you! Your comments were very useful.

    Best,

    Andrea