Using the AD75019 for audio.

Hello All,

I would like to design a footswitch for guitar effects based on the AD75019 component.

In the datasheet I saw that this 16x16 matrix does not include a buffer and that the average Ron is 150ohms with +/- 12V power supply.

Does the choice of this product for this type of application seem the most judicious to you?

If not, which product is the closest to the best solution?

Thanks for your feedback.

Vincent.

  • 0
    •  Analog Employees 
    on Sep 21, 2020 12:00 PM 2 months ago

    Hi Vincent, 

    I checked and we did see the part used in a similar application in the past.  That said how successful a fit the part will be will depends on a lot of your use case parameters.  For audio applications things like linearity (THD) and Ron would be important.  How much current will you need to pass through the switch?  THD+N here is 0.01%, which is -80dB, is this ok for you?  Do you need 16x16 channels?  If so this is the only part we have with that number of channels. There are some newer lower channel number models available.  ADI have "buffered" cross point switches you could consider if you need some gain, these are more targeted at video signal applications.  

    Regards,
    Eric.

  • Hello Eric and thank you for your quick response.
    Ideally, the signals carried by the matrix will be in the order of -10dBu, a guitar effect pedal at an input impedance of 1Mohm and 10Kohm or more at the output. So with relatively low currents. For the moment my diagram uses an 11x12 matrix (6 mono channels and 2 stereo channels, one Mono input and two Stereo outputs). The use of a circuit with buffers does not suit me because I seek as much as possible to have a direct path as pure as possible (the thrue-bypass is not possible using matrix).

    Regards.

    Vincent.

  • 0
    •  Analog Employees 
    on Sep 27, 2020 11:30 PM 2 months ago in reply to vidalv

    Hi Vincent,

    Apologies for the delay in replying. I think this switch could be a good option for you. You need a high number of channels and this part has the capacity. Since its high impedance current shouldn't be an issue. It will be worth your consideration. 

    Regards

    Eric. 

  • Hi Eric, no problem and thank you,

    I ordered a part for testing and will receive it in a few days.

    I have another question on the product feeds.

    Except the Ron which increases when the voltages of VDD and VSS are lowered, since I am going to pass signals of low amplitude will this have an impact on the quality of the signal, in other words, if instead of 3 power supplies, + 5V, + 12V and -12V I only put 2 power supplies, + 5V and -5V can the product work?

    Thank you for your support.

    Vincent.

  • 0
    •  Analog Employees 
    on Sep 29, 2020 6:45 PM 2 months ago in reply to vidalv

    Hi Vincent,

    You are correct, a lower bias voltage is going to increase the Ron. It will also change the matching/flatness versus Vs through the switch.  You can see example Ron plots with different supplies in our other newer switch datasheets, e.g. ADG5212, Figure5.  This part is an much older vintage and the datasheet doesn't have Ron plots but the spec table calls out 300ohms Ron with a +/-5V supply bias and a max of 500ohms. 

    The power supply will be able to work with a +/-5V bias.  The Min Vdd-Vss is 9V on the datasheet which would give you 10% margin on a +/-5V supply, so that is workable. 

    Eric.