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TS5A3166: Flicker Noise

Hans
Genius 12705 points
Part Number: TS5A3166

Hello Team,

can you provide typical figure about noise spectrum density of analog switches (e.g. TS5A3166 would be of interest), please?

Especially flicker noise would be of interest.

Thanks and Best Regards,

Hans

  • 0
    TI__Mastermind 43295 points

    Hi Hans,

    We do not have this data for this device. I apologize for this - it isn't a spec that we typically characterize on our analog multiplexers.

    However the Johnson-Nyquist (thermal noise) can be approximated for the switch. This is because a switch is a pretty simple device and the other errors will come from specs like leakage current. 

    the noise voltage can be approximated as the following:

    where k_b is the Boltzman Constant (1.38 * 10^(-23)) J/K; T is the temperature in Kelvin; R is the Resistance of the switch, and delta f is the bandwidth of interest. If delta f is set as an independent variable you can get an approximated noise figure for the On resistance of interest. There is some complication due to Ron being variable (based on power supplies and input voltage) but using the Ron values in the spec tables can help give a range of possible thermal noise produced.

    Flicker noise is a bit trickier to calculate effectively for a switch - so unfortunately we don't have much information on this for this device.

    If you have any other questions please let me know!

    Best,

    Parker Dodson

     

  • 0 in reply to Parker Dodson
    TI__Genius 12705 points

    Hi Parker,

    if I assume the integral of the spectral density at low frequency (hence dominated by flicker) equal to the leakage current, do I make a too big mistake?

    In other words: is the flicker noise proportional to the leakage current (in this case 20nA x Rds,on) ?

    Thanks and Best Regards,

    Hans

  • 0 in reply to Hans
    TI__Intellectual 2694 points

    HI Parker,

    I am wondering if there is a way to separate the noise component of switch leakage from the inherent FET physics / schematic driven DC component. Definitely there is a direct relationship between the noise and I,R magnitude that can be leveraged to come up with close approximation.

    I understand this is a bit challenging for switches and something to check with the Design team using the precision portfolio (TMUX11xx/TMUX72xx) to model an approximate behavior for the TS5A3166.

    Thank you,


    Regards,

    Sandesh

  • 0 in reply to Hans
    TI__Mastermind 43295 points

    Hi Hans,

    I am sorry for the delay in responses - we are working with our design team to see if this is an okay approximation or if we have a better formula to approximate this. Due to this being a bit more complex issue and with current weather conditions in Dallas our answer time may be delayed, but I will keep you updated - but we may not have more information until next week.

    I will keep you updated as more information becomes available.

    Best,

    Parker Dodson

  • 0 in reply to Parker Dodson
    TI__Genius 12705 points

    Hi Parker,

    we understand! 

    Thanks and best Regards,

    Hans