AD8170/AD8174 Output Capacitance

Hi

I am seraching for a an analog multiplexer with a very low "total" input capacitance value.

Output capacitance information exist only for AD8174 /"Output Capacitance Disabled (AD8174) 7.5 pF" page 3 of datasheet) when disable so could I assume that is 0 pF otherwise (It seems strange to me) 

There is no capacitance between input and output or betwwen inputs?

Capacitance from Source to Gnd, CsOff = ?

Capacitance from Drain to Gnd,CdOff = ?

Capacitance for on channel, Cs,Cd on = ?

Best Regards and thanks for your time

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  • +1
    •  Analog Employees 
    on Sep 25, 2019 2:57 AM

    Hi,

    AD8170/AD8174 has different architecture with most of the multiplexers. CsOff, CdOff and CdOn are not part of the specifications in the datasheet. These parts are buffered multiplexers, we can treat the channels as individual op amps in buffer config so what is given on the datasheet is only the input capacitance. The output capacitance is nearly zero or negligible on enabled state.

    The capacitance you will mostly be seeing will be due to stray capacitance on your PCB.


    Regards,
    Goz

Reply
  • +1
    •  Analog Employees 
    on Sep 25, 2019 2:57 AM

    Hi,

    AD8170/AD8174 has different architecture with most of the multiplexers. CsOff, CdOff and CdOn are not part of the specifications in the datasheet. These parts are buffered multiplexers, we can treat the channels as individual op amps in buffer config so what is given on the datasheet is only the input capacitance. The output capacitance is nearly zero or negligible on enabled state.

    The capacitance you will mostly be seeing will be due to stray capacitance on your PCB.


    Regards,
    Goz

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