About specification of LF398S

Hi all,
I would like to ask about LF398S.

LF398S:Precision Sample and Hold Amplifier in SO8 Package
www.analog.com/.../lf398s.html

① How is the timing of sample and hold determined?
(For example, How long does it take to hold the voltage from the sample start timing?)

② Does the sampling and hold timing change with the input waveform (e.g. triangle wave)?

Thanks

Top Replies

    •  Analog Employees 
    Nov 25, 2018 +1 verified

    Hi Takahiro,

    If we look at
    LF398N datasheet which is the LF398 DIP8 package, we can see the aperture time specification on page 4 (9-100).
    Aperture time is defined as the time when the signal is disconnected…

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  • +1
    •  Analog Employees 
    on Nov 25, 2018 9:41 AM over 2 years ago

    Hi Takahiro,

    If we look at LF398N datasheet which is the LF398 DIP8 package, we can see the aperture time specification on page 4 (9-100).
    Aperture time is defined as the time when the signal is disconnected from the hold capacitor when the hold command is triggered.

    For the LF398, it's typically around 150ns for positive input step and typically around 200ns for negative input step at ambient temperature.



    This aperture time won't change with the input waveform, just make sure that the input's transition during the
    delay time won't affect the desired voltage on hold capacitor.

    Is this the timing you're referring to takahiro?
    You can learn more about Sample and Hold Amplifiers in this article:
    https://www.analog.com/media/cn/training-seminars/tutorials/mt-090.pdf

    If you have further clarification, feel free to ask.
    Thanks a lot Takahiro.

    Best Regards,
    Dann

Reply
  • +1
    •  Analog Employees 
    on Nov 25, 2018 9:41 AM over 2 years ago

    Hi Takahiro,

    If we look at LF398N datasheet which is the LF398 DIP8 package, we can see the aperture time specification on page 4 (9-100).
    Aperture time is defined as the time when the signal is disconnected from the hold capacitor when the hold command is triggered.

    For the LF398, it's typically around 150ns for positive input step and typically around 200ns for negative input step at ambient temperature.



    This aperture time won't change with the input waveform, just make sure that the input's transition during the
    delay time won't affect the desired voltage on hold capacitor.

    Is this the timing you're referring to takahiro?
    You can learn more about Sample and Hold Amplifiers in this article:
    https://www.analog.com/media/cn/training-seminars/tutorials/mt-090.pdf

    If you have further clarification, feel free to ask.
    Thanks a lot Takahiro.

    Best Regards,
    Dann

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