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TPL0202-10, bypass capacitor

Shinichi Inoue
Guru 21566 points
Other Parts Discussed in Thread: TPL0202-10

Dear Specialists,

My customer is considering TPL0202-10 and has a question?

Could you please advise?

The datasheet of P.26 of 10.1 Layout Guidelines describes

• Apply low equivalent series resistance (0.1 µF to 10 µF tantalum or electrolytic capacitors) at the supplies to minimize transient disturbances and to filter low frequency ripple.

Is it possible to use ceramic capacitor for bypass cap?

Depend on the end customer, it can't use tantalum and electric capacitor.

I appreciate your great help.

Best regards,

Shinichi

  • 0
    Guru 74080 points
    I would prefer ceramic capacitors instead of tantalum or electrolytic.
  • 0
    Guru 316440 points
    Ceramic capacitors have lower ESR than other types, so they are even better suited.

    That sentence is probably a relic of older times when there were no large ceramic capacitors.
  • 0
    Guru 74080 points
    There are a few regulators, for example, that do not like too low ESR capacitors at their output, but this is not the case here, so I agree to Clemens - they might be even better and I also agree that this might come from an earlier time where ceramics were not available or way too expensive with large capacitances although the datasheet is from 2010 which isn't that early.
  • 0
    Genius 5505 points

    You should understand an effect of using capacitors in circuit by yourself. Use simulation tools if needed, or mathematical approximation. The specific value can vary from pF to mF, depending on conditions. The capacitors are always necessary evil, because your transient response on fast-ON/OFF conditions are also increasing in time, phase and peak current limits. In some cases digital and analog rails should be completely isolated/decoupled from each other, including RF shielding. Sometimes, when high SNR and bandwidth is needed on analog side, only specific technics can yield good result, based not on capacitors, of course.

  • 0
    Genius 5505 points

    Even chosen digital potentiometer has quite limited bandwidth, so be careful not to use it in feedback circuit directly, - you can loose your high frequency portion of the signal.

  • 0 in reply to Alexey Bagaev
    Guru 21566 points

    Dear ALL

    Thank you for your kindly replies so mamy.

    I understand ceramic capacitor can use for bypass capacitor, and I am going to suggest to test by himself. 

    In addition, I tell  that TPL0202 is not suitable for the high frequency.

    I really appreciate your great help and cooperation.

    Best regards,

    Shinichi

  • 0 in reply to Shinichi Inoue
    Genius 5505 points

    No, no. The documentation clearly specified the bandwidth of this device - 2MHz. Just put this into account, when use it in amplification feedback. Digital potentiometers with higher resistance (100kOhm) have too low bandwidth for most amplification feedback applications - 50 kHz.