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low forward drop and reverse leakage current device

vaibhav waman
Intellectual 320 points
Other Parts Discussed in Thread: TPS22916, TPS22976, LM66100

I am looking for device which has very less forward voltage drop and reverse leakage current(less than 100nA at 85 Temperature. I will use this device to charge supercapacitor and then to power RTC chip.

Input voltage rating is 3.3v.

  • 0
    TI__Genius 10855 points

    Hi Vaibhav,

    Thanks for reaching out on E2E!

    We have a few devices that might work here. We have integrated load switches with integrated reverse current protection, such as the TPS22916. However, the reverse leakage current is slightly higher than 100nA.

    If you need a device that has less leakage current, you will need to use back-to-back FETs. From a load switch perspective, you could use a dual channel device such as the TPS22976 in a B2B configuration, as shown in section 10.1.4.

    Let me know if you have any questions!

    Thanks,

    Arthur Huang

    To find the latest information on Power Switches, visit www.ti.com/powerswitch

    Please click "This resolved my issue" button if this post answers your question.

  • 0 in reply to Alpha H
    Intellectual 320 points
    Hello Arthur,

    TPS22976 looks promising solution for me. but in datasheet it is not mention reverse leakage current for this switch or It will have zero reverse leakage current when use in back to back configuration ?
  • 0 in reply to vaibhav waman
    TI__Genius 10855 points
    Hi Vaibhav,

    Taking another look, it might be difficult to achieve <100nA of reverse leakage current with any of our devices.

    I'm trying to think of some potential solutions here, but the closest we can get would be the TPS22916. You could also look at our Ideal Diode Controller page to see if a different device could work instead: www.ti.com/.../products.html

    Even discrete diodes / FETs will still have reverse leakage current in the range of uAs, with worse voltage drop. What are your thoughts?

    Thanks,
    Arthur Huang
  • 0 in reply to Alpha H
    Intellectual 320 points

    Hello Arthur,

    Yes, I can not use discrete because if I choose diode with less leakage current then forward voltage drop increases. Basically my application has 3.3V supply RTC chip and I want to keep this RTC power on in absence of 3.3V using supercapacitor.so to keep RTC on for longer duration few nano ampere of current loss matters too much. So now I am came to opinion that I should use back to back mosfet configuration.if you can sugest me something to charge supercapacitor with no voltage drop and also very less reverse leakage current.

  • 0 in reply to vaibhav waman
    TI__Genius 10855 points
    Hi Vaibhav,

    Unfortunately, even B2B FETs will still have voltage drop across the body diode when the blocking FET is active. Discrete FETs would also have reverse leakage current in this scenario. The closest equivalent would be using the TPS22916 or an ideal diode such as the LM66100.

    Thanks,
    Arthur
  • 0 in reply to Alpha H
    Intellectual 320 points
    Hello Arthur,

    Thank you very much for support.
    In TPS22916 if I have 3.3V at output pin and input at 0V also ON pin is disabled, What will be current from output to input ?
    and in this condition does device block current only when reverse current will reach 500mA ? if yes how much time it will flow 500mA from output to input till current blocking ?
  • 0 in reply to vaibhav waman
    TI__Genius 10855 points
    Hi Vaibhav,

    If you have 3.3V at the output pin and 0V at the input, you'll have IIN, RCB of reverse leakage current (300nA).

    The reverse current blocking will activate when the reverse current reaches 500mA, within 10uS. You can see more of the technical parameters in the electrical characteristics of the TPS22916 datasheet.

    Thanks,
    Arthur