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BQ2980: BQ298006, high side MOS leak current

Part Number: BQ2980
Other Parts Discussed in Thread: CSD83325L, CSD87313DMS, CSD17585F5

Our customers have BQ298006 + SII S-8206 designed a battery pack for smartphone.  They wonder the high side MOS, leak current is too high. Who to reduce as possible.

  • Hunter,

    I will look into the issue tomorrow once in the office.

    Thanks,
    Eric Vos
  • Hunter,

    I am sorry i never got back to you. i have looked into the FET listed on the schematic provided and i see the Gate leakage current it +/- 10uA. Unfortunately this is too high for the bq2980. The bq2980 requires the Leakage current to be < 1uA. Here is a list of recommended FET's that satisfy this requirement  as per their datasheet. 

    1. OnSemi - EFC8811R, EFC6602
    2. Renesas - RBK01P10GQT, PA2396T1P
    3. Panasonic - DSMKA280L, FC6H21680L
    4. AOS – AOC3860
    5. TI – CSD83325L 
    6. TI - CSD87313DMS
    7. TI - CSD17585F5

    If you have any other questions please let me know. 

    thanks,

    Eric Vos

  • How to calculate Gate leakage current effect on BQ2980? Thanks.
  • Hunter,

    Unfortunately there is no simple equation to use. The best thing to do is to test using the desired FET. The simple procedure is as follows.

    1) If the FET is the same package size i recommend to use the TI bq2980 EVM and swap out the TI FET and the new one

    2) Connect a source meter to Bat+/Bat-

    3) Monitor the current coming out of the source meter as you sweep the voltage over the full battery voltage range. 

    4) The current will be noisy because the larger the leakage current on the FET the more the charge pumps will be toggled on and off to keep the CHG/DSG pins high. Be sure to take lots of measurements as quick as you can and average them.

    Thanks,

    Eric Vos