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TPS73801: About maximum load cap

Part Number: TPS73801
Other Parts Discussed in Thread: TPS7A3401,

Hi team,

Our customer plan to use TPS73801 and TPS7A3401 on below condition for Audio application.

●TPS73801

 Vin: 11V
 Vout: 10V
 Iout: 150mA

●TPS7A3401

 Vin: -11V
 Vout: -10V
 Iout: 150mA

In addition, These load capacitance is expected to be about 130uF for noise rejection.

We want to know these load capacitor is acceptable for these device? If are there upper limit, let me know.

Best regards,

teritama

  • Hi Teritama,

    The datasheets for these devices do not indicate a maximum capacitor, and 130uF is not extremely large, so as far as I can tell this is fine.

    Regards,

    Nick

  • Hi Nick,

    Thank you for reply. I understand this load capacitance is no problem.

    In addition, in TPS7A3401 datasheet p10 7.3.1 Internal Current Limit notes "For reliable operation, do not operate the device in current limit for extended periods of time. ". I think this is because if current limit enable for long extended periods of time, the device become hot by power loss and this may occur device damage. Is this understanding correct?

    And If there is some criterion or method to determine maximum load capacitance of LDO with current limit function in general, please teach me.

    Best regards,

    teritama

  • Hi Teritama,

    Operating at current limit accelerates failures due to electromigration because of the elevated current level, and diffusion of adjacent materials creating open-circuits over time because of the elevated temperature. 

    There is no way to determine the maximum load capacitance unless you have access to the design files. If there is a limitation by design, the datasheet will specify the maximum, and if there is no theoretical limit, the datasheet will likewise leave the upper limit unbounded. 

    Regards,

    Nick