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TPS7A84: Cin and Cout when Iout=1.2A

Given Ding
Genius 10165 points
Part Number: TPS7A84
Other Parts Discussed in Thread: , TPS7A83A

Hi ,

just want to check if Cin=10uf and Cout=2x10uf is OK when Iout max=1.3A

  • 0
    TI__Guru 55940 points

    Hi Given,

    TPS7A84 is designed, characterized, and tested for operation with a minimum input capacitor of 10 uF and a minimum output capacitor of 47 uF.

    Please also consider using TPS7A84A for this design.  This is the updated pin-to-pin compatible version of TPS7A84 with more flexibility during startup. 

    Due to your maximum current of 1.2 A, you could also consider TPS7A83A which is the 2 A version of this device.  The minimum output capacitor for TPS7A83A is 22 uF.

    Very Respectfully,

    Ryan

  • 0 in reply to Ryan Eslinger
    TI__Genius 10165 points

    Hi Ryan,

    Thanks for your reply.

    One more thing, regarding the Cin and Cout requirement in the datasheet, is temp or capacitance derating being considered, that is, what's the effective capacitance requirement? Thanks.

    For example, for TPS7A83, a 22uf or larger Cout is needed. So I just put a 22uf cap on Cout, is there voltage rating requirement？

    BRs

    Given

  • 0 in reply to Given Ding
    TI__Guru 55940 points

    Hi Given,

    For our linear regulators we state capacitor values with our requirements.  Customers will need to look into how their specific capacitors derate during their capacitor selection process.  We generally state our capacitor requirements assuming 50% derating.

    LDO basics: capacitor vs. capacitance
    Low-dropout regulators (LDOs) provide power in all types of applications. But for an LDO to operate normally, you need an output capacitor. A common issue when designing LDOs into an application is selecting…
    By in Technical articles > Power management

    For more information specific to TPS7A84A, please refer to sections 8.1.1.6 Recommended Capacitor Types and 8.1.1.7 Input and Output Capacitor Requirements (Cin and Cout) of the datasheet.

    Very Respectfully,

    Ryan