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TPS61041 and TPS7A4901 output/input capacitors

Other Parts Discussed in Thread: TPS61041, OPA4314, TPS61040


I'm working with the TPS61041 and TPS7A4901 to power an audio amp. The TPS61041 steps up a single cell lithium battery to around 5.85V and the TPS7A4901 regulates and cleans this down to 5.5V. Op amps in the audio chain are single supply (OPA4314) and their virtual ground is derived from the 5.5V supply hence 5.5V must be very clean.

The TPS61041 reference design calls for a 10uF output capacitor and the TPS7A4901 reference design calls for a 10uF input capacitor. Since these two IC's are right next to each other on the board, do I really need both these capacitors? Will one suffice? Typical output current from the TPS7A4901 is 50mA.

Finally, is there a different IC combination that you would recommend that is preferred to the above approach?

Kind regards,


  • Andrew,

    First, I suggest you to use TPS61040 instead of the TPS61041. TPS6040 can't output the power you needed while the TPS61041 is just fit.

    The most important cap for a Boost converter is its output cap. The most important cap for the Buck converter is the input cap. In your applicaiton, Boost followed by a BUCK, I suggest you use two caps seperately to have a good decoupling. And The Ouput cap of the Boost converter should be as close to the Boost IC as possible. The input cap of the Buck converter should be as close to the BuCK IC as possibel. Thus will have the best performance.


  • Hi Helen,

    Thank you for your reply. I would like to check one thing. The current drain on the TPS7A4901 is 50mA and, assuming the part is 90% efficient, the input current will be no greater than 55mA. The TPS61041 is rated at 250mA. When you say the TPS61041 cannot supply the power I need, what am I missing? It looks to me like it has plenty of power.

  • 250mA means peak switch current. 55mA output current convert to the peak switch current, it will be much higher than 250mA, around 400mA. So please use TPS61040 instead of TPS61041