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WEBENCH® Tools/TPS7A8300: TPS7A8300

Vijay Moghe
Prodigy 10 points
Part Number: TPS7A8300

Tool/software: WEBENCH® Design Tools

Hi,

I am using the TPS7A8300RGWT linear regulator for my design. I have two questions.

1.)The datasheet specifies that the output capacitor should be greater than 22uF. However the TPS7A8300 EVK schematic uses 3 x 10 uF caps in parallel. Also when I used TI's Webench Tool, it recommended an output cap of 100 uF. We are limited by the size of the capacitor we can afford to use but at the same time we want good noise and ripple rejection performance. Could you please advice what is the best value and size to use for the cap for a 3.8V, 1.5 A output application?

2.)The datasheet recommends using a tantalum capacitor with low ESR to dampen ringing at the output of the regulator .Do we really need a 68uF tantalum cap or can we still get clean DC output without it?

Appreciate your help,

Thanks and best regards,

Vijay Moghe

Electrical Design Engineer, Flex

  • 0
    TI__Mastermind 23361 points

    Hi Vijay, 

    Here are the datasheet recommendation on the input and output capacitors:

    8.1.2.1 Input and Output Capacitor Requirements (CIN and COUT) The TPS7A8300 is designed and characterized for operation with ceramic capacitors of 22 µF or greater at the output and 10 µF at the input. Locate the input and output capacitors as near as practical to the respective input and output pins

    1. It's okay to use multiple smaller capacitors in parallel at the output. 

    2. Please always refer to the datasheet for the output cap requirement, TI's web bench tool may not have the correct information. 

    3. The Tantalum capacitor is only recommended with a high-Q system, that has a higher inductance. If you do see some ringing at the output during load transient at your load profiles, you could try to add the tantalum as datasheet suggested and again, this is only fo a high-Q system. 

    Regards, 
    Jason Song