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TLV1117LV: Question about output caps type

Intellectual 2705 points

Replies: 2

Views: 69

Part Number: TLV1117LV

Hi team,

My customer is using TLV1117LV33. We found that there are 2 failure parts that will randomly stop output while in normal operation. But when we re-power up the board, the part that stopped working just now can recover normal work. But if you go on running the board for about 0.5 hour, the failure part will stop output again.

We checked the schematic. Customer adds a 0.1uF cap on the input and adds 100uF+0.1uF caps on the output. The 100uF cap is an electrolytic cap and it is used to improve the transient response. 

In our latest datasheet(2015 revised version) , it said in paragraph 8.3 that 'Do not use an electrolytic output capacitor.'. However, when customer designed the schematic, they followed the old datasheet(2011 version) which doesn't mentioned that electrolytic output capacitor cannot be used. 

So I just want to check with you why we cannot use a electrolytic output capacitor for TLV1117LV? And do you think the issue happened on the 2 failure parts is related to the 100uF electrolytic output capacitor? Thanks.

Best regards,

Wayne 

  • Hello Wayne:

    It'd be helpful if you give more information on your customer's application, like Vin, Vout, load current and the voltage rating of the capacitors.  2 out of how many parts that customer tested failed? 

    Because of the limited information you provided, I don't see the direct link between the electrolytic capacitor and the 2 failure parts. Electrolytic capacitor has higher ESR/ESL than the ceramics, which cause poor transient performance of the LDOs.  The customers should avoid electrolytic capacitors in their design using TLV1117LV.

    Regards,

    Min

  • In reply to Min Hudgins:

    Hi Wayne,

    It has been more than a week without a reply. We assume the issue has been resolved, if this is not the case, please feel free to post new reply.

    Regards,
    Jason Song

    Please click the "Resolved" link at the bottom of this post if I have answered your question.

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