Bob Barr wrote:

>On Tue, 15 Nov 2005 08:31:11 -0500, Olin Lathrop wrote:
>
>  
>
>>Bob Barr wrote:
>>    
>>
>>>According to the datasheet for the USB chips, the capacitor between
>>>the regulator output and ground should be 200 nF (0.22 uF) +/- 20%.
>>>      
>>>
>>This is in the writeup in the USB peripheral chapter.  The specification in
>>the electrical characteristics section contradicts this.  The minimum
>>capacitance is higher than 220nF-20% but the maximum is left open.  I asked
>>Microchip for a clarification on this a couple of weeks ago.  The
>>preliminary answer I heard is that 220nF+20% is not an upper limit as the
>>writeup implies, and that more than 220nF is in fact a good idea.  Their own
>>board uses 470nF if I remember correctly.  I asked if 1uF ceramic would be
>>OK, and so far they've said it probably is, but I haven't gotten a
>>definative answer yet.
>>
>>    
>>
>
>Thanks, Olin. You're right, I was going by the write-up and neglected
>to confirm that value in the specs section. It's clearly listed as 220
>nF minimum as parameter D324.
>
>
>Regards, Bob
>
>  
>
I've searched for that kind of information in different documents, but 
still didn't found that. Where can I find that kind of values? I've 
already searched in the datasheet of the chips, and the reference manual.

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