LD1117 capacitor

On Sat, 27 Nov 2021 22:37:23 -0000 (UTC), Jasen Betts
<usenet@revmaps.no-ip.org> wrote:

>On 2021-11-27, jlarkin@highlandsniptechnology.com <jlarkin@highlandsniptechnology.com> wrote:
>> On Sat, 27 Nov 2021 06:58:33 +0000, Charlie+ <charlie@xxx.net> wrote:
>>
>>> On Wed, 24 Nov 2021 00:57:44 -0000 (UTC), Jasen Betts
>>><usenet@revmaps.no-ip.org> wrote as underneath :
>>>
>>>>The LD1117 data sheet makes no mention of what type of 10uF capacitor to
>>>>use at the output. is it stable with ceramic there or does it, like the
>>>>LM1117, need something with more ESR?
>>>
>>>Take a look at the Datasheet for the NCP1117, it has specific
>>>information on the cap types and ESR values. C+
>>
>> If you're powering ICs, logic or opamps or whatever, you would
>> probably have a mess of low-ESR ceramic bypass caps scattered about
>> the schematic. What works there is one tant or alum cap to furnish the
>> bulk ESR, and then the ceramics. That's not on any data sheet, but it
>> works.
>>
>> Or use my trick for all-ceramic loads. 
>>
>
>Do i recall correctly that that trick is to stick three ohms of
>resistance in series with the capacitor?

No. Why wreck a perfectly good capacitor?



-- 

Father Brown's figure remained quite dark and still; 
but in that instant he had lost his head. His head was
always most valuable when he had lost it.



  

On Wed, 24 Nov 2021 00:57:44 -0000 (UTC), Jasen Betts
<usenet@revmaps.no-ip.org> wrote:

>The LD1117 data sheet makes no mention of what type of 10uF capacitor to
>use at the output. is it stable with ceramic there or does it, like the
>LM1117, need something with more ESR?

Stick a few ohms 0603 resistor in series with the ceramic and be on
the safe side. 

-- 
Best regards, 
Spehro Pefhany

On Mon, 29 Nov 2021 09:07:55 -0500, Spehro Pefhany
<speffSNIP@interlogDOTyou.knowwhat> wrote:

>On Wed, 24 Nov 2021 00:57:44 -0000 (UTC), Jasen Betts
><usenet@revmaps.no-ip.org> wrote:
>
>>The LD1117 data sheet makes no mention of what type of 10uF capacitor to
>>use at the output. is it stable with ceramic there or does it, like the
>>LM1117, need something with more ESR?
>
>Stick a few ohms 0603 resistor in series with the ceramic and be on
>the safe side. 

I have boards with power pours, ceramic caps everywhere, and I don't
want to add ESR and ESL to every cap.

So hang a big tantalum on the output to damp things, or add one small
ceramic cap from the ADJ pin to ground.

https://www.dropbox.com/sh/3kc40u7evj5kz42/AACOPUL3V63PsEtN5l_w3pYga?dl=0




-- 

Father Brown's figure remained quite dark and still; 
but in that instant he had lost his head. His head was
always most valuable when he had lost it.



  

Spehro Pefhany wrote:
> On Wed, 24 Nov 2021 00:57:44 -0000 (UTC), Jasen Betts
> <usenet@revmaps.no-ip.org> wrote:
> 
>> The LD1117 data sheet makes no mention of what type of 10uF capacitor to
>> use at the output. is it stable with ceramic there or does it, like the
>> LM1117, need something with more ESR?
> 
> Stick a few ohms 0603 resistor in series with the ceramic and be on
> the safe side.
> 
Provided it's pulse rated.  An output short will dump the entire stored 
energy of the cap into that poor resistor in a microsecond or so.

Cheers

Phil Hobbs

-- 
Dr Philip C D Hobbs
Principal Consultant
ElectroOptical Innovations LLC / Hobbs ElectroOptics
Optics, Electro-optics, Photonics, Analog Electronics
Briarcliff Manor NY 10510

http://electrooptical.net
http://hobbs-eo.com