> 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.nethttp://hobbs-eo.com
Reply by ●November 29, 20212021-11-29
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.
Reply by Spehro Pefhany●November 29, 20212021-11-29
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
Reply by ●November 27, 20212021-11-27
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.
Reply by Uwe Bonnes●November 27, 20212021-11-27
Jasen Betts <usenet@revmaps.no-ip.org> wrote:
>
> Do i recall correctly that that trick is to stick three ohms of
> resistance in series with the capacitor?
>
Three time 1 Ohm in parallel sounds better
--
Uwe Bonnes bon@elektron.ikp.physik.tu-darmstadt.de
Institut fuer Kernphysik Schlossgartenstrasse 9 64289 Darmstadt
--------- Tel. 06151 1623569 ------- Fax. 06151 1623305 ---------
Reply by ●November 27, 20212021-11-27
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.
--
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.
Reply by Charlie+●November 27, 20212021-11-27
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+
Reply by ●November 26, 20212021-11-26
On Fri, 26 Nov 2021 13:01:05 -0800 (PST), Fred Bloggs
<bloggs.fredbloggs.fred@gmail.com> wrote:
>On Friday, November 26, 2021 at 11:01:31 AM UTC-5, jla...@highlandsniptechnology.com wrote:
>> On Fri, 26 Nov 2021 07:29:01 -0800 (PST), Fred Bloggs
>> <bloggs.fred...@gmail.com> wrote:
>>
>> >On Tuesday, November 23, 2021 at 8:25:20 PM UTC-5, John Larkin wrote:
>> >> On Wed, 24 Nov 2021 00:57:44 -0000 (UTC), Jasen Betts
>> >> <use...@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?
>> >> That looks a lot like an LM1117. The LD data sheet shows polarized
>> >> output caps. Bad data sheet, like most data sheets.
>> >>
>> >> It probably likes some ESR. Lag compensation is buried inside and a
>> >> low ESR cap will add a second pole into the loop. Test one! Give it a
>> >> load step and see how much it rings.
>> >>
>> >> I know a trick for using an LM1117 with ceramic caps.
>> >
>> >Anything that self-resonates at 1MHz will keep the operation stable.
>> >
>> Please draw that for us. An LM1117 instability is typically closer to
>> 100 KHz.
>>
>> LM317 has similar dynamics, and there are (various) Spice models for
>> 317. Both like a lot of ESR in their output caps, and my trick works
>> for both.
>317 uses a completely different compensation. A SFR of 1MHz cuts in at 100kHz maximum.
What's SFR? Would you please explain that last comment?
--
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.
Reply by Fred Bloggs●November 26, 20212021-11-26
On Friday, November 26, 2021 at 11:01:31 AM UTC-5, jla...@highlandsniptechnology.com wrote:
> On Fri, 26 Nov 2021 07:29:01 -0800 (PST), Fred Bloggs
> <bloggs.fred...@gmail.com> wrote:
>
> >On Tuesday, November 23, 2021 at 8:25:20 PM UTC-5, John Larkin wrote:
> >> On Wed, 24 Nov 2021 00:57:44 -0000 (UTC), Jasen Betts
> >> <use...@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?
> >> That looks a lot like an LM1117. The LD data sheet shows polarized
> >> output caps. Bad data sheet, like most data sheets.
> >>
> >> It probably likes some ESR. Lag compensation is buried inside and a
> >> low ESR cap will add a second pole into the loop. Test one! Give it a
> >> load step and see how much it rings.
> >>
> >> I know a trick for using an LM1117 with ceramic caps.
> >
> >Anything that self-resonates at 1MHz will keep the operation stable.
> >
> Please draw that for us. An LM1117 instability is typically closer to
> 100 KHz.
>
> LM317 has similar dynamics, and there are (various) Spice models for
> 317. Both like a lot of ESR in their output caps, and my trick works
> for both.
317 uses a completely different compensation. A SFR of 1MHz cuts in at 100kHz maximum.
>
>
>
>
> --
>
> 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.
Reply by ●November 26, 20212021-11-26
On Fri, 26 Nov 2021 07:29:01 -0800 (PST), Fred Bloggs
<bloggs.fredbloggs.fred@gmail.com> wrote:
>On Tuesday, November 23, 2021 at 8:25:20 PM UTC-5, John Larkin wrote:
>> On Wed, 24 Nov 2021 00:57:44 -0000 (UTC), Jasen Betts
>> <use...@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?
>> That looks a lot like an LM1117. The LD data sheet shows polarized
>> output caps. Bad data sheet, like most data sheets.
>>
>> It probably likes some ESR. Lag compensation is buried inside and a
>> low ESR cap will add a second pole into the loop. Test one! Give it a
>> load step and see how much it rings.
>>
>> I know a trick for using an LM1117 with ceramic caps.
>
>Anything that self-resonates at 1MHz will keep the operation stable.
>
Please draw that for us. An LM1117 instability is typically closer to
100 KHz.
LM317 has similar dynamics, and there are (various) Spice models for
317. Both like a lot of ESR in their output caps, and my trick works
for both.
--
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.