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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?
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?
--
Jasen.
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.
--
If a man will begin with certainties, he shall end with doubts,
but if he will be content to begin with doubts he shall end in certainties.
Francis Bacon
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.
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.
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.
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?
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+
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.
Three time 1 Ohm in parallel sounds betterDo i recall correctly that that trick is to stick three ohms of
resistance in series with the capacitor?
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?
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?
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 storedOn 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.