Timeline for AMS vs LD vs ZLDO vs NCP in 1117 Linear Regulators
Current License: CC BY-SA 4.0
6 events
| when toggle format | what | by | license | comment | |
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| Jan 27, 2019 at 22:50 | comment | added | Bruce Abbott | "Or use a tantalum" - exactly. Use a capacitor type that is known to work with both variants and you won't have a problem - with the bonus of being able to substitute without fear. The 1117 regulator is a generic part that many manufacturers produce, but I bet they all have slight variations that can get you into trouble if you rely on exact behavior. | |
| Jan 27, 2019 at 15:27 | comment | added | D.A.S. | Bruce, @SpehroPefhany is correct , It 's the Lead-lag effect of the cap's RC value that determines stability and the Source must be much lower than the Load Cap hence MLCC in to Solid Tant Out. unless your MLCC cap is at least 10x 200ns or 2us which I doubt it will ring with steps which the ESR*C Value Attenuating feedback (f) is cause fo more ringing | |
| Jan 27, 2019 at 8:50 | comment | added | Spehro 'speff' Pefhany | The LM1117 (original manufacturer) specifies minimum ESR of 300m\$\Omega\$, the NCP1117 specifies minimum ESR of 33m\$\Omega\$. The capacitor forms part of the frequency compensation of the regulator so ignoring the minimum ESR is not a good idea. For example, some fraction of them might oscillate straightaway, or perhaps at temperature extremes. A small resistor in series with the ceramic cap will make sure it's okay. Or use a tantalum. | |
| Jan 27, 2019 at 8:29 | comment | added | Bruce Abbott | @SpehroPefhany And no indication that it isn't. I didn't say it was 'the same' only that both will work with the same tantalum capacitor. In reality the only difference might be that AMS didn't test theirs with a ('Low' ESR, whatever that means) ceramic capacitor. I can't see a date on the AMS datasheet, but the file was created in 2009. Were 22uF 'Low ESR' ceramic capacitors commonly used back then? | |
| Jan 27, 2019 at 8:05 | comment | added | Spehro 'speff' Pefhany | NOT the same. There is no indication the AMS1117 is stable with a (low ESR) ceramic capacitor! | |
| Jan 27, 2019 at 7:54 | history | answered | Bruce Abbott | CC BY-SA 4.0 |