Author Topic: Using ceramic capacitors may blow up your design...  (Read 800 times)

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Offline SteveyGTopic starter

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Using ceramic capacitors may blow up your design...
« on: July 05, 2019, 06:18:17 am »
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Offline David Hess

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Re: Using ceramic capacitors may blow up your design...
« Reply #1 on: July 05, 2019, 11:30:40 pm »
Bob Pease wrote about that a couple decades ago.  It can also be a problem when a low value input capacitor is used with a line transformer which has high leakage inductance and the input current drops rapidly like when the regulator goes into current limiting.  You might find this configuration in cheap LM317 regulators stuck on a wall-wart.

The issue was known of in the past and application notes sometimes show a low value aluminum electrolytic or solid tantalum capacitor being used instead of or in addition to a ceramic capacitor because their built in ESR improves the situation.

With a 22 microfarad ceramic capacitor in a high reliability power supply though, adding another larger electrolytic capacitor is probably not an option.  In the past they used hermetic wet or solid tantalum capacitors instead.
 
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