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L4931 Output Capacitor

ETarver
Associate

A design I am debugging is utilizing Y5V dielectric capacitors on the input and output of the L4931. There is a 2.2uF capacitor directly at the output and another 2.2uF capacitor on the other side of an ~4 Ohm resistor that analog supplies are used off of.

Are there any concerns over temperature for using this dielectric type with this LDO? I know that Y5V tends to have a pretty variable capacitance over the operating temperature range of this LDO. I wanted to check in and see if there is any margin on the LDO for the stability capacitor requirement that would accommodate this capacitor dielectric type.

I also wanted to check in and see if there are any suggestions for performing a test for verifying if excessive transients are present due to a potential lapse in stability over temperature of the circuit. 

1 REPLY 1
MHoll.2
Senior III

That depends on the temperature range you have to cover. But Yes 2.2 uF Y5V is probably to low, the Datasheets gives 2 uF as minimal output capacitance:

MHoll2_1-1752315279750.png

You have to take in consideration not only the temperature but also the DC Bias Voltage!

MHoll2_0-1752315936301.png