L5983TR Power Supply is turning off. Circuit Validation....

[Rob Ashworth]

I have a circuit with 2 L5983TR on it. On his generating a 3.3V supply the other 1.2V. 1.2V supply is fine, but the 3.3V supply is switching off. Circuit was generated using DesignSuite, and I have changed pretty much every component but to no avail. Current draw is about 200mA. Time for the scope trace is about 10 seconds.

[Patrizia BELLITTO]

Hi @Community member​ ,

first of all thanks for your interest in our product and for using eDesignSuite for your application!

From the schematic we can't understand if it can be a problem due to an incorrect layout or if the regulator reaches the current limit.

Please, be sure that:

• the expected load for 3.3V rail is always lower than 1.5 A (also in case of short and fast load transient)
• the inductor L1 saturation current is higher than 2 A (or, at least, above the maximum actual load)
• C5 and C7 are electrolytic capacitors, as suggested by eDesign, otherwise the compensation network must be redesigned

Let us know if all these conditions are verified, so in case we can go in a deeper analysis.

Thanks,

Patrizia