Electrical – LDO 3.3V Overheats on DC input and no load


XC6206P332MR 662K 3.3V 200mA TOREX LDO Voltage Regulator SMD SOT-23

The capacitors on Vin and Vout are not too close, maybe 1cm away from the pins,
I've tried anything from 0.1uF to 22uf, Im powering the LDO from a 4.2 Lipo,
It's the second LDO from a second supplier I'm trying.

Considering my input is DC, I'm a little confused why it's overheating. It appears to be drawing 200ma.
Behaves the same with no load or if I connect a 1k resistor for some load.

I haven't tried an oscilloscope yet though to see if there's some instability.
It is my first SMD circuit, I've used non SMT 3.3v regulators before without any issues.

Ordered and soldered two new 1uf ceramic capacitors as advised, did not change the outcome however. my caps could definitely be placed a lot better.

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Best Answer

Like @peufeu states, it is not clear what voltage regulator you really were planning to use, but if we should go by the schematics, it is the LM3480, and that is what the layout is suggesting (as far as I can see from the potato vision image attached) I can tell you right away, that if you as you state in the question - were trying to mount a XC6206 on the footprint for U4 from your picture, it will of course not work as expected. Have you even read the datasheets for the parts you use? The physical pinouts are literally on the first pages of the datasheets.

This is essentially what you have connected:


simulate this circuit – Schematic created using CircuitLab

This is the block diagram for the XC6206 (Taken from the Datasheet: enter image description here

I don't think I will have to tell you why this is heating up, do I?