ZMR330: 3V3 Linear regulator needs diode connected cathode to input voltage?

[treez]

Hi,
Question as per title.

ZMR330 datasheet
https://www.diodes.com/assets/Datasheets/ZMRSERIES.pdf

..the datasheet doesnt say such a diode is needed. Would we need one.

We are using it with Vin=12v and vout = 3v3

 

[KlausST]

Hi,

A bit more infirmation, please.
Why do you ask? .... when the datasheet does not mention it.

Klaus

 

[FvM]

I can imagine three different ways to connect the anode (OUT, GND, Supply+), please ask a clear question.

 

[Audioguru]

It is a useless datasheet that does not show a circuit and does not show the input and output capacitors that every other voltage regulator uses.

 

[treez]

Thanks, i mean a diode connected anode to output, cathode to input...
in the old days, such a diode was always needed to protect the regulator in those cases wherever vout gets bigger than vin.

 

[KlausST]

Hi,

n the old days, such a diode was always needed to protect the regulator in those cases wherever vout gets bigger than vin.

True. It was not always needed. Only when the output goes higher than the input. Is this the case with your application?

Klaus

 

[betwixt]

It is a useless datasheet that does not show a circuit and does not show the input and output capacitors that every other voltage regulator uses.

True - but it does say 'unconditionally stable' and the transient response graphs are labeled to say there is no output capacitor.

I can't see any reference or requirement for a external diode anywhere. Bear in mind the output voltage is only 3.3V and a parallel protection diode would only conduct if the input voltage was about 2.7V or less. I would think the chances of internal breakdown quite small, the pass transistor can probably withstand it easily.

Brian.