What diode to use for a primary side rcd clamp?

Specifically the LNK616 flyback regulator.
They have 1N4007 in their dataheets/appnotes.
But the 1N4007s trrs are all over the place.
Often around 1us. The regulator has a minimum on-time of 
700ns, and really does not like surge currents.
What are better specced alternatives?

Johann Klammer wrote:
> Specifically the LNK616 flyback regulator.
> They have 1N4007 in their dataheets/appnotes.
> But the 1N4007s trrs are all over the place.
> Often around 1us. The regulator has a minimum on-time of
> 700ns, and really does not like surge currents.
> What are better specced alternatives?
> 

How about
<https://www.digikey.com/en/products/detail/comchip-technology/US1M-HF/12713336> 
?

Cheers

Phil Hobbs

-- 
Dr Philip C D Hobbs
Principal Consultant
ElectroOptical Innovations LLC / Hobbs ElectroOptics
Optics, Electro-optics, Photonics, Analog Electronics
Briarcliff Manor NY 10510

http://electrooptical.net
http://hobbs-eo.com

On 09/27/2022 09:33 PM, Phil Hobbs wrote:
> Johann Klammer wrote:
>> Specifically the LNK616 flyback regulator.
>> They have 1N4007 in their dataheets/appnotes.
>> But the 1N4007s trrs are all over the place.
>> Often around 1us. The regulator has a minimum on-time of
>> 700ns, and really does not like surge currents.
>> What are better specced alternatives?
>>
> 
> How about
> <https://www.digikey.com/en/products/detail/comchip-technology/US1M-HF/12713336> ?
> 
> Cheers
> 
> Phil Hobbs
> 
thank you.. forgot to say: it's all on perfboard.
will use UF4007.

On Tue, 27 Sep 2022 20:35:09 +0200, Johann Klammer
<klammerj@NOSPAM.a1.net> wrote:

>Specifically the LNK616 flyback regulator.
>They have 1N4007 in their dataheets/appnotes.
>But the 1N4007s trrs are all over the place.
>Often around 1us. The regulator has a minimum on-time of 
>700ns, and really does not like surge currents.
>What are better specced alternatives?

Slower diodes are used in the clamp for a reason. 
That said, I've never seen 4000 series specified there.

In4937 (from memory) often used with trrs in the >500ns 
range. Don't use ultrafast parts there. Leakage energy 
is intended to be applied into the load during clamping, 
rather than being burnt.

RL