What diode to use for a primary side rcd clamp?...

[Johann Klammer]

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?

 

[Phil Hobbs]

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

 

[Johann Klammer]

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.

 

[legg]

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