Ground plane for flyback

hithesh123 said:

Also, the design did not have a Y2 cap. Maybe its not required at this power!

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Hi Hithesh,
You must it know _its for your application, but a forseehen is never negative, but the most cheap solution for a possible changing!
I wil not say, that your switcher will not good works, but maybe other equipments in hes environment no more_because they would be disturbend! :-(
Otherwise: EMC problems can you have from (only)some Watt switcher upwards... :-(
Its not so easy to say, that i.e. below 20W isnt a issue!
I have had a similar TOPswitch project for a global provider so 3 years ago(=> 16W output as peak/generell ca. 5W), the layout was routed from a "PCB" departement >> only after 3th(!) version are the EMC tests approved! :-( ,& the persons are not very beginner - over 15 years pro head experience _in generell routings_, and it has had Y & X capacitances too ...
The plus developments costs are more as € 100K for the corporation, and the mass production has become a delay of over a half year_only concurrents are happy...
Greetings!
K.

You can-should have GND planes in SMPS world too, but its more sensitive as some other designs.
You must see for spiting between "normal current" parts & switcher/diode returns i.e., than by FB & eventually sensing at the load...

Hi dick99,
If you evenually will read the full posts you will see that these was the biggest subject for us & is in my opinion so soluted too...
Refer pls minimum to my before past posting from: 22 Jul 2010 21:36 .
Regards!
K.