Just take note all the resin/hardeners we used are for functional
use intellectual property protection. IP is a bit confusing to use
here since it does help the Ingress Protection (IP65/67 etc).
I think dedicated attacker will always find a way to circumvent your 
protection methods for such power supply circuits. There are plenty
of hackers out there specializing in read out the code protected PICs
or other MCUs as well. I think Microchip has a standard
disclaimers in front of the datasheet named "Note the following
details of the code protection feature on Microchip devices".

The last clause is as following:
************Quote from Microchip datasheets *****************
Neither Microchip nor any other semiconductor manufacturers can
guarantee the security of their code. Code protection does
not mean that we are guaranteeing the product as "Unbreakable".
************End of quote*************************************

Regards,
Xiaofan

-----Original Message-----
From: Chen Xiao Fan 
Sent: Thursday, September 22, 2005 10:24 AM
To: 'Microcontroller discussion list - Public.'
Subject: RE: [EE]: Potting compound to protect IP?

Hot glue is often used in power supply design to secure the
discrete components again vibration. Still it is not good for
your application. So maybe some resin/hardener can be used. 

For example, in one fieldbus terminator I developed some years
ago, I use Wevo PU403FL resin and the corresponding hardener.
There are some other types like the Epoxylite EIP 4236 Resin
and hardener which may be better for your application. CY221
is the most commonly used potting compound here and maybe it
is already good for you. It is cheaper than Epoxylite.

Regards,
Xiaofan
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