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Topic: Resinator v Crystal (Read 761 times) previous topic - next topic

retrolefty


yes ive mounted my Resinator right next to 9 and 10 pins, im actually using 2 328's cant really mount it in a metal box ive tryed all sorts of metal shielding which seems to make interference worse for some reason think it acts like an airel, the emf travels straight through double sided copper, does some real strange things

thats got me thinking we used "mew" metal years ago for something we made years ago,  might give that a try see if that helps.

what ive made works, just trying to help it further if i can



I believe the term is Mu metals and google will show you suppliers and info.

Lefty

dc42

Mumetal is for shielding devices from constant magnetic fields. It won't help protect against EMI any better than a metal box will, unless the EMI takes the form of low frequency magnetic fields.

To protect against intense EMI, you need to enclose the circuit in a metal box - typically with a conductive gasket between the two halves - and also prevent EMI entering via the inputs and outputs. This is done by a combination of designing the input and output wiring so as to minimize EMI pickup, any by using RC or LC networks in the input and output circuits.

If you use a crystal, you should connect the metal case to ground if you expect EMI to be a problem.
Formal verification of safety-critical software, software development, and electronic design and prototyping. See http://www.eschertech.com. Please do not ask for unpaid help via PM, use the forum.

SirNickity

The crystal enclosure is a metal box, but I don't think it's grounded.  Maybe it's possible to solder a lead from the case to ground?  Also, make sure your enclosure is grounded.  It will pick up EMF, and then it will shunt them to ground.  This is what you want.

oric_dan

When it comes to EMI pickup, I would think the xtal is the last thing to worry about.
The thing to worry about is all those long traces on the board that have somewhat
high impedances w.r.t. ground, as well as all those even longer wires connecting the
board to the outside world. Even if you shield the board, you still have those wires to
deal with. That's where you need to concentrate on EMI rejection.

jonisonvespaa

on my first board design i had top bottom 100% "gnd" fill on my board which didnt work too well

i did think of maby trying 100% top/bottom "Earth" fill to reduce noise, really unsure of this though, not sure what noise will come up the earth,  making the gap between the fill and tracks pads objects ect, quite big

the board is inside a plastic box so cant really do anything with this.

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