EMC emissie problem

[marco32]

Posted on October 27, 2006 at 04:46

EMC emissie problem

[marco32]

Posted on September 29, 2006 at 12:33

I've done some EMC emissie test on pcb track niveau.

Above the ST72C334 i found an strong 8Mhz emissie. (clock frequency)

My college have experience with PIC.

The Pic doesn't have such a strong Emissie.

Do i something wrong on PCB?

I have a multilayer with a ground layer.

Marco.

[info45]

Posted on October 08, 2006 at 06:38

Hy Marco,

I think tha You use a extenal cristal or resonator, at 16MHz?

Try to put 100nF capacitors near to Vcc ans gnd micro pins.

Is better to connect gnd pins in short gnd track

PIC micro don't have this problem if using internal oscillator....

Bye

[pete3]

Posted on October 11, 2006 at 09:56

Marco,

This might help:

http://www.st.com/stonline/books/pdf/docs/4967.pdf

[marco32]

Posted on October 11, 2006 at 13:00

Thanks for you're replies,

I use a 8Mhz resonator

Also there are 10nF capacitors near to the Vcc.

The ground is a full layer.

Also read all the different documents on the ST site.

And still a strong emissie :|

[pete3]

Posted on October 11, 2006 at 13:06

It's hard to say any more without a layout diagram. Can you post one?

[marco32]

Posted on October 27, 2006 at 04:46

Here is the schematic off the control board.

(Acrobat reader)

________________

Attachments :

MT0080_1.pdf : https://st--c.eu10.content.force.com/sfc/dist/version/download/?oid=00Db0000000YtG6&ids=0680X000006I05B&d=%2Fa%2F0X0000000bWJ%2Ffwyr7NB0A7oxZjV_u7EIYqht8kCbonvtBK6ZcN0GfkA&asPdf=false