RE: [SI-LIST] : Micro Noise

About this list Date view Thread view Subject view Author view

From: Chris Cheng (hycheng@3pardata.com)
Date: Fri Nov 05 1999 - 10:35:54 PST


have u look into using spread spectrum clock source instead of crystals ?
chris

> -----Original Message-----
> From: owner-si-list@silab.eng.sun.com
> [mailto:owner-si-list@silab.eng.sun.com]On Behalf Of Lfresearch@aol.com
> Sent: Wednesday, November 03, 1999 7:31 AM
> To: si-list@silab.eng.sun.com
> Subject: [SI-LIST] : Micro Noise
>
>
> Hi all,
>
> I have a problem with a microprocessor which appears to be radiating very
> strongly from the package. I've deactivated all other circuits ( pulled
> crystals, pins etc ) on the board. Additionally, the micro is
> held in reset,
> PROM's are pulled, but it's a noisy as heck. Close field probes

> both E and
> H field ) show the package to be the dominent source of radiation.
>
> The device has a maximum clock rate of 50 MHz, this is where
> we're using it.
> Clock it at 32 MHz and the emissions fall about 10 dB up to about
> 300 MHz,
> more above 300 MHz. Yes it's a CMOS device.......
>
> Am I stuck with putting a can over the chip? The product has a plastic
> package, so there is no shielding available at all.....
>
> Thanks,
>
> Derek
>
> **** To unsubscribe from si-list: send e-mail to
> majordomo@silab.eng.sun.com. In the BODY of message put:
> UNSUBSCRIBE si-list, for more help, put HELP. si-list archives
> are accessible at http://www.qsl.net/wb6tpu/si-list ****
>
>

**** To unsubscribe from si-list: send e-mail to majordomo@silab.eng.sun.com. In the BODY of message put: UNSUBSCRIBE si-list, for more help, put HELP. si-list archives are accessible at http://www.qsl.net/wb6tpu/si-list ****


About this list Date view Thread view Subject view Author view

This archive was generated by hypermail 2b29 : Tue Feb 29 2000 - 11:39:38 PST