Lpc2000

Hi...

We make high frequency power supply equipment.

Does anybody here have any experience using the LPC2000
in a high noise environment ?

thanks,
bob

--- In lpc2000@yahoogroups.com, "bobtransformer" <bgudgel@e...> wrote:
> Hi...
> 
> We make high frequency power supply equipment.
> 
> Does anybody here have any experience using the LPC2000
> in a high noise environment ?

IMHO EMC is not really a function of a particular device, it's more 
of a system design problem.

FWIW, I just tested one of my boards (battery powered) with a 
handheld amateur radio transceiver, and it seemed very good. It 
locked up with the antenna a couple of inches away, transmitting on 
144 MHz and 433 MHz, but that would be a *very* strong field, far 
worse than anything that would normally be experienced. It was 
probably caused by the battery leads acting as an antenna. With the 
radio antenna about a foot away, there was no effect. The important 
thing is to get your PCB design right, and use transient suppressors 
appropriately, with filtering on the leads. We used this approach 
where I used to work on all our systems, and we had very few problems 
getting the equipment through the EMC tests we have to use in Europe.

Leon

I don't know if there is a vulnerability, but my hunch is that it would
show up first with the PLL -- radiated harmonics from nearby magnetics,
or stuff coupling through the load capacitors or the 1.8V power line.
The PLL is a mixer.  It will multiply any spur, and too much jitter will
make it drop lock.

You could write some s/w to generate a square wave using an output
compare pin, then run it in system with a spectrum analyzer on the
oscillator and a DSO on the output pin, looking for spurs and jitter
with and without your switching circuit running.

James Dabbs, TGA

-----Original Message-----
From: bobtransformer [mailto:bgudgel@...] 
Sent: Monday, May 17, 2004 4:22 PM
To: lpc2000@yahoogroups.com
Subject: [lpc2000] Is this part fairly noise immune ?


Hi...

We make high frequency power supply equipment.

Does anybody here have any experience using the LPC2000
in a high noise environment ?

thanks,
bob





 
Yahoo! Groups Links

That's one thing I like to do as well...  Use my handheld 5 watt 2 
meter/70 cm radio to generate a high near field.

My fear is that these 3.3 Volt parts and surrounding circuitry might 
be more susceptable to EMI than 5 Volt stuff.

Our stuff has high dV/dT which make some strong fields.

Early on in an Atmel ATMega16 design, for instance, it was very 
sensitive until I turned on the CKOPT fuse, or the fuse that runs the 
Xtal oscillator at full swing instead of their power reduce mode.

It does kinda make sense that the PLL circuit could be sensitive too.

I do know about making tight board layouts to reduce the sensitivity 
but did want to see if there was any more insight.  I've done quite a 
bit of design but this would be the first time I have done 3.3 Volt 
design.

thanks very much for the input !

bob



--- In lpc2000@yahoogroups.com, "leon_heller" <leon_heller@h...> 
wrote:
> --- In lpc2000@yahoogroups.com, "bobtransformer" <bgudgel@e...> 
wrote:
> > Hi...
> > 
> > We make high frequency power supply equipment.
> > 
> > Does anybody here have any experience using the LPC2000
> > in a high noise environment ?
> 
> IMHO EMC is not really a function of a particular device, it's more 
> of a system design problem.
> 
> FWIW, I just tested one of my boards (battery powered) with a 
> handheld amateur radio transceiver, and it seemed very good. It 
> locked up with the antenna a couple of inches away, transmitting on 
> 144 MHz and 433 MHz, but that would be a *very* strong field, far 
> worse than anything that would normally be experienced. It was 
> probably caused by the battery leads acting as an antenna. With the 
> radio antenna about a foot away, there was no effect. The important 
> thing is to get your PCB design right, and use transient 
suppressors 
> appropriately, with filtering on the leads. We used this approach 
> where I used to work on all our systems, and we had very few 
problems 
> getting the equipment through the EMC tests we have to use in 
Europe.
> 
> Leon