(electronic) signal integrity list ()

martinos72 | 1 Aug 2012 11:14

hyperlinx: plane noise Vs Z profile

Dear All,
Working with linesim I have designed a very simple pds that include a couple of plane, a vrm, a C, and one IC
PIN. Very easily I have extract the z profile up to 100Mhz in the IC pin area.

Then I have tried to run the plane noise simulation after have applied a sinusoidal stimulus to the IC pin.

My question is: why I am not able to get the same voltage noise value from the two analisys?

Example:
1. From decoupling analisys at 20Mhz, Z=0.1 ohm if I=0.5A V ripple would be 50mV
2. From voltage noise tool giving to the IC pin a sinusoidal stimulus IMAX=0.5A freq.=20Mhz the max ripple
measured on the IC area is alway considerably smaller =28 mV.

Many thanks
Oscar

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McKinney, Steven | 1 Aug 2012 18:05

Re: hyperlinx: plane noise Vs Z profile

Hi Oscar,

Based on what I think you are trying to do (correlation to some measured results), I would use a current
stimulus with an edge instead of the sinusoid.  Specifying an edge will give you more control over the
frequency content in the current waveform and represent the switching behavior of the IC better.  If you
were trying to model power supply noise coming off your switching mode power supply, that's where you want
to use the sinusoid.   Sorry I didn't get a chance to reply to your community yet post by the way....

-Steve

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Subject: [SI-LIST] hyperlinx: plane noise Vs Z profile

Dear All,
Working with linesim I have designed a very simple pds that include a couple of plane, a vrm, a C, and one IC
PIN. Very easily I have extract the z profile up to 100Mhz in the IC pin area.

Then I have tried to run the plane noise simulation after have applied a sinusoidal stimulus to the IC pin.

My question is: why I am not able to get the same voltage noise value from the two analisys?

Example:
1. From decoupling analisys at 20Mhz, Z=0.1 ohm if I=0.5A V ripple would be 50mV 2. From voltage noise tool
giving to the IC pin a sinusoidal stimulus IMAX=0.5A freq.=20Mhz the max ripple measured on the IC area is
alway considerably smaller =28 mV.

(Continue reading)