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Concept
Power Integrity (PI) is One of Noise Factor
Trend in IC and PI Issue
Since the IC chip becomes more speedy at low voltage, power noise problem has been increasing.
On the power distribution network (PDN) from battery, the IC consumes current and it causes voltage drop relevant to IC malfunction problem. Therefore less impedance in the PDN is better to avoid noise problem. However, even though recent of IC chip consumes low voltage, current speed is very fast. (See figure: Trend in IC)
In the recent IC, switching current peak increases constantly, against this, power voltage drop occures at the same timing. (See figure below)
PI problems sometimes causes unmatched clock rhythm because of this voltage fluctuation. To avoid this problem, you need to put capacitors around critical IC and achieve impedance.
PIStream can eliminate input impedance, transfer impedance and DC relevant to voltage drop at design phase like EMIStream, and visually you can consider how to fix the problem. By doing this at design phase, you will be able to save your PCB development time and money. PIStream enebles engineers to provide a simple to use, quick response and absolute high quolity product to help answer engineers' needs.
Jitter generation caused by voltage fluctuation
The reference clock jitter and analog voltage fluctuation degrades eye pattern.
Since the jitter is caused by PI issue, there is limitation on suppressing jitter by only using SI tools. The following figure shows the effect before and after added filter for power IC. After added filter, eye diagram became more clear and wider eye opening.
Verifying Analysis Accuracy
The following graph shows compalison between actual mesuremsnt (Blue line) and PIStream calculation (Pink line) result. S21 calculated by PIStream and S21 by actual measurement shows correlation up to 3GHz. So that PIStream cannot calculate S21, it uses output analysis model.
* EMIStream and PIStream are both registered trademarks or trademarks of NEC Informatec Systems, Inc. in the United States and/or other countries.
