AN2586 Freescale Semiconductor / Motorola, AN2586 Datasheet - Page 13

• Manufacturer Part Number: AN2586
• Description: MPC8260 PowerQUICC II Family Power Distribution Trends
• Manufacturer: Freescale Semiconductor / Motorola

As mentioned earlier, the scope of this application note is the core power delivery network, even though the
ideas in this application can be extended and applied for the I/O and PLL as well. The board designer should
create an integrated environment for the chip so that all power pins have a good supply and minimum
interference occurs between these rails. We started with an attempt to model the power side of the chip so
that we can use it in our simulation, analysis, and so on. It is impractical to introduce the complex circuit
model of the internal chip blocks in the power model. The most frequent modeling technique is to model
the chip power side as a set of the following:
The simplified power module would resemble Figure 10:
As shown in Figure 11, the MPC8260 has three main power inputs:
For the grounding, the MPC8260 has the following:
MOTOROLA
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1. Core supply inputs around 2V
2. I/O supply input around 3.3V
3. PLL supply input less noisy 2V inputs
1. Main ground pins for I/O and Core current return
2. PLL ground current return pins
Is there any coupling between different power pins?
Is there any coupling inside the die itself between different power blocks?
What is the block power demand circuit model?
Current source that switches from min to max, to include the worst case scenarios.
Internal die capacitance.
Internal die resistance.
Package parasitics, inductance resistance and some capacitance.
MPC8260 PowerQUICC II Family Power Distribution Trends: A Survey
Package
Freescale Semiconductor, Inc.
For More Information On This Product,
Go to: www.freescale.com
Figure 10.
Die
Previous Work Study
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