What is IR Drop Analysis? How it effects the timing?

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Netrapal
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Joined: Sat May 10, 2014 10:26 pm
Location: Gurgaon, India

What is IR Drop Analysis? How it effects the timing?

Post by Netrapal » Sun Jun 22, 2014 5:01 pm

What is IR Drop Analysis? How it effects the timing?

rajeshs
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Joined: Tue Jun 10, 2014 3:54 pm

Re: What is IR Drop Analysis? How it effects the timing?

Post by rajeshs » Fri Jun 27, 2014 2:15 pm

The power supply in the chip is distributed uniformly through metal layers (Vdd and Vss) across the design. These metal layers have finite amount of resistance. When voltage is applied to this metal wires current start flowing through the metal layers and some voltage is dropped due to that resistance of metal wires and current. This Drop is called as IR Drop.

For example, a design needs to operate at 2 volts and has a tolerance of 0.4 volts on either side, we need to ensure that the voltage across its power pin (Vdd) and ground pin (Vss) in that design does not fall short of 1.6 Volts.The acceptable IR drop in this context is 0.4 volts. That means the design in this context can allow upto 0.4 volts drop which does not effect the timing and functionality of design. The process of analyzing this IR Drop is called IR Drop Analysis.
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