what are remedies for IR drop

[rake.405]

can any body tell me abt the remedies for IR drop
Thanks in advance

 

[gen0357]

Following could be the solution

For static IR drop : revise your power N/W (Increase the no. of power strips etc.)

For dynamic IR drop : Insert the Decap cells.

 

[Goldeneagle]

For static IR .. you can even widen the metal if there is room for doing so..

 

[itsmeteja]

you can even add extra power sources for reducing the static IR drop.

For reducing the dynamic, use less drive strength cells.

 

[useless_skew]

If the IR drop is concentrated at one particular location, spread out the cells in that region if possible.

 

[pavanks]

For IR drop best would be putting more power straps and if the power drop is small then u can widen the strap so that u meet the power.

For Dynamic IR drop first u try to dec the strength for the non critical paths(not a good practice as this might cause many timing violations). Best would be to put de cap cells but at the cost of more leakage and area.

 

[lohi21]

My experince on the Static Ir is, adding additional stripe would only enhance the the design by 10 -20%, consider the switching factor is too high. but still gets reported of drop. Combinations of Decaps cells, and well planned power stripe would definately be plus.

In spite of all these, If drop still fails, Have an extra pad, and that would spin off the whole design again.

 

[yadavvlsi]

Check this thread..
https://www.edaboard.com/threads/217088/#2

 

[huckle]

wouldn't adding redundant vias on signal nets reduce IR drop too? anyone agrees/disagree?

 

[samvelc]

can any body tell me abt the remedies for IR drop
Thanks in advance

IR-Drop Solutions:
1. Reduce the current consumption of the cell
2. Add more supply voltage pads
3. Reduce the wire resistance
4. Use multiple power layers
5. Add decoupling capacitors

 

[pavanks]

wouldn't adding redundant vias on signal nets reduce IR drop too? anyone agrees/disagree?

I dont think it will help u much in dec the drop in that area.
But if the drop margin is very small then u can try this also.
You need to add redundant vias for EM violations.

 

[huckle]

IR-Drop Solutions:
1. Reduce the current consumption of the cell
2. Add more supply voltage pads
3. Reduce the wire resistance
4. Use multiple power layers
5. Add decoupling capacitors

Can you please explain #4, 'use of multiple power layers'. Thanks,

 

[VENKATESHM]

can any one explain me how decoupled cap will reduce the IR drop

 

[lohi21]

can any one explain me how decoupled cap will reduce the IR drop

Capacitance in non-switching state that can source as well as sink current.Decaps filter out current spikes resulting from simultaneous switching of signals.
Decap Elements are Effective Series Capacitance (ESC), Effective Series Resistance (ESR)

 

[yadavvlsi]

@huckle: I think he means use more layers to supply power. Using more metal layers will reduce resistance of power network and hence IR drop.
@VENKATESHM: Decoupling capacitors acts as local charge storage and is helpful in mitigating the voltage drop at supply points by providing charge. It reduces current drawn from power supply and Hence IR drop.

 

[VENKATESHM]

what is Effective Series Capacitance (ESC), Effective Series Resistance (ESR)

 

[pavanks]

This i feel will have a very little impact on the dynamic power.