Info about LVT, HVT and SVT cells and their impact on low power designs

[sahana]

Hi can anybody attach a document regarding HVT, LVT, SVT cells and their impact in LOW Power Designs?


sahana

 

[viju]

hvt svt

HVT = high V threshold. Can be used in the path where timing is not critical. So by using HVT cells we can save power.
LVT - Low V threshold. One should use these cells in timing critical paths. These cells are fast but , comsumes more power due to its leakage. So it will consume more power. So use only when timing is critical.
SVT- Standard V threshold. Best of both world. Medium delay and medium power requirment. So if timing is not met by small magin with HVT, you should try with SVT. And at last LVT.

Hope this basic helps....

You can refer Low power methodology manual available from synopsys.

It would be great if some one can attach the detailed document for the same...

 

[hiral.kotak]

lvt svt

Hi,

The basic explanation of the different vt cells is good.
So, if you are using a multivt library for your design implementation, you can choose the appropriate vt cells as per whether the design is timing critical or power critical. It is better to use low vt cells for timing critical path and high vt cells for non-timing critical path so that power target can be achieved.

Moreover for a low power desig you can apply the multivdd concept, diferent voltage domains and use of power gating.

It may help you.

Thanks..

HAK..

 

[nozone]

lvt hvt

usually you can first synthesis with only the low Vt cells, then optimize it, it will replace some of the non-critical cells with high Vt cells so that it can reduce the leakage power, and meet the timing requirement at the same time.

 

[sahana]

hvt lvt

Thanks for ur replies, even i too know the same things, but i expect some what more in details other than these.



sahana

 

[ramana459]

hvt svt lvt

Which technology you are using, better to raise Cadence Service Request, they will give the solution,

 

[sahana]

svt lvt

ya, Iam working on 90nm.

 

[ramana459]

svt hvt lvt

in gpdk 90nm tech we will find out only normal vt cells and Hvt cells.
for low vt cells you should take tech files from Foundries.