Hi,
Thanks for writing in. This in the 1st time would have been more helpful, was happy to see a moderator answer me. And yeah it was naive of me to ignore the SCNR remark :bang:
I do not say i know a lot, just learning, and thanks for the patience to point out the threads and articles. However, i think i know the meaning the liberty quite well. You dont need a dictionary to find a VLSI terminology. Anyways, please refer to this link :
https://www.csee.umbc.edu/~cpatel2/links/641/slides/lect05_LIB.pdf
The liberty does have k-factors and it is used for scaling it or 'derating' the values of transition. setup etc..
This part is clear to me.
My question was entirely different and yeah i am not claiming i always ask the right thing but i would prefer a SCNR with a proper answer.
Thanks for your time and the links.
Given the fact that derating is mentioned whereever you find reference to k-factors it is quite obvious to get confused but there is quite a lot of difference between k-factors and derating factors used for AOCVM.
If you open your.lib (or LIBERTY) :grin: then you will find something called nominal operating conditions. These are the PVT conditions on which the lib has been characterized, say Pslow, V90, T100 but now suppose inside your dsign you specify an operating condition as Pslow,V95,T110 then this differes from the characterized values. So your values in the .lib have to be scaled to bring it upto the mark of the operating condition, say if some transition time was 20 then for more Voltage it should be more (ideally) so it is multiplied with a k-factor (say 0.25) then it becomes 20+20*0.25 = 25 (just for example) This is k-factor scaling but nowadays since we use MCMM we prefer to supply the tool link libraries for every operating condition. So, the k-factors nowadays is 0, however major tool makers have decided to include interpolation in MCMM too.
.
About derating in OCV -> Say your operating condition is Pslow,V90,T100 and you have the link library for this but to do OCV i.e add extra pessissism you will multiply a factor to increase the delay in launch path and reduce it in capture path (setup) . This is multiplied to al the delays.
Now understand tis that OCV will be added on top of k-factors if different set of operating conditions are used and if the library uses interpolation but because we do not use k-factors now-a-days so only OCV derating factor comes into picture.
Hope it helps.
Thanks,
ro9ty
- - - Updated - - -
Hi,
Thanks for writing in. This in the 1st time would have been more helpful, was happy to see a moderator answer me. And yeah it was naive of me to ignore the SCNR remark :bang:
I do not say i know a lot, just learning, and thanks for the patience to point out the threads and articles. However, i think i know the meaning the liberty quite well. You dont need a dictionary to find a VLSI terminology. Anyways, please refer to this link :
https://www.csee.umbc.edu/~cpatel2/links/641/slides/lect05_LIB.pdf
The liberty does have k-factors and it is used for scaling it or 'derating' the values of transition. setup etc..
This part is clear to me.
My question was entirely different and yeah i am not claiming i always ask the right thing but i would prefer a SCNR with a proper answer.
Thanks for your time and the links.
Given the fact that derating is mentioned whereever you find reference to k-factors it is quite obvious to get confused but there is quite a lot of difference between k-factors and derating factors used for AOCVM.
If you open your.lib (or LIBERTY) :grin: then you will find something called nominal operating conditions. These are the PVT conditions on which the lib has been characterized, say Pslow, V90, T100 but now suppose inside your dsign you specify an operating condition as Pslow,V95,T110 then this differes from the characterized values. So your values in the .lib have to be scaled to bring it upto the mark of the operating condition, say if some transition time was 20 then for more Voltage it should be more (ideally) so it is multiplied with a k-factor (say 0.25) then it becomes 20+20*0.25 = 25 (just for example) This is k-factor scaling but nowadays since we use MCMM we prefer to supply the tool link libraries for every operating condition. So, the k-factors nowadays is 0, however major tool makers have decided to include interpolation in MCMM too.
.
About derating in OCV -> Say your operating condition is Pslow,V90,T100 and you have the link library for this but to do OCV i.e add extra pessissism you will multiply a factor to increase the delay in launch path and reduce it in capture path (setup) . This is multiplied to al the delays.
Now understand tis that OCV will be added on top of k-factors if different set of operating conditions are used and if the library uses interpolation but because we do not use k-factors now-a-days so only OCV derating factor comes into picture.
Hope it helps.
Thanks,
ro9ty
- - - Updated - - -
Hi,
Thanks for writing in. This in the 1st time would have been more helpful, was happy to see a moderator answer me. And yeah it was naive of me to ignore the SCNR remark :bang:
I do not say i know a lot, just learning, and thanks for the patience to point out the threads and articles. However, i think i know the meaning the liberty quite well. You dont need a dictionary to find a VLSI terminology. Anyways, please refer to this link :
https://www.csee.umbc.edu/~cpatel2/links/641/slides/lect05_LIB.pdf
The liberty does have k-factors and it is used for scaling it or 'derating' the values of transition. setup etc..
This part is clear to me.
My question was entirely different and yeah i am not claiming i always ask the right thing but i would prefer a SCNR with a proper answer.
Thanks for your time and the links.
Given the fact that derating is mentioned whereever you find reference to k-factors it is quite obvious to get confused but there is quite a lot of difference between k-factors and derating factors used for AOCVM.
If you open your.lib (or LIBERTY) :grin: then you will find something called nominal operating conditions. These are the PVT conditions on which the lib has been characterized, say Pslow, V90, T100 but now suppose inside your dsign you specify an operating condition as Pslow,V95,T110 then this differes from the characterized values. So your values in the .lib have to be scaled to bring it upto the mark of the operating condition, say if some transition time was 20 then for more Voltage it should be more (ideally) so it is multiplied with a k-factor (say 0.25) then it becomes 20+20*0.25 = 25 (just for example) This is k-factor scaling but nowadays since we use MCMM we prefer to supply the tool link libraries for every operating condition. So, the k-factors nowadays is 0, however major tool makers have decided to include interpolation in MCMM too.
.
About derating in OCV -> Say your operating condition is Pslow,V90,T100 and you have the link library for this but to do OCV i.e add extra pessissism you will multiply a factor to increase the delay in launch path and reduce it in capture path (setup) . This is multiplied to al the delays.
Now understand tis that OCV will be added on top of k-factors if different set of operating conditions are used and if the library uses interpolation but because we do not use k-factors now-a-days so only OCV derating factor comes into picture.
Hope it helps.
Thanks,
ro9ty
- - - Updated - - -
Hi,
Thanks for writing in. This in the 1st time would have been more helpful, was happy to see a moderator answer me. And yeah it was naive of me to ignore the SCNR remark :bang:
I do not say i know a lot, just learning, and thanks for the patience to point out the threads and articles. However, i think i know the meaning the liberty quite well. You dont need a dictionary to find a VLSI terminology. Anyways, please refer to this link :
https://www.csee.umbc.edu/~cpatel2/links/641/slides/lect05_LIB.pdf
The liberty does have k-factors and it is used for scaling it or 'derating' the values of transition. setup etc..
This part is clear to me.
My question was entirely different and yeah i am not claiming i always ask the right thing but i would prefer a SCNR with a proper answer.
Thanks for your time and the links.
Given the fact that derating is mentioned whereever you find reference to k-factors it is quite obvious to get confused but there is quite a lot of difference between k-factors and derating factors used for AOCVM.
If you open your.lib (or LIBERTY) :grin: then you will find something called nominal operating conditions. These are the PVT conditions on which the lib has been characterized, say Pslow, V90, T100 but now suppose inside your dsign you specify an operating condition as Pslow,V95,T110 then this differes from the characterized values. So your values in the .lib have to be scaled to bring it upto the mark of the operating condition, say if some transition time was 20 then for more Voltage it should be more (ideally) so it is multiplied with a k-factor (say 0.25) then it becomes 20+20*0.25 = 25 (just for example) This is k-factor scaling but nowadays since we use MCMM we prefer to supply the tool link libraries for every operating condition. So, the k-factors nowadays is 0, however major tool makers have decided to include interpolation in MCMM too.
.
About derating in OCV -> Say your operating condition is Pslow,V90,T100 and you have the link library for this but to do OCV i.e add extra pessissism you will multiply a factor to increase the delay in launch path and reduce it in capture path (setup) . This is multiplied to al the delays.
Now understand tis that OCV will be added on top of k-factors if different set of operating conditions are used and if the library uses interpolation but because we do not use k-factors now-a-days so only OCV derating factor comes into picture.
Hope it helps.
Thanks,
ro9ty
- - - Updated - - -
Hi,
Thanks for writing in. This in the 1st time would have been more helpful, was happy to see a moderator answer me. And yeah it was naive of me to ignore the SCNR remark :bang:
I do not say i know a lot, just learning, and thanks for the patience to point out the threads and articles. However, i think i know the meaning the liberty quite well. You dont need a dictionary to find a VLSI terminology. Anyways, please refer to this link :
https://www.csee.umbc.edu/~cpatel2/links/641/slides/lect05_LIB.pdf
The liberty does have k-factors and it is used for scaling it or 'derating' the values of transition. setup etc..
This part is clear to me.
My question was entirely different and yeah i am not claiming i always ask the right thing but i would prefer a SCNR with a proper answer.
Thanks for your time and the links.
Given the fact that derating is mentioned whereever you find reference to k-factors it is quite obvious to get confused but there is quite a lot of difference between k-factors and derating factors used for AOCVM.
If you open your.lib (or LIBERTY) :grin: then you will find something called nominal operating conditions. These are the PVT conditions on which the lib has been characterized, say Pslow, V90, T100 but now suppose inside your dsign you specify an operating condition as Pslow,V95,T110 then this differes from the characterized values. So your values in the .lib have to be scaled to bring it upto the mark of the operating condition, say if some transition time was 20 then for more Voltage it should be more (ideally) so it is multiplied with a k-factor (say 0.25) then it becomes 20+20*0.25 = 25 (just for example) This is k-factor scaling but nowadays since we use MCMM we prefer to supply the tool link libraries for every operating condition. So, the k-factors nowadays is 0, however major tool makers have decided to include interpolation in MCMM too.
.
About derating in OCV -> Say your operating condition is Pslow,V90,T100 and you have the link library for this but to do OCV i.e add extra pessissism you will multiply a factor to increase the delay in launch path and reduce it in capture path (setup) . This is multiplied to al the delays.
Now understand tis that OCV will be added on top of k-factors if different set of operating conditions are used and if the library uses interpolation but because we do not use k-factors now-a-days so only OCV derating factor comes into picture.
Hope it helps.
Thanks,
ro9ty