DharmaSlice
Member level 1
Hi,
Normally when I look at a PMOS current mirror with cascode they are sized with different lengths. As an example the PMOS current source could be 7.5u/3u (W/L) and the cascode set at 7.5/0.35.
During layout then it requires two seperate regions for the PMOS sources and cascode region. However, if the Lengths are made the same the layout can be built up from a unit cell containing a PMOS current source + cascode cell in the middle.
My question is: What are the negatives for increasing the cascode length from 0.35u to 3u ?
Thanks!
Normally when I look at a PMOS current mirror with cascode they are sized with different lengths. As an example the PMOS current source could be 7.5u/3u (W/L) and the cascode set at 7.5/0.35.
During layout then it requires two seperate regions for the PMOS sources and cascode region. However, if the Lengths are made the same the layout can be built up from a unit cell containing a PMOS current source + cascode cell in the middle.
My question is: What are the negatives for increasing the cascode length from 0.35u to 3u ?
Thanks!