density rule in cmos fab
Bipolar vs. CMOS (performance)
Compared to CMOS, bipolar transistors
o have lower parametric variance
o can operate with higher supply voltages
o have higher device gain (higher rout)
o can operate with higher output current density, and thus lower
o parasitic capacitance for a given current
o maintain current gain over decades of collector current
Therefore, compared to CMOS, bipolar amplifiers
o have lower untrimmed offset
o support higher voltage swings
o can drive resistive loads with higher bandwidth