Power OpAmp Output Buffer - BiCMOS

hmmm do u think than in lov voltage an mosfets would be better option than bjt ??? I have in mind one not so good for lov volt apps bjt feature of constant rather high saturation voltage that develop in high current amps and such voltage is damn fairly high loss if u have only 12 volt available. More a magnitude of this voltage is dependent on log function of current conduced by bjt transistor so is fairly not a well linear also. Means that our power transistor behave as highly nonlinear zener diode. And when output current ie. swings from 1A to 15A (and in 12v circuits is a must when a reasonable power need to be delivered) this voltage can vary in magnitude even more than 2 volts so it,s fairly high loss and great ammount of distortion introduced. MosFets are far different cuz they behave as variable resistors not as diodes like bjt's and voltage on them depeends almost fully on channel resistance wich is set by gate voltage and is almost constant no matter how high current is. And as lov voltage mos transistor having a 20mOhm full on resistance rated specs are coommon this days such loses simply do not exist and linearity is far more better (a little distortions can occur only from channel lenght modulation but are so tiny that can be frequently ignored) i think that rather opposite statement should be consider a mosfet should be used in lov voltage power stages and bjt are far more better in high voltage apps where constant voltage drop of high voltage rated devices is almost the same as in lover voltage models. Instead mosfets to be able maintain high drain-source voltage must drasticly increase channel lenght and such operation increase fulll on resistance by extraordinary large value not saying of nonlinearity increasing due to also highly rised channel lenght modulation phenomenon.

Happy holiday to u also :-) I read the article and i tell u that i'v been unaware that this particular emi problem in lov power devices can be solved using bjt's. So it's reasonable to me now that not only chopper power supplies but also amplifiers wich those days are mainly created as switching amps of class D or T due to efficiency. As for deffend my statements only one argument i have left. A linear A, AB or B classes. When u are forced to use lov voltages such as in fancy high-end class B car amps (i see even class A car amp but ths is freaky idea to implement such lossy heavy amp in noisy car envi. where u simply can't hear undistorted music due to for example engine noise wich can't be lovered to zero due to car safety reasons) in such designs any volt of achievable voltage is in great worth. and during swings of output wave losing this precious volt not by dissipating it on modulating this wave transistor transresistance or on load but on unproductible CE junction is unacteptable.