contact.vincent
Newbie level 4
bjt problem solve
A silicon n+ - p - n transistor has abrupt dopings in both emitter and collector sides.
It has impurity concentrations 10^19, 3*10^16 and 5*10^15 cm^-3 in the emitter, base and collector respectively.
(a) Find the upper limit of the base-collector voltage at which the emitter bias can no longer control the collector current. Assume the base width is 0.5 micro meter.
(b) If the cutoff frequency is limited mainly by transit time of minority carriers across the base, find the common base and common emitter cutoff frequencies at zero bias.
The transistor has an emitter efficiency of 0.999, a base transport factor of 0.99 and Dn = 25 cm^2/sec
A silicon n+ - p - n transistor has abrupt dopings in both emitter and collector sides.
It has impurity concentrations 10^19, 3*10^16 and 5*10^15 cm^-3 in the emitter, base and collector respectively.
(a) Find the upper limit of the base-collector voltage at which the emitter bias can no longer control the collector current. Assume the base width is 0.5 micro meter.
(b) If the cutoff frequency is limited mainly by transit time of minority carriers across the base, find the common base and common emitter cutoff frequencies at zero bias.
The transistor has an emitter efficiency of 0.999, a base transport factor of 0.99 and Dn = 25 cm^2/sec