EE130 Project | ||||||
Spring 2007 |
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Assignment
(due 4/27/07) 4/14/07 Update (provides helpful information) -- updated 4/22/07 For the calculation of cutoff
frequency fT, you
should use the
value of emitter-junction depletion capacitance (CdBE) that corresponds
to the base-emitter bias VBE
that yields
IC = 1mA.
Use the equilibrium value of collector-junction depletion capacitance (CdBC), which corresponds
to the edge of saturation (VBC
= 0V).
Note that
your BJT design should meet the stated specifications to within 5% over the specified
range of operating temperatures and with ±5%
variation in either
the base width or the base doping. For example, this means that
beta can be as
low as 0.95x45 = 42.75. (beta should be at least 45 at T = 300K for your nominal
design, however.)
Note that amount of band-gap narrowing in the emitter is dependent on the total dopant concentration (not the net dopant concentration). For the calculation of cutoff frequency fT, you should use the value of emitter-junction depletion capacitance (CdBE) that corresponds to the base-emitter bias VBE that yields IC = 1mA. Use the equilibrium value of collector-junction depletion capacitance (CdBC), which corresponds to the edge of saturation (VBC = 0V). Excerpts from MEDICI manual:
MEDICI:
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