assignment4

# Assignment4 - Ccbx Rbb ECE145C/218C PS 4 Above is a device model Recall that C be = C be,depl g m f Let us take Cje=32 fF beta=50 Ccbi=2.2 fF

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1 cbi C bb R be C ' ' e b m V g be R ex R + - ' ' e b V cbx C ECE145C/218C PS 4. Above is a device model . Recall that f m depl be be g C C τ + = , . Let us take Cje=32 fF, beta=50, Ccbi=2.2 fF, Ccbx=6.0 fF, Rbb=38 Ohms, Rex=2.8Ohms, and tau_f=0.28 ps. Lets use this device model in circuit calculations below. The transistor, incidentally, has Ae=0.6 um x 4.3 um emitter area, has a peak 450 GHz ft and 490 GHz fmax, operates at a maximum of 12 mA/um^2 at Vce=0.7 volts. For the purpose of this problem set only, to simplify the calculations, let us move all the collector-base capacitance inside Rbb, eg change Ccbi to 8.2 fF, and set Ccbx to 0 fF More details --though not needed for this problem set-- regarding this transistor can be found at http://www.ece.ucsb.edu/Faculty/rodwell/Downloads/Publications/Griffith_DRC2005_digest.pdf Ree Rcs Ree RL RL RL RL Problem 1: The circuit to the left is one stage in a string of identical differential stages. The positive supply is zero volts and the negative

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## This note was uploaded on 08/06/2008 for the course ECE 145 taught by Professor Rodwell during the Fall '07 term at UCSB.

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Assignment4 - Ccbx Rbb ECE145C/218C PS 4 Above is a device model Recall that C be = C be,depl g m f Let us take Cje=32 fF beta=50 Ccbi=2.2 fF

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