Diode
Chapter 3, Digital Integrated Circuits, J. M. Rabaey
Note: For all problems, use the device parameters provided in Chapter 3 (Tables 3.2 and
3.5) and the inside back book cover, unless otherwise mentioned. Also assume T = 300 K
by default.
1)
a. Consider the circuit of Figure P1. Using the simple model, with VD-on = 0.7 V, solve
for ID.
b. Find ID and VD using the ideal diode equation. Use Is = 10–14 A and T = 300 K.
c. Repeat parts b using IS = 10–16 A, T = 300K, and IS = 10–14A, T = 350 K.
Figure P1
2)
For the circuit in Figure P2, Vs = 3.3 V. Assume AD = 12 µm2, φ0 = 0.65 V, and m = 0.5.
NA = 2.5 E16 and ND = 5 E15.
a. Find ID and VD.
b. Is the diode forward- or reverse-biased?
c. Find the depletion region width, Wj, of the diode.
d. Use the parallel-plate model to find the junction capacitance, Cj.
e. Set Vs = 1.5 V. Again using the parallel-plate model, explain qualitatively why Cj
increases.
Figure P2
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