Download ECE51602012springfinals

ECE 5160 Electromagnetic Effects in Integrated Circuits: Name:____________________
Show all your work.
I a) Explain with diagram the concept of differential signaling. What is the advantages and disadvantages
of differential signaling over single ended.
b) 1) For the differential transmission line shown in the figure below, determine the common mode
voltage due to ACCM for the following transmission line at 5 GHz.
Driver
l1=0.254 meters , r= 4.0
Reciever
l2=0.260 meters, r= 4.0
2) Determine the frequency at which all the differential voltage is converted to common mode voltage.
3) Determine the ACCM if the line 1 is under a dielectric constant of 3.5 and the other at dielectric
constant of 4.
4) The Differential traces on a BGA package has the shape shown in the following figure. Do you
anticipate any problem with this? If there is a problem, how you are going to correct it.
II. 1) Explain with diagram, what are effects of non-ideal return path on signal integrity.
How can you improve the signal integrity.
2) What is the effect on cross talk if signals routed on slots in the reference planes.
3) For the figure shown below, plot the TDR response as observed at point A.
Also determine
a)
b)
c)
d)
Current driving the transmission line.
Current in the gap.
Amplitude of the spike as observed in TDR.
Ledge in the receiver waveform.
C=1 nF
C= 1nF
III. a) What is the effect of plating roughness on the signal transmission characteristics for a transmission
line in a PCB. At what frequency, this effect becomes dominant.
b) Explain with diagram the fiber weave effect . How can you minimize the fiber weave effect
c) How environmental effect the transmission line performance in PCB and how can you minimize it.
e) Give the model of a lossy transmission line with conductor loss and dielectric loss.
f)
Calculate the output voltage at frequency 3GHz and 4 GHz at the output of a 0.5m transmission line
that is perfectly terminated in its characteristic impedance with the following properties:
Lext = 2.5x10-7H/m, Cquasistatic = 1.5x10-10-7F/m,
Electrical conductivity= 5.8x107S/m, Magnetic permeability=4px10-7H/m, width=100microns,
effective dielectric constant =3.32 at 1GHz with tand=0.0205 at 1 GHz.
IV. a) Give the circuit diagram of a push-pull transmitter. How can you improve the linearity of pushpull transmitters.
b) Give the circuit architecture of a receiver with ESD protection circuit. What is the effect of ESD
protection circuit on the performance of the receiver.
c) What are IBIS models for trans-recievers?
d) What are the Bergeron diagrams? Draw the Bergeron diagram at the source end and load end for a
transmitter with a voltage source 0 to 2.5V and edge rate 100ps and a series resistance 12.5 ohm. The
impedance of transmission line is 50 ohms and the transit time is 3 nano seconds. The termination
resistor at the receiver end is 75 ohms.