All RF Cafe quizzes make great fodder
employment interviews for technicians or engineers - particularly those who are fresh
out of school or are relatively new to the work world. Come to think of it, they would
make equally excellent study material for the same persons who are going to be interviewed
for a job.
Click here for the complete list of
RF Cafe Quizzes.
Note: Some material based on books have quoted passages.
is based on the information presented in Substrate Noise Coupling in Analog/RF Circuits,
by Stephane Bronkers, Geert Van der Plas, Gerd Vandersteen, and Yves Rolain. Published
by Artech House.
Note: Some of these books are available as
prizes in the monthly RF
1. Which is NOT a class of substrate noise analysis?
2. What is the most popular and straightforward method for
shielding analog integrated circuits
a) Ground plane
b) Guard rings
c) Copper conductors
3. Aggressor and victim refer to what process?
a) The design process and engineer doing the design, respectively
The source of and recipient of substrate noise, respectively
c) Hole and electron
d) Conductor and insulator substrate noise, respectively
4. What is the best way to separate substrate coupling noise
from other regional noise coupling
sources when developing
mixed (digital/analog) signal devices?
a) Dice between the regions to physically separate the digital/analog regions,
then wire bond between
b) Process a neutral region between digital / analog
regions, then wire bond between
c) Process a solid vertical metal wall between
digital/analog regions, then wire bond between
d) There is no method for totally
separating substrate noise between regions
5. At high frequencies, which off-chip noise coupling mechanism
a) Capacitive coupling between PCB traces
b) Inductive coupling between
c) Resistive coupling between the PCB and the die
coupling between die bond wires
6. What is the primary source of FM modulated noise spurs?
a) Doping impurities
b) Heavy p-type doping
on the ground interconnect
d) Low resistivity passivation
7. In a VCO circuit, what is a likely mechanism for AM spur
generation and intermediate frequencies?
a) Capacitive coupling from on-chip inductors to the substrate
coupling from on-chip inductors to the substrate
c) Magnetic coupling from on-chip
inductors to the substrate
d) Resistive coupling from on-chip inductors to the
8. How are digital and analog grounds kept separate on the
a) Integrate large resistors between digital / analog regions
large inductors between digital / analog regions
c) There is no effective method
for separating digital / analog grounds
d) Separate digital / analog ground
metal on the die, with separate off-chip digital / analog grounding points
9. For what purpose is parasitic extraction used?
a) Obtaining parasitic current / voltage values for use in production testing
b) Obtaining parasitic RLC values for publication in user datasheets
Obtaining parasitic RLC values for use in simulation
d) Obtaining parasitic
current / voltage values for use in simulation
10. What determines to a large extent the efficiency of a P+
a) Impedance of the ground interconnect
b) P-type doping density
c) Passivation purity
d) Voltage filtering
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answers and explanations.