75 lines
3.2 KiB
Markdown
75 lines
3.2 KiB
Markdown
E6E Semiconductor materials and packages for RF use
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- [[E6E01]] (B)
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Why is gallium arsenide (GaAs) useful for semiconductor devices operating at UHF and higher frequencies? #card
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- [[A.]] Higher noise figures
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- [[B.]] Higher electron mobility
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- [[C.]] Lower junction voltage drop
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- [[D.]] Lower transconductance
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- [[E6E02]] (A)
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Which of the following device packages is a through-hole type? #card
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- [[A.]] DIP
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- [[B.]] PLCC
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- [[C.]] BGA
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- [[D.]] SOT
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- [[E6E03]] (D)
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Which of the following materials supports the highest frequency of operation when used in MMICs? #card
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- [[A.]] Silicon
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- [[B.]] Silicon nitride
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- [[C.]] Silicon dioxide
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- [[D.]] Gallium nitride
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- [[E6E04]] (A)
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Which is the most common input and output impedance of MMICs? #card
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- [[A.]] 50 ohms
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- [[B.]] 300 ohms
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- [[C.]] 450 ohms
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- [[D.]] 75 ohms
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- [[E6E05]] (A)
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Which of the following noise figure values is typical of a low-noise UHF preamplifier? #card
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- [[A.]] 0.5 dB
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- [[B.]] -10 dB
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- [[C.]] 44 dBm
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- [[D.]] -20 dBm
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- [[E6E06]] (D)
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What characteristics of MMICs make them a popular choice for VHF through microwave circuits? #card
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- [[A.]] The ability to retrieve information from a single signal, even in the presence of other strong signals
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- [[B.]] Extremely high Q factor and high stability over a wide temperature range
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- [[C.]] Nearly infinite gain, very high input impedance, and very low output impedance
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- [[D.]] Controlled gain, low noise figure, and constant input and output impedance over the specified frequency range
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- [[E6E07]] (D)
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What type of transmission line is often used for connections to MMICs? #card
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- [[A.]] Miniature coax
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- [[B.]] Circular waveguide
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- [[C.]] Parallel wire
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- [[D.]] Microstrip
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- [[E6E08]] (C)
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How is power supplied to the most common type of MMIC? #card
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- [[A.]] Through a capacitor and RF choke connected to the amplifier input lead
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- [[B.]] MMICs require no operating bias
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- [[C.]] Through a resistor and/or RF choke connected to the amplifier output lead
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- [[D.]] Directly to the bias voltage (Vcc) lead
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- [[E6E09]] (D)
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Which of the following component package types have the least parasitic effects at frequencies above the HF range? #card
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- [[A.]] TO-220
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- [[B.]] Axial lead
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- [[C.]] Radial lead
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- [[D.]] Surface mount
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- [[E6E10]] (D)
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What advantage does surface-mount technology offer at RF compared to using through-hole components? #card
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- [[A.]] Smaller circuit area
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- [[B.]] Shorter circuit board traces
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- [[C.]] Components have less parasitic inductance and capacitance
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- [[D.]] All these choices are correct
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- [[E6E11]] (D)
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What is a characteristic of DIP packaging used for integrated circuits? #card
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- [[A.]] Extremely low stray capacitance (dielectrically isolated package)
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- [[B.]] Extremely high resistance between pins (doubly insulated package)
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- [[C.]] Two chips in each package (dual in package)
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- [[D.]] Two rows of connecting pins on opposite sides of package (dual in-line package)
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- [[E6E12]] (C)
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Why are DIP through-hole package ICs not typically used at UHF and higher frequencies? #card
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- [[A.]] Excessive dielectric loss
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- [[B.]] Epoxy coating is conductive above 300 MHz
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- [[C.]] Excessive lead length
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- [[D.]] Unsuitable for combining analog and digital signals
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