Logic Families and Their Characteristcs Questions and Answers

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Showing 10 of 47 questions
Q21
The rise time (tr) is the time it takes for a pulse to rise from its ________ point up to its ________ point. The fall time (tf) is the length of time it takes to fall from the ________ to the ________ point.
  • A 10%, 90%, 90%, 10%
  • B 90%, 10%, 10%, 90%
  • C 20%, 80%, 80%, 20%
  • D 10%, 70.7%, 70.7%, 10%
Answer: Option A
Q22
The term buffer/driver signifies the ability to provide low output currents to drive light loads.
  • A TRUE
  • B FALSE
Answer: Option B
Q23
PMOS and NMOS ________.
  • A represent MOSFET devices utilizing either P-channel or N-channel devices exclusively within a given gate
  • B are enhancement-type CMOS devices used to produce a series of high-speed logic known as 74HC
  • C represent positive and negative MOS-type devices, which can be operated from differential power supplies and are compatible with operational amplifiers
  • D None of the above
Answer: Option A
Q24
Why is the operating frequency for CMOS devices critical for determining power dissipation?
  • A At low frequencies, power dissipation increases.
  • B At high frequencies, the gate will only be able to deliver 70.7 % of rated power.
  • C At high frequencies, charging and discharging the gate capacitance will draw a heavy current from the power supply and thus increase power dissipation.
  • D At high frequencies, the gate will only be able to deliver 70.7 % of rated power and charging and discharging the gate capacitance will draw a heavy current from the power supply and thus increase power dissipation.
Answer: Option C
Q25
Ten TTL loads per TTL driver is known as:
  • A noise immunity
  • B fan-out
  • C power dissipation
  • D propagation delay
Answer: Option B
Q26
The problem of different current requirements when CMOS logic circuits are driving TTL logic circuits can usually be overcome by the addition of:
  • A a CMOS inverting bilateral switch between the stages
  • B a TTL tristate inverting buffer between the stages
  • C a CMOS noninverting bilateral switch between the stages
  • D a CMOS buffer or inverting buffer
Answer: Option D
Q27
Totem-pole outputs ________ be connected ________ because ________.
  • A can, in parallel, sometimes higher current is required
  • B cannot, together, if the outputs are in opposite states excessively high currents can damage one or both devices
  • C should, in series, certain applications may require higher output voltage
  • D can, together, together they can handle larger load currents and higher output voltages
Answer: Option B
Q28
The high input impedance of MOSFETs:
  • A allows faster switching
  • B reduces input current and power dissipation
  • C prevents dense packing
  • D creates low-noise reactions
Answer: Option B
Q29
The output current capability of a single 7400 NAND gate when HIGH is called ________.
  • A source current
  • B sink current
  • C IOH
  • D source current of IOH
Answer: Option A
Q30
The time needed for an output to change from the result of an input change is known as:
  • A noise immunity
  • B fan-out
  • C propagation delay
  • D rise time
Answer: Option C

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