Logic Families and Their Characteristics MCQs

Question 1

How does the 4000 series of CMOS logic compare in terms of speed and power dissipation to the standard family of TTL logic?

Accepted Answer

less power dissipation and slower speed

Answer

more power dissipation and slower speed

Answer

more power dissipation and faster speed

Answer

less power dissipation and faster speed

Question 2

When the outputs of several open-collector TTL gates are connected together, the gate outputs ________.

Accepted Answer

are ANDed together

Answer

usually burn out

Answer

produce more voltage

Answer

produce more fan-out

Question 3

Propagation delay is important because ________.

Accepted Answer

the logic gates must be given a short break during each clock cycle or else they will overheat

Answer

it limits the maximum operating frequency of a gate

Answer

it is a measure of how long the clock must be applied to the gate before it will make the required decision

Answer

all the gates in a system must have the same propagation times in order to be compatible

Question 4

________ output levels would not be a valid LOW for a TTL gate.

Accepted Answer

All of the above.

Answer

0.2 V

Answer

0.3 V

Answer

0.5 V

Question 5

The minimum input voltage recognized as HIGH by a TTL gate is ________.

Accepted Answer

2.0 V

Answer

2.4 V

Answer

0.8 V

Answer

5.0 V

Question 6

Several manufacturers have developed logic that combines the best features of TTL and CMOS. This is called ________.

Accepted Answer

BiCMOS

Answer

12L

Answer

74ACT

Answer

74HCT

Question 7

Totem-pole outputs ________ be connected ________ because ________.

Accepted Answer

cannot, together, if the outputs are in opposite states excessively high currents can damage one or both of the devices

Answer

can, in parallel, sometimes higher output current is required

Answer

should, in series, certain applications may require higher output voltage

Answer

can, together, together they can handle larger load currents and higher output voltages

Question 8

The power dissipation of a CMOS IC will ________.

Accepted Answer

increase with frequency

Answer

decrease with frequency

Answer

increase with gate size

Answer

decrease with gate size

Question 9

When VGS = 0 on an N-channel MOSFET switch, there is no ________ between the source and the drain.

Accepted Answer

conductive channel

Answer

voltage drop

Answer

capacitance

Answer

inductance