Q.1

Why is a decoupling capacitor needed for TTL ICs and where should it be connected?

  • to block dc, connect to input pins
  • to reduce noise, connect to input pins
  • to reduce the effects of noise, connect between power supply and ground
Q.2

How can ECL have both a NOR and an OR output?

  • ECL does not have this feature.
  • They are simply the inverse of each other.
Q.3

The high input impedance of MOSFETs:

  • allows faster switching
  • reduces input current and power dissipation
  • prevents dense packing
  • creates low-noise reactions
Q.4

The output current capability of a single 7400 NAND gate when HIGH is called ________.

  • source current
  • sink current
  • IOH
  • source current of IOH
Q.5

The TTL HIGH level source current is higher than the LOW level sinking current.

  • True
  • False
Q.6

The most common TTL series ICs are:

  • E-MOSFET
  • 7400
  • quad
  • AC00
Q.7

Ten TTL loads per TTL driver is known as:

  • noise immunity
  • fan-out
  • power dissipation
  • propagation delay
Q.8

The word "interfacing" as applied to digital electronics usually means:

  • a conditioning circuit connected between a standard TTL NAND gate and a standard TTL OR gate
  • a circuit connected between the driver and load to condition a signal so that it is compatible with the load
  • any gate that is a TTL operational amplifier designed to condition signals between NMOS transistors
  • any TTL circuit that is an input buffer stage
Q.9

Using the schematic diagram of a TTL NAND gate, determine the state of each transistor (ON or OFF) when all inputs are high.

  • Q1-ON, Q2-OFF, Q3-ON, Q4-OFF
  • Q1-ON, Q2-ON, Q3-OFF, Q4-OFF
  • Q1-OFF, Q2-OFF, Q3-ON, Q4-ON
  • Q1-OFF, Q2-ON, Q3-OFF, Q4-ON
Q.10

Which logic family is characterized by a multiemitter transistor on the input?

  • ECL
  • CMOS
  • TTL
  • None of the above
Q.11

The time needed for an output to change from the result of an input change is known as:

  • noise immunity
  • fan-out
  • propagation delay
  • rise time
Q.12

The problem of different current requirements when CMOS logic circuits are driving TTL logic circuits can usually be overcome by the addition of:

  • a CMOS inverting bilateral switch between the stages
  • a TTL tristate inverting buffer between the stages
  • a CMOS noninverting bilateral switch between the stages
  • a CMOS buffer or inverting buffer
Q.13

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.

  • 10%, 90%, 90%, 10%
  • 90%, 10%, 10%, 90%
  • 20%, 80%, 80%, 20%
  • 10%, 70.7%, 70.7%, 10%
Q.14

If all inputs to a TTL NAND gate are low, what is the ON, OFF condition of each transistor in the circuit?

  • Q1-ON, Q2-OFF, Q3-ON, Q4-OFF
  • Q1-ON, Q2-ON, Q3-OFF, Q4-OFF
  • Q1-OFF, Q2-OFF, Q3-ON, Q4-ON
  • Q1-OFF, Q2-ON, Q3-OFF, Q4-ON
Q.15

The problem of the VOH(min) of a TTL IC being too low to drive a CMOS circuit and meet the CMOS requirement of VIH(min) is usually easily overcome by:

  • adding a fixed voltage-divider bias resistive network at the output of the TTL device
  • avoiding this condition and only using TTL to drive TTL
  • adding an external pull-down resistor to ground
  • adding an external pull-up resistor to VCC
Q.16

The problem of interfacing IC logic families that have different supply voltages (VCC's) can be solved by using a:

  • level-shifter
  • tristate shifter
  • decoupling capacitor
  • pull-down resistor
Q.17

The problem of the VOH(min) of a TTL IC being too low to drive a CMOS circuit and meet the CMOS requirement of VIH(min) is usually easily overcome by:

  • adding a fixed voltage-divider bias resistive network at the output of the TTL device
  • avoiding this condition and only using TTL to drive TTL
  • adding an external pull-down resistor to ground
  • adding an external pull-up resistor to VCC
Q.18

Fan-out is determined by taking the ________ result(s) of ________.

  • smaller,
  • larger,
  • smaller,
  • average,
Q.19

Which family of devices has the characteristic of preventing saturation during operation?

  • TTL
  • MOS
  • ECL
  • IIL
Q.20

What is unique about TTL devices such as the 74SXX?

  • These devices use Schottky transistors and diodes to prevent them from going into saturation; this results in faster turn-on and turn-off times, which translates into higher frequency operation.
  • The gate transistors are silicon (S), and the gates therefore have lower values of leakage current.
  • The S denotes the fact that a single gate is present in the IC rather than the usual package of 2–6 gates.
  • The S denotes a slow version of the device, which is a consequence of its higher power rating.
0 h : 0 m : 1 s