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Home Digital Electronics Logic Families and Their Characteristics Comments

  • Question
  • 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:


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

  • Correct Answer
  • adding an external pull-up resistor to VCC 


  • Logic Families and Their Characteristics problems


    Search Results


    • 1. PMOS and NMOS ________.

    • Options
    • 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
    • Discuss
    • 2. Which of the following logic families has the shortest propagation delay?

    • Options
    • A. CMOS
    • B. BiCMOS
    • C. ECL
    • D. 74SXX
    • Discuss
    • 3. Why is the operating frequency for CMOS devices critical for determining power dissipation?

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

    • Options
    • A. level-shifter
    • B. tristate shifter
    • C. decoupling capacitor
    • D. pull-down resistor
    • Discuss
    • 5. Which is a mode of operation of the GAL16V8?

    • Options
    • A. Simple mode
    • B. Complex mode
    • C. Registered mode
    • D. All of the above
    • Discuss
    • 6. Which family of devices has the characteristic of preventing saturation during operation?

    • Options
    • A. TTL
    • B. MOS
    • C. ECL
    • D. IIL
    • Discuss
    • 7. Which of the following summarizes the important features of emitter-coupled logic (ECL)?

    • Options
    • A. low noise margin, low output voltage swing, negative voltage operation, fast, and high power consumption
    • B. good noise immunity, negative logic, high-frequency capability, low power dissipation, and short propagation time
    • C. low propagation time, high-frequency response, low power consumption, and high output voltage swings
    • D. poor noise immunity, positive supply voltage operation, good low-frequency operation, and low power
    • Discuss
    • 8. Why is a decoupling capacitor needed for TTL ICs and where should it be connected?

    • Options
    • A. to block dc, connect to input pins
    • B. to reduce noise, connect to input pins
    • C. to reduce the effects of noise, connect between power supply and ground
    • Discuss
    • 9. An open collector output can ________ current, but it cannot ________.

    • Options
    • A. sink, source current
    • B. source, sink current
    • C. sink, source voltage
    • D. source, sink voltage
    • Discuss
    • 10. The TTL HIGH level source current is higher than the LOW level sinking current.

    • Options
    • A. True
    • B. False
    • Discuss


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