CHAPTER 7 MODEL OF DIGITAL IC DESIGN

An NMOS transistor turns on when

• The gate is at logic 0 (GND)
• The gate is at logic 1 (V_DD)
• The drain is at logic 0 (GND)
• The drain is at logic 1 (V_DD)

A PMOS transistor turns on when

• The gate is at logic 1 (V_DD)
• The gate is at logic 0 (GND)
• The drain is at logic 0 (GND)
• The drain is at logic 1 (V_DD)

Miller capacitance is

• Capacitance between gate and source
• Capacitance between gate and drain
• Capacitance between gate and body
• Capacitance between source and drain

How does Miller capacitance affect MOSFET operation?

• Increases switching speed
• Decreases switching speed
• Does not affect switching speed
• Stabilizes output voltage

The effective capacitance of a MOSFET during switching is

• Equal to gate-to-drain capacitance
• Equal to gate-to-source capacitance
• Twice the gate-to-drain capacitance
• Twice the gate-to-source capacitance

The effective switching resistance of a long-channel MOSFET is determined by

• Resistance between gate and drain
• Resistance between gate and source
• Resistance between source and drain
• Resistance between gate and substrate

The effective switching resistance of a short-channel MOSFET depends on

• Channel length
• Channel width
• On-state current (I_on)
• Both channel length and width

When V_GS > V_DD/2, the MOSFET will

• Turn on
• Turn off
• Operate unstably
• Remain unchanged

The characteristic switching time constant (Ï„_n) is determined by

• R_n and C_ox
• V_GS and V_DD
• Resistance and capacitance between gate and source
• Channel length and width

The effective switching resistance of a PMOS is greater than that of an NMOS due to

• Higher intrinsic resistance
• Higher hole mobility
• Higher electron mobility
• Smaller size