LEcture-1-and-2-Review-on-JFET-and-MOSFET-QUIZ1-Coverage_Student-Copy.pdf

Reviews of Transistor Devices Bipolar Junction Transistor (BJT) Devices Field Effect Transistor (FET) Devices Review on Bipolar Junction Transistor (BJT) Devices Review on Bipolar Junction Transistor (BJT) Devices Bipolar Transistor Construction Review on Field Effect Transistor (FET) Dev...

Reviews of Transistor Devices Bipolar Junction Transistor (BJT) Devices Field Effect Transistor (FET) Devices Review on Bipolar Junction Transistor (BJT) Devices Review on Bipolar Junction Transistor (BJT) Devices Bipolar Transistor Construction Review on Field Effect Transistor (FET) Devices Review on Field Effect Transistor (FET) Devices Field Effect Transistor (FET) Devices Field Effect Transistor (FET) Devices Field Effect Transistor (FET) Devices Field Effect Transistor (FET) Devices Field Effect Transistor (FET) Devices Field Effect Transistor (FET) Devices Field Effect Transistor (FET) Devices Field Effect Transistor (FET) Devices Field Effect Transistor (FET) Devices Field Effect Transistor (FET) Devices Field Effect Transistor (FET) Devices Field Effect Transistor (FET) Devices Field Effect Transistor (FET) Devices Field Effect Transistor (FET) Devices Field Effect Transistor (FET) Devices Field Effect Transistor (FET) Devices JFET Modes of Operation Common Source (CS) Configuration Most common modes of operation High input impedance High voltage gain Used in audio frequency amplifier Output signal 180o “out-of-phase” with the input JFET Modes of Operation Common Gate (CG) Configuration Input terminal: Source Output terminal: Drain Low input impedance High output impedance Used in high frequency and in impedance matching circuits Output signal 0o “In-phase” with the input JFET Modes of Operation Common Drain (CD) Configuration Input terminal: Gate Output terminal: Source High input impedance Low output impedance Near-unity voltage gain Used in buffer amplifiers, also called source follower Output signal 0o “In-phase” with the input Field Effect Transistor (FET) Biasing Field Effect Transistor (FET) Devices Field Effect Transistor (FET) Devices Field Effect Transistor (FET) Devices Field Effect Transistor (FET) Devices Field Effect Transistor (FET) Devices Field Effect Transistor (FET) Devices =Idss -Idss Field Effect Transistor (FET) Devices Field Effect Transistor (FET) Devices Field Effect Transistor (FET) Devices Field Effect Transistor (FET) Devices Field Effect Transistor (FET) Devices Field Effect Transistor (FET) Devices Field Effect Transistor (FET) Devices Field Effect Transistor (FET) Devices Field Effect Transistor (FET) Devices Field Effect Transistor (FET) Devices Transfer Characteristic curve and Drain curve for Common source JFET Amplifier Field Effect Transistor (FET) Devices IDSS = 5mA Vp = -5V MOSFET MOSFET stands for Metal Oxide Semiconductor Field Effect Transistor. It is a type of Field Effect Transistor and it is a voltage-controlled device. It is also called an Insulated Gate Field Effect Transistor (IGFET). It is used for switching or amplifying electronic signals in electronic devices. It is the most commonly used transistor and it can be used in both analog and digital circuits.  Difference between JFET and MOSFET Parameter JFET MOSFET JFET stands for Junction Field Effect MOSFET stands for Metal Oxide Full form Transistor. Semiconductor Field Effect Transistor. JFET is a three terminal device, where MOSFET is also a four terminal device, Terminals the terminals are named – Source (S), where the terminals are – Source (S), Drain Drain (D) and Gate (G). (D), Gate (G) and Body or Substrate (B). MOSFET can be operated in both Mode of operation JFET operates only in depletion mode. enhancement mode and depletion mode. JFET has a gate terminal which is not The gate terminal of the MOSFET is Gate terminal insulated from the channel. insulated from thin layer of metal-oxide. MOSFET has a continuous channel only in the depletion type, but not in the JFET has a continuous channel. The Channel enhancement type. Thus, the channel exists channel exists permanently. permanently in depletion type, but not in enhancement type.  Difference between JFET and MOSFET Parameter JFET MOSFET MOSFETs are of four types: P-channel enhancement MOSFET, P-channel JFETs are of two type: N-channel JFET Types depletion MOSFET, N-channel and P-channel JFET. enhancement MOSFET and N-channel depletion MOSFET. JFET has a high input impedance which is MOSFET has very high input impedance of Input impedance of the order of 109 Ω. the order of 1014 Ω. MOSFET is more susceptible to damage JFET is less susceptible to damage as it Susceptible to damage because the presence of metal oxide has high input capacitance. reduces input capacitance. The manufacturing process of JFET is Manufacturing process Manufacturing of MOSFET is complex. simple and less sophisticated. The drain resistance of JFET is high and The drain resistance of MOSFET is low of Drain resistance ranges from 105 Ω to 106 Ω. the order of 1 Ω to 50 Ω.  Difference between JFET and MOSFET Parameter JFET MOSFET The addition of metal oxide increases the The manufacturing cost of a JFET is less Manufacturing cost manufacturing cost of MOSFET. Thus, than MOSFET. MOSFET is expensive than JFET. In MOSFET, the Gate terminal is isolated In JFET, the Gate terminal is connected from the channel, and the voltage applied directly to the channel, and the voltage Gate terminal to the Gate terminal controls the current applied to the Gate terminal controls the flow, which creates an electric field across current flow. the oxide layer. MOSFET has relatively less flat Characteristics curve JFET has more flat characteristics curve. characteristics curve. In JFET, the conductivity of the device is In MOSFET, the conductivity is controlled Conductivity control controlled by the reverse biasing of the by the charge carriers induced in the gate. channel. MOSFET has more signal handling capacity Signal handling capacity The signal capacity of the JFET is less. than JFET. D-MOSFET Depletion Mode - Metal Oxide Semiconductor Field Effect Transistor N-Channel D-MOSFET Construction N-Channel D-MOSFET Construction Drain and Transfer Characteristics for n-channel D-MOSFET Transfer Characteristics Curve Drain Characteristics Curve P-Channel D-MOSFET Construction E-MOSFET Enhancement Mode - Metal Oxide Semiconductor Field Effect Transistor N-Channel E-MOSFET Construction N-channel E-MOSFET I-V Characteristics With a fixed VDS drain-source voltage connected across the EMOSFET, we can plot the values of drain current, ID with varying values of VGS to obtain a graph of the MOSFET’s forward DC characteristics. These characteristics give the transconductance, gm of the transistor. N-channel E-MOSFET I-V Characteristics This transconductance relates the output current to the input voltage representing the gain of the transistor. The slope of the transconductance curve at any point along it is therefore given as: gm = ID/VGS for a constant value of VDS. N-channel E-MOSFET I-V Characteristics Sample Problem. Assume a MOS transistor passes a drain current of 2mA when VGS = 3v and a drain current of 14mA when VGS = 7v. Determine the transconductance of the transistor.