In electronics, the metal–oxide–semiconductor field-effect transistor (MOSFET, MOS-FET, MOS FET, or MOS transistor) is a type of field-effect transistor (FET), most commonly fabricated by the controlled oxidation of silicon. It has an insulated gate, the voltage of which determines the conductivity of the device.

2005年10月18日 · • What is the topology of a small-signal equivalent cir-cuit model of the MOSFET? • What are the key dependencies of the leading model elements in saturation?

Today, millions of MOSFET transistors are integrated in modern electronic components, from microprocessors, through “discrete” power transistors. The focus of this topic is the gate drive requirements of the power MOSFET in various switch mode power conversion applications.

I. MOSFET Circuit Models A. Large Signal Model - NMOS • Cutoff: (VGS ≤ VTn)-----> ID = 0 • Triode: (VGS ≥ VTn and VDS ≤ VGS - VTn) • CLM term added to ensure continuous curve for ID vs. VDS • Saturation: (VGS ≥ VTn and VDS ≥ VGS - VTn). B. Backgate Effect • The threshold voltage is a function of the bulk-to-source voltage ...

l The fourth terminal of the MOSFET is the body of the transistor… it can act like a second gate, or “back gate” l The junctions of the transistor form pn-junction diodes with body, this introduces parasitic capacitance l Modern transistors are very short channel lengths, and there are many “short channel” effects that

MOSFET – Small Signal Model • To determine the small-signal performance of a given MOSFET amplifier circuit, we can replace the BJT with its small-signal model :

What is small-signal analysis? Small-signal models (cutoff/triode/active regions) −Transconductance, g m −Finite output impedance, r o −Standard model and T-model Small-signal analysis examples 26/26

• The MOSFET is usually smaller than the BJT. – It consumes less power. – It has a much smaller transconductance, g m, because of its small cross-sectional area. • Massive integration techniques for digital applications. • BJTs generally have better performance (predictable small signal parameters). • Modern digital very-large-scale ...

2024年1月14日 · The main small-signal parameters of a MOSFET are: Transconductance (g m). Output resistance (r o). Intrinsic gain (A V). Body-effect transconductance (g mb). The unity gain frequency (f T). Excepting f T, which we

Simple Small Signal Model for MOSFET l This is a simplified, 3-terminal small-signal model for a MOSFET l In later lectures we will develop a more complete model l g m = transconductance – defined as di ds/dv gs, units [Ohms]-1 l r o = output resistance – defined as [di ds/dv ds]-1, units Ohms University of California, Berkeley NMOS