P Channel MOSFET-Introduction to Microelectronic Circuits-Lecture 24 Slides-Electrical Engineering, Slides of Microelectronic Circuits

Download P Channel MOSFET-Introduction to Microelectronic Circuits-Lecture 24 Slides-Electrical Engineering and more Slides Microelectronic Circuits in PDF only on Docsity! 1 Lecture 24, Slide 1EECS40, Fall 2003 Prof. King Lecture #24 OUTLINE • The common-source (CS) amplifier – load line analysis – DC bias circuit example – small-signal analysis of CS amplifier Reference Reading • Howe & Sodini: Chapter 8.1, 8.3 • Hambley (posted online): Chapter 12.2-12.5 Lecture 24, Slide 2EECS40, Fall 2003 Prof. King Notation • Subscript convention (Lecture 2, Slide 11): VDS ≡ VD – VS , VGS ≡ VG – VS , etc. • Double-subscripts denote DC sources (Lecture 23, Slide 7): VDD , VCC , ISS , etc. • To distinguish between DC and AC components of an electrical quantity, the following convention is used: – DC quantity: upper-case letter with upper-case subscript ID , VDS , etc. – AC quantity: lower-case letter with lower-case subscript id , vds , etc. – Total (DC + AC) quantity: lower-case letter with upper-case subscript iD , vDS , etc. 2 Lecture 24, Slide 3EECS40, Fall 2003 Prof. King P-Channel MOSFET Example • In a digital circuit, a p-channel MOSFET in the ON state is typically used to charge a capacitor connected to its drain terminal: – gate voltage VG = 0 V – source voltage VS = VDD (power-supply voltage) – drain voltage VD initially at 0 V, charging toward VDD Cload       −≅ DDp DSATp DD eq VI VR λ 6 51 4 3 VDD 0 V iD ( )2 2 TpDD p DSAT VVL WkI − ′ −= Lecture 24, Slide 4EECS40, Fall 2003 Prof. King Common-Source (CS) Amplifier • The input voltage vs causes vGS to vary with time, which in turn causes iD to vary. VDD RD + vOUT = vDS − + vIN = vGS − + –VBIAS vs − + iD • The changing voltage drop across RD causes an amplified (and inverted) version of the input signal to appear at the drain terminal.