lecture23annotat

# lecture23annotat - 6.012 Microelectronic Devices and...

This preview shows pages 1–6. Sign up to view the full content.

6.012 - Microelectronic Devices and Circuits - Fall 2005 Lecture 23-1 Lecture 23 - Frequency Response of Ampliﬁers (I) Common-Source Amplifier December 1, 2005 Contents : 1. Introduction 2. Intrinsic frequency response of MOSFET 3. Frequency response of common-source ampliﬁer 4. Miller eﬀect Reading assignment: Howe and Sodini, Ch. 10, §§ 10.1-10.4

This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document
6.012 - Microelectronic Devices and Circuits - Fall 2005 Lecture 23-2 Key questions How does one assess the intrinsic frequency response of a transistor? What limits the frequency response of an ampliﬁer? What is the ”Miller eﬀect”?
6.012 - Microelectronic Devices and Circuits - Fall 2005 Lecture 23-3 1. Introduction Frequency domain is a major consideration in most ana - log circuits. Data rates, bandwidths, carrier frequencies all pushing up. Motivation: Processor speeds Traﬃc volume ↑⇒ data rates More bandwidth available at higher frequencies in the spectrum MMDS 3G Skybridge LMDS Spacewav WE Datacom Frequency 0 0 4 20 25 40 50 60 2 8 45 100 155 500 Video WirelessMAN Teledesic 'V Band' DOM Radio BW (MHz) Figure by MIT OCW.

This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document
6.012 - Microelectronic Devices and Circuits - Fall 2005 Lecture 23-4 2. Intrinsic frequency response of MOSFET 2 How does one assess the intrinsic frequency response of a transistor? f t short-circuit current- gain cut-oﬀ frequency -g [GHz] Consider MOSFET biased in saturation regime with small- signal source applied to gate: V DD i D =I D +i out i G =i in v s V GG v s at input i out : transistor eﬀect i in due to gate capacitance | i i in |↓ out Frequency dependence: f ↑⇒ i in ↑⇒ i out f t frequency at which | | =1 i in
6.012 - Microelectronic Devices and Circuits - Fall 2005 Lecture 23-5 Complete small-signal model in saturation: G S D + - v gs C gs C gd C db C sb g m v gs g mb v bs r o + v bs - i out v s + - i in B v bs =0 + + - - v gs g m v gs i out i in v s C gs C gd 1 2 node 1 : i in v gs jωC v gd =0 i in = v ( C + C ) node 2 : i out g m v + v

This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document
This is the end of the preview. Sign up to access the rest of the document.

{[ snackBarMessage ]}

### Page1 / 18

lecture23annotat - 6.012 Microelectronic Devices and...

This preview shows document pages 1 - 6. Sign up to view the full document.

View Full Document
Ask a homework question - tutors are online