Lect_12 - ECE442 SolidStateDevices&Circuits 12.ICTechniques...

Info iconThis preview shows pages 1–17. Sign up to view the full content.

View Full Document Right Arrow Icon
1 Jose E. Schutt Aine ECE 442 ECE 442 Solid State Devices & Circuits 12. IC Techniques Jose E. Schutt-Aine Electrical & Computer Engineering University of Illinois [email protected]
Background image of page 1

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

View Full DocumentRight Arrow Icon
2 Jose E. Schutt Aine ECE 442 Background IC Requirements – Biasing of ICs is based on the use of constant current sources – Use current mirrors – Source circuits are used as loads
Background image of page 2
3 Jose E. Schutt Aine ECE 442 Analog Design Requirements – Analog ICs may need resistors and capacitors for the design of amplifiers – Resistors and capacitors occupy the space of tens or hundreds of MOS devices – It is important to minimize their use Integrated Circuits
Background image of page 3

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

View Full DocumentRight Arrow Icon
4 Jose E. Schutt Aine ECE 442 Amplifier with Diode-Connected Load Amplifier is single stage M1 driving a load impedance which is that looking into the source of M2
Background image of page 4
5 Jose E. Schutt Aine ECE 442 Output Impedance 2 22 2 2 2 2 s sm s m b s ds v ig vg v r =+ + To calculate output impedance, connect voltage supply at source of M2 and measure current
Background image of page 5

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

View Full DocumentRight Arrow Icon
6 Jose E. Schutt Aine ECE 442 Output Impedance 2 2 222 2 1 s s sm m b d s v R ig g g == ++ 12 22 2 1 out ds S mm bd s Rr R gg g & M1 sees this load in parallel with its own output impedance, r ds1
Background image of page 6
7 Jose E. Schutt Aine ECE 442 Incremental model The source to-body voltage changes in M2 Î use transconductance term g mb2 1 1 22 2 1 m MB m out mm bd sd s g Ag R gg g g =− ++ +
Background image of page 7

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

View Full DocumentRight Arrow Icon
8 Jose E. Schutt Aine ECE 442 Gain – Diode-Connected Amp 1 2 m MB m g A g ≈− 2( / ) mn o x D gC W L I μ = 1/2 11 22 / ) (/ ) ) / ) no x D MB x D CW L I WL A CWL I =− The magnitude of the voltage gain varies as the square root of the aspect ratio
Background image of page 8
9 Jose E. Schutt Aine ECE 442 High-Frequency – Diode-Connected Amp The amplifying stage has two upper corner frequencies; one caused by the input circuit and one caused by the output circuit. 1 2 in high g in f R C π = () 1 2 out high out out L f R CC = + and
Background image of page 9

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

View Full DocumentRight Arrow Icon
10 Jose E. Schutt Aine ECE 442 High-frequeny: Simplified Model f in-high and f out-high may be widely or narrowly separated
Background image of page 10
11 Jose E. Schutt Aine ECE 442 pMOS Diode-Connected Amp Analog Design Requirements – Load device can be replaced by pMOS transistor – Eliminates body effect of the load device – Increases the resistance () 1/2 11 22 /3 / // no x n MB po x p CW L W L A L W L μ ⎡⎤ =≈ ⎢⎥ ⎣⎦
Background image of page 11

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

View Full DocumentRight Arrow Icon
12 Jose E. Schutt Aine ECE 442 pMOS Diode-Connected Amp 1122 out db g dd b gs CCC C C = +++ 221 2 11 out md sd s m R gg g g =≈ ++ To approximate upper corner frequency, calculate The output impedance
Background image of page 12
13 Jose E. Schutt Aine ECE 442 Transistor Biasing
Background image of page 13

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

View Full DocumentRight Arrow Icon
14 Jose E. Schutt Aine ECE 442 Transistor Biasing
Background image of page 14
15 Jose E. Schutt Aine ECE 442 Current Mirrors A current mirror will reproduce a reference current to the output while allowing the the output voltage to assume any value within a specified range. I o =KI in where K is a factor that can be less than or equal or greater than 1
Background image of page 15

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

View Full DocumentRight Arrow Icon
16 Jose E. Schutt Aine ECE 442 MOS Current Mirror () 2 ' 1 1 1 2 Dn G S T n W Ik V V L ⎛⎞ =−
Background image of page 16
Image of page 17
This is the end of the preview. Sign up to access the rest of the document.

This note was uploaded on 09/07/2011 for the course ECE 442 taught by Professor Schutt-aine during the Summer '08 term at University of Illinois at Urbana–Champaign.

Page1 / 62

Lect_12 - ECE442 SolidStateDevices&Circuits 12.ICTechniques...

This preview shows document pages 1 - 17. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online