SLIDE 1
NFET symbol and cross section
- Lecture 1: Basic Analog CMOS
2
INF5470 Fall 2011 Lecture 1: Basic Analog CMOS NFET symbol and - - PowerPoint PPT Presentation
INF5470 Fall 2011 Lecture 1: Basic Analog CMOS NFET symbol and - - PowerPoint PPT Presentation
INF5470 Fall 2011 Lecture 1: Basic Analog CMOS NFET symbol and cross section Lecture 1: Basic Analog CMOS
SLIDE 2
SLIDE 3
NFET formulae
IDS = IF − IR IF(R) = ISln2
- 1 + e
VG−VT0−nVS(D) 2nUT
- In saturation:
IF >> IR Triode region/linear region: IF ≈ IR
Lecture 1: Basic Analog CMOS 3
SLIDE 4
NFET characteristics ID vs. VDS
1 2 3 4 5 0.5 1 1.5 2 2.5 3 3.5 4x 10
−5
VDS ID
Lecture 1: Basic Analog CMOS 4
SLIDE 5
NFET Formulae Simplified in Weak Inversion
Weak inversion/subthreshold: (IF << IS) = (VG < VT0 + nVS) NFET equation simplifies to: IF = ISe
VG−VT0−nVS nUT Lecture 1: Basic Analog CMOS 5
SLIDE 6
NFET Formulae Simplified in Strong Inversion
Strong inversion/above threshold: (IF >> IS) = (VG > VT0 + nVS) simplifies to: IF(R) = IS 4 VG − VT0 − nVS(D) nUT 2
Lecture 1: Basic Analog CMOS 6
SLIDE 7
NFET Early effect
IF =
VD+VEarly VEarly
IF
Lecture 1: Basic Analog CMOS 7
SLIDE 8
NFET characteristics ID vs VGS
1 2 3 4 5 1 2 3 4 5 6x 10
−4
VGS ID 1 2 3 4 5 10
−30
10
−20
10
−10
10 VGS log ID Lecture 1: Basic Analog CMOS 8
SLIDE 9
Briefly Mentioned: Gate Leakeage/Direct Tunneling
tox ≤ 2 − 3nm Jg = A V 2
- x
t2
- x e
−
B 1−
- 1− Voxqe
φox 2 3 Vox tox
if Vox < φox
qe
A V 2
- x
t2
- x e
−
B Vox tox
if Vox > φox
qe
(1)
Lecture 1: Basic Analog CMOS 9
SLIDE 10
Capacitor Symbol and Cross Section
Lecture 1: Basic Analog CMOS 10
SLIDE 11
Capacitor formulae
V = 1
C Q δV δt = 1 C I
Lecture 1: Basic Analog CMOS 11
SLIDE 12
Resistor Layout
- Lecture 1: Basic Analog CMOS
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SLIDE 13
Resistor Formula
V = RI
Lecture 1: Basic Analog CMOS 13
SLIDE 14
Current Mirror Schematics
- Lecture 1: Basic Analog CMOS
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SLIDE 15
Current Mirror formulae
Iout = Iin (if both transistors are in saturation, and have the same W/L ratio, and neglecting the Early effect)
Lecture 1: Basic Analog CMOS 15
SLIDE 16
Differential Pair Schematics
- Lecture 1: Basic Analog CMOS
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SLIDE 17
Differential Pair Formulae
Ib = I1 + I2 = ISe
−VT0−VC nUT
- e
V1 nUT + e V2 nUT
- I1
I2 = I1 Ib−I1 = e
V1−V2 nUT Lecture 1: Basic Analog CMOS 17
SLIDE 18
Transconductance Amplifier Schematics
- Lecture 1: Basic Analog CMOS
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SLIDE 19
Transconductance Amplifier Formulae
Iout = Ib
e
V+ nUT −e V− nUT
e
V+ nUT +e V− nUT
= Ib tanh V+−V−
2nUT
Lecture 1: Basic Analog CMOS 19
SLIDE 20
Resistive Net
Lecture 1: Basic Analog CMOS 20
SLIDE 21
Resistive Net Formulae
V RV = δ2 δx2δy2 V RH
Lecture 1: Basic Analog CMOS 21
SLIDE 22
Diffuser Net
- Lecture 1: Basic Analog CMOS
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SLIDE 23
Diffuser Net Formulae
V ∗ R∗
V =
δ2 δx2δy2 V ∗ R∗
H
V ∗ = −e
−V UT
1 R∗ = g∗ = ISe
VG−VT0 nUT
Attention: transistors must be in subthreshold for this to be applicable!
Lecture 1: Basic Analog CMOS 23
SLIDE 24
Winner Take All (WTA) Principle
- +
+ + + + + + + + + + +
Lecture 1: Basic Analog CMOS 24
SLIDE 25
WTA Basic Circuit
- Lecture 1: Basic Analog CMOS
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SLIDE 26
Smooth Cooperative/Cross Exitation WTA
- Lecture 1: Basic Analog CMOS
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SLIDE 27
Hysteretic WTA
- Lecture 1: Basic Analog CMOS
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SLIDE 28
Local/Cross Inhibition WTA
- Lecture 1: Basic Analog CMOS
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SLIDE 29
Weekly Task
Propose a circuit that computes: Iout = 2 Iin Yout = C1 log C2Xin (Xin and Yout may both be either I or V)
Lecture 1: Basic Analog CMOS 29