ch01 tamu ecen 326
DESCRIPTION
Lecture from TAMU ECEN 326TRANSCRIPT
1
ECEN-326 Electronic Circuits
CH1 Why Microelectronics?
CH2-CH8 Covered in ECEN325
CH10 Differential Amplifiers
CH9 Cascode Stages and Current Mirrors
CH16 CMOS Amplifiers
CH11 Frequency Response
CH12 Feedback & Stability
CH13 Output Stages
2
1.1 Electronics versus Microelectronics
1.2 Example of Electronic System: Cellular Telephone
1.3 Analog versus Digital
Chapter 1 Why Microelectronics?
ECEN-325 Spring 2013 S. Hoyos (From Razavi's textbook) 3
Cellular Technology
An important example of microelectronics.
Microelectronics exist in black boxes that process the
received and transmitted voice signals.
ECEN-325 Spring 2013 S. Hoyos (From Razavi's textbook) 4
Frequency Up-conversion
Voice is “up-converted” by multiplying two sinusoids.
When multiplying two sinusoids in time domain, their
spectra are convolved in frequency domain.
5
Digital Signal Processing
• Noise immunity, robustness.
• Unlimited precision or accuracy.
• Flexibility, programmability, and scalability.
• Electronic design automation (EDA) tools widely
available and successful.
• Benefiting from Moore’s law – “The number of transistors
on a chip doubles every 18 months,” IEDM, 1975.
– Cost/function drops 29% every year.
– That’s 30X in 10 years.
ECEN-325 Spring 2013 S. Hoyos (From Razavi's textbook) 5
Analog Signal Processing
• Sensitive to noise – SNR (signal-to-noise ratio).
• Subject to device nonlinearities – THD (total harmonic distortion).
• Sensitive to device mismatch and process variations.
• Difficult to design, simulate, layout, test, and debug.
• Inevitable, often limits the overall system performance.
• Scaling scenario:
– Enjoyed scaling until ~0.35-µm technology node.
– High-speed, low-resolution ADCs keep benefiting.
– High SNR design difficult to scale with low supplies (≤ 3.3V).
ECEN-325 Spring 2013 S. Hoyos (From Razavi's textbook) 6
Communication Receiver
1
2
3
LNA
RF Filter
RF
Anti-
Aliasing
Filter
A/D
SCF, Gm
C
OP-RC
Anti-
Aliasing
Filter
A/D
Dig. Filter
DSP
DSPRF
RF Filter
RF Filter
A/D
Dig. Filter
DSPG
Dig. Mod.RF
IF or BB
DR
DR
BB
ECEN-325 Spring 2013 S. Hoyos (From Razavi's textbook) 7
Mixed-Signal Hearing Aid
Ref: D. G. Gata, “A 1.1-V 270-μA
mixed-signal hearing aid chip,”
JSSC, pp. 1670-8, Dec. 2002.
ΣΔ
A/DDSP
AGC Decimation
Filter
ΣΔ
D/A
H-Bridge
Driver
ECEN-325 Spring 2013 S. Hoyos (From Razavi's textbook) 8
ECEN-325 Spring 2013 S. Hoyos (From Razavi's textbook) 9
Transmitter
Two frequencies are multiplied and radiated by an antenna
in (a).
A power amplifier is added in (b) to boost the signal.
ECEN-325 Spring 2013 S. Hoyos (From Razavi's textbook) 10
Receiver
High frequency is translated to DC by multiplying by fC.
A low-noise amplifier is needed for signal boosting without excessive noise.
ECEN-325 Spring 2013 S. Hoyos (From Razavi's textbook) 11
Digital or Analog?
X1(t) is operating at 100Mb/s and X2(t) is operating at 1Gb/s.
A digital signal operating at very high frequency is very
“analog”.
Why CMOS?
Desired features:
Low cost
Low power
High integration
Single chip radio
TI Bluetooth SoC 2005 ~
7 mm²
Just 20% of SoC is
RF/analog. Rest is digital
logic and memory.
ECEN-325 Spring 2013 S. Hoyos (From Razavi's textbook) 12