ch01 Tamu ECEN 326

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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

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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.

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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

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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.

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