Low Noise Amplifier(LNA)

⇒Always working

⇒LNA power reduction is must for low power transceiver

Daiki Oki, Satoru Kawauchi, Li CongBing, Masataka Kamiyama,

A Power-Efficient Noise Canceling Technique

Using Signal-Suppression Feed-forward for Wideband LNAs

Department of Electronic Engineering, Gunma University, 1-5-1 Tenjin-cho, Kiryu 365-8515, Japan † Sanyo Semiconductor Co., Ltd.

Seiichi Banba †, Toru Dan †, Nobuo Takahashi †, Koji Sakata †, Haruo Kobayashi, Nobukazu Takai

Basic Noise Cancelling Technique

Power increase by Av.c operation

Division of 𝑹𝒇

Suppress input signal of Av.c (vA)

Power reduction of Av.c

Proposed Solution (Signal Suppression Technique) Research Goal

Noise Cancelling Technique

Signal Suppression

low noise and low power LNA. Realize

Proposed Noise Cancelling Technique Noise, Distortion Analysis of Proposed LNA

Performance Tradeoff

52

53

54

55

56

57

58

0 10 20 30 40 50 60

Rf2=0Ω

Rf2=10Ω

Rf2=20Ω

Rf2=30Ω

Rf2=40Ω

Rf2=50Ω

Signal Suppression at Noise Cancelling Amp

Power reduction of Av.c

Noise cancellation Av.c =𝑹𝑺 + 𝑹𝒇𝟏 + 𝑹𝒇𝟐 𝑹𝑺 + 𝑹𝒇𝟐 𝜸𝒈𝑴𝒊 + 𝑹𝒇𝟐

𝑹𝑺 + 𝑹𝒇𝟐𝟐

𝜸𝒈𝑴𝒊 + 𝑹𝒇𝟐

Distortion cancellation Av.c =𝑹𝑺 + 𝑹𝒇𝟏 + 𝑹𝒇𝟐

𝑹𝑺 + 𝑹𝒇𝟐= 𝟏 +

𝑹𝒇𝟏

𝑹𝑺 + 𝑹𝒇𝟐

Av.c = Noise cancelation point 𝑹𝒇𝟏 + 𝑹𝒇𝟐 = 𝒄𝒐𝒏𝒔𝒕

Optimal Av.c

𝐴𝑣,𝑐 =𝑔𝑀2

𝑔𝑀3

Proposed Circuit for Simulation Performance Tradeoff

Simulation when Rf2=20Ω

・This work provides optimal tradeoff in between NF and power

in wide-band LNA.

⇒By adjusting feedback resistor Rf2.

・SPECTRE simulation with 90nm CMOS has proved

noise cancelling.

low power.

distortion cancellation.

good frequency characteristics with Rf2=20Ω

LNA frequency characteristics

Little influence by 𝑨𝒗,𝒄

Intro

du

ctio

n

Pro

po

sed

Circ

uit

Sim

ula

tion

Summary

Av,c=4.83 (noise cancelling point)

NF: 3.25dB Power : 8.23mW IIP3 : -2dBm

⇒Low power and low noise.

Av,c=6 (distortion cancelling point)

NF : 3.36dB Power : 9.87mW IIP3 : -1.53dBm

⇒Only small improvement of IIP3,

high power.

time(𝐧𝐬)

TSMC 90nm CMOS parameters

0

1

2

3

4

5

6

0

2

4

6

8

10

12

14

16

0 10 20 30 40 50

NF

[dB

]

Pow

er[m

W]

Rf2[Ω]

Av.c vs power, NF

PowerNF

-8

-7

-6

-5

-4

-3

-2

-1

0

1 2 3 4 5 6 7 8 9 10

IIP

3[d

Bm

]

Av.c

Av.c vs IIP3

0

1

2

3

4

5

6

7

8

9

10

1 2 3 4 5 6 7 8 9 10

NF

[dB

]

Av.c

Av.c vs NF

Rf2 = 10Ω

Distortion cancellation point

Input frequency : 849, 851 MHz

Fundamental frequency : 849 MHz IM3 : 847 MHz Small 𝑹𝒇𝟐

・・・low NF, high power

Large 𝑹𝒇𝟐

・・・low power, high NF

8

8.5

9

9.5

10

4.83 5.415 6

Pow

er [

mW

]

Av.c

Power

3

3.2

3.4

3.6

3.8

4

4.83 5.415 6

NF

[dB

]

Av.c

NF(1GHz)

-2.5

-2

-1.5

-1

-0.5

0

4.83 5.415 6

IIP

3[d

Bm

]

Av.c

IIP3

Performance change by 𝐀v.c

[1] F. Bruccoleri, E. A. M. Klumperink, B. Nauta

“ A Power-Efficient Noise Suppression Technique Using Signal-Nulled

Feedback for Low-Noise Wideband Amplifiers”

IEEE Trans on Circuits and Systems (Jan. 2012).

“A Noise-Suppressed Amplifier with a Signal-Nulled Feedback for Wideband

Applications”

IEEE Asian Solid-State Circuits Conference,(Nov.2008).

References

𝑣𝑛,𝑜𝑢𝑡2

= 4𝑘𝑇𝐵 𝑅𝑆 + 𝑅𝑓1 + 𝑅𝑓2 − 𝐴𝑣,𝑐 𝑅𝑆 + 𝑅𝑓22

𝛾𝑔𝑀𝑖 + 𝑅𝑓1 + 1 − 𝐴𝑣,𝑐2

𝑅𝑓2

“Wide-Band CMOS Low-Noise Amplifier Exploiting Thermal Noise Cancelling”

IEEE Journal of Solid-State Circuits,(Feb. 2004).

[2] C.-F. Li, S.-C. Chou, G.-H. Ke, P.-C. Huang

[3] C.-F. Li, S.-C. Chou, P.-C. Huang

①

②

③

in,Mi in,Mi

Channel noise

① ③

②

in,Mi : channel noise

in,Rf1 : Rf1 noise

in,Rf2 : Rf𝟐 noise

50Ω 0

Hig

h

Lo

w

Suppression level

Rf2

Rf2

0

50Ω

580

vA(𝐦𝐕)

570

560

550

540

530

520

P71