CMOS Wideband Noise Canceling LNAs and Receivers: A ...Condition for Noise Cancellation: Aaux = 1 β...

Thanks to Indrajit Das

CMOS Wideband Noise Canceling

LNAs and Receivers: A Tutorial

Nagarjuna Nallam

Department of Electronics and Electrical Engineering,

IIT Guwahati, Assam 781039, India

Outline

N. Nallam, “CMOS Wideband Noise Canceling LNAs and Receivers: A Tutorial”, 2016 APMC, New Delhi, India.

• Preliminaries

• Introduction to wideband noise canceling (NC) LNAs andreceivers

• Review of feedback and feedforward models for NC

• Macro models of MOSFETs and resistors

• Equivalent models of NC circuits and simulations

• Conclusions

Preliminaries: Noise in Electronics


No

isyR

No

isle

ssR

4KT∆f/R

No

isle

ss

MO

SF

ET

No

isy

MO

SF

ET

4KT γαgm∆f

Preliminaries: Noise factor


+

Amp

Pi Po

Ni No

SNRi =PiNi

; SNRo =PoNo

= Gain.PiGain.Ni+NA

;

Noise factor = SNRiSNRo

= PiNi.NoPo

= 1 + NAGain.Ni

> 1

If expressed in dB, Noise factor is referred as Noise figure and is

always > 0 dB.

Preliminaries: Noise factor of a cascaded system


+

Po

RsG2, F2G1, F1

Ps

P1

+

Fcas =PiPo.NoNs

= 1G1G2

.G1G2Ns+G2.NA1+NA2Ns

Fcas − 1 = NA1G1Ns +NA2

G1G2Ns

= (F1 − 1) + F2−1G1

Preliminaries: Noise figure of the receiver


IFprocessingPA LNA

PTx PRx

RF source RF source

Data

(NF)Rx is dominated by (NF)LNA

frequency

PowerSets up the Noise floor

Only the signals whose

amplitudes are greater

than the noise floor of

the Rx can be detected.

Preliminaries: LNA specifications


Chip

SAW

PCB

LNA

Mixer

Γ = 0

few mm

few µm

Maximize voltage

filter

1. Zin looking into the pin of the chip (i.e., including the pad and package parasitics) should be

50 Ω.

2. Output matching is not needed as the track length from the LNA output to the mixer input is

≪ λ.

3. Large gain, large IIP3 and small NF are needed.

Why wideband?


Modern radio receivers need to support multiple wireless

standards which span across the frequency spectrum!

Two ways of supporting:

Multiple Narrowband radios Wideband radio

f1 f2 fn f1 f2 fn

Outline


• Preliminaries





• Conclusions

Common Gate (CG) Wideband LNA


Vdd

ve

vin

Rs

RL

vout

vb

Rin =r0+RLgmr0+1

≈ 1gm

M0voutvin

= (gmr0+1)RLr0+Rs+RL+gmr0Rs

NFCG = 1 +γ

gmRs+

RsRL

(1 +1

gmRs)2 (1)

Resistive Shunt Feedback (RSF) Wideband LNA


Vdd

vg

Rf

vout

voutvin

≈ 1− gmRfRs

vin

Rin =1

gm1

vb M2

M1

NFRSF = 1 +4RsRf

+ γgm1Rs + γgm2Rs (2)

Wideband Noise Canceling LNAs†


Source (Rs)

Matching

Voltage-sensing

Amplifier Stage

Amplifier Stage

Combiner

(a)

Zinm

Zinv

v2inm

†F. Bruccoleri, E. Klumperink, and B. Nauta, Wide-band CMOS low-noise amplifier exploiting thermal noise canceling, IEEE J.

Solid-State Circuits, vol. 39, no. 2, pp. 275-282, Feb 2004.



−Aaux

v′out

Rf

(b)

Source (Rs)

Matching

Voltage-sensing

Amplifier Stage

Amplifier Stage

Combiner

(a)

Zinm

Zinv

Rs

v2inm





Vdd Vdd

−Av

vout

Vb

vout

Rf

(b) [2 - 3] (c) [4 - 6]

Source (Rs)

Matching

Voltage-sensing

Amplifier Stage

Amplifier Stage

(a) [2]

Combiner

Zinm

Zinv

Rs

Rs

v2inm



Wideband Noise Canceling Receiver†


vinRinRs

v2Rin

IRin

VRin

rmIRin

αVRin

v′out

Noise canceling Condition isrm = αRs

(a)

ve

outp

outn

†D. Murphy, H. Darabi, A. Abidi, A. Hafez, A. Mirzaei, M. Mikhemar, and M.-C. Chang, A blocker-tolerant, noise-cancelling

receiver suitable for wideband wireless applications, IEEE J. Solid-State Circuits, vol. 47, no. 12, pp. 2943-2963, Dec 2012.

Wideband Noise Canceling Receiver†


vinRinRs

v2Rin

IRin

VRin

rmIRin

αVRin

vin

RinRs

−gm

v′out v′out

Voltage Measurement Path(α = −gmRaux)

Current Measurement Path(rm = Rm)

Noise canceling Condition isrm = αRs

(a) (b)

Raux

Rmve

outp

outn ve

outp

outn

†D. Murphy, H. Darabi, A. Abidi, A. Hafez, A. Mirzaei, M. Mikhemar, and M.-C. Chang, A blocker-tolerant, noise-cancelling


Outline


• Preliminaries





• Conclusions

Feedforward Noise Canceling


Add a feed forward amplifier to nullify the noise of main amplifier at the

output [13].

Am Σ

Nm

Delay(τ1)

Σ

Attenuator(γ1) Σ

(τ2)Delay

Aaux

XZ

YA

Y

X1

Feedforward Noise Canceling


Add a feed forward amplifier to nullify the noise of main amplifier at the

output [13].

Am Σ

Nm

Delay(τ1)

Σ

Attenuator(γ1) Σ

(τ2)Delay

Aaux

XZ

YA

Y

X1

γ1 =1

Am, X1 = γ1Nm

YA = Aaux(γ1 Nm) Y = AmX +Nm

Z = Y − YA = AmX +Nm(1−Aauxγ1)

If, Aaux =1

γ1, Z = AmX

Noise Canceling Condition is Aaux = Am =1

γ1

Feedback Noise Reduction


AmX Y

Σ Σ

N1

β

e

e = X1+Amβ

AmX Y

Σ Σ

β

Y = AmX1+Amβ

Feedback Noise Reduction


AmX Y

Σ Σ

N1

β

e

e = X1+Amβ

(a) (b)

e = −βNm1+Amβ

AmX Y

Σ Σ

β

AmY

Σ Σ

Nm

β

Y = Nm1+Amβ

Y = AmX1+Amβ

Feedback-Feedforward Noise Canceling


e = X1+Amβ

− βNm1+Amβ

XAmΣ Σ

Nm

β

Aaux

ΣZ

YA

Y = AmX1+Amβ

+ Nm1+Amβ

e =X

1 +Amβ− βNm

1 +Amβ(3)

Y =AmX

1 +Amβ+

Nm1 +Amβ

(4)

Feedback-Feedforward Noise Canceling


e = X1+Amβ

− βNm1+Amβ

XAmΣ Σ

Nm

β

Aaux

ΣZ

YA

Aaux =1β

No Nm iff

Y = AmX1+Amβ

+ Nm1+Amβ

Condition for Noise Cancellation:

Aaux =1β

Overall Gain at NC condition:

ZX =

YX +

YAX =

Am1+Amβ

+1/β

1+Amβ=

1β or Aaux

Outline


• Preliminaries





• Conclusions

Macro Model of a MOSFET


vs

−gm

vs ioutiout

Σ

(a) (b)

Σ

in

vg

vgiout

iout

Macro Model of a MOSFET in CG configuration


vs

−gm

vs ioutiout

Σ

(a) (b)

Σ

in

vg

vgiout

iout

gm

vs ioutiout

Σiout

iniout

vs

(c)

Macro Model of a MOSFET in CS configuration


vs

−gm

vs ioutiout

Σ

(a) (b)

Σ

in

vg

vgiout

iout

−gm Σvg iout

in

gm

vs ioutiout

Σiout

invg

ioutiout

vs

(d) CS configuration(c) CG configuration

Macro Model of a Resistor


RfX Y

(a)

iyixvx vy

ix = iy

in



RfX Y

(a)

iyixvx vy

ix = iy

in

ix = iy (5)

ix = (vxRf

)− ( vyRf

) + in (6)



RfX Y

(a)

iyixvx vy

ix = iy

in

1Rf

Rf

(b)

in iy vy

Y

ixvx

X

ix = (vxRf

)− ( vyRf

) + in



RfX Y

(a)

iyixvx vy

ix = iy

in

1Rf

1Rf

RfRf

(c)†

in

iy vy

Y

ixvx

X

1Rf

Rf

(b)

in iy vy

Y

ixvx

X

ix = (vxRf

)− ( vyRf

) + in

in

†D. H. Mahrof, E. A. M. Klumperink, Z. Ru, M. S. Oude Alink and B. Nauta, Cancellation of opamp virtual ground imperfections

by a negative conductance applied to improve RF receiver linearity, IEEE J. Solid-State Circuits, vol. 49, no. 5, pp. 1112-1124,

May 2014.



RfX Y

(a)

1Rf

Rfiy

(d)

Σ

in

iyixvx vy

ix = iy

in

X

ix

Y

iy vy

1Rf

1Rf

RfRf

(c)†

in

iy vy

Y

ixvx

X

vx

1Rf

Rf

(b)

in iy vy

Y

ixvx

X

ix = (vxRf

)− ( vyRf

) + in

in

†D. H. Mahrof, E. A. M. Klumperink, Z. Ru, M. S. Oude Alink and B. Nauta, Cancellation of opamp virtual ground imperfections

by a negative conductance applied to improve RF receiver linearity, IEEE J. Solid-State Circuits, vol. 49, no. 5, pp. 1112-1124,

May 2014.

Outline


• Preliminaries





• Conclusions

Equivalent Model of a Common Gate LNA


Vdd

ve

gmve

ioutiout

Σ

(a) (b)

vin

Rs

RsvinRs

RL

RL

Σ

in

vout

vout

ie

Figure 1: (a) A CG amplifier, and (b) a feedback model of it.

ve =1

1+gmRsvin − Rs/RL1+gmRs vn

vout =gmRL

1+gmRsvin +

11+gmRs

vn, where vn = in RL

Equivalent Model of a NC Common Gate LNA


gmve

ioutiout

Σ

RsvinRs

RL

Σ

inv′out

Aaux

ie

Σ

vout

Noise canceling condition: Aaux =RLRs

Simulation of CG NC-LNA


Vdd = 1.8 V

ve

vin

outp outn

−Aaux50 Ω

350 Ω

80µ0.18µ

v′out

2.5 mA

β = RsRL

= 17

VCVS

β = RsRL

= 17

Aaux =1β

= 7

Simulation of CG NC-LNA


4 5 6 7 8 9 100

0.5

1

1.5

2

2.5

3

3.5

Auxiliary Amplifier Gain (Aaux)

50 MHz100 MHz

500 MHz1 GHz

No

ise

atv′ out

inn

V/s

qrt

(Hz)

Aaux =1β= 7

1

2

3

4

5

6

7

8

Frequency (Hz)

v′out = outp − outnoutp

10M 100M 1G 10G

Vo

lta

ge

Ga

in

|v′outvin

| = | 1β| = 7

(a)

(b)

Equivalent Model of the NC RSF LNA


−gm Σ

in

Σ

Rf

Rs

ve

vinRs

v′out

ioutiout

−1− RfRs

Σ

1Rf

Rf

1Rf

vout

ve =1

1+gmRsvin +

Rs/Rf1+gmRs

vn

vout =1−gmRf1+gmRs

vin +1+Rs/Rf1+gmRs

vn

Simulation of RSF NC-LNA


Vdd = 1.8 V

50 Ω 250 Ω

vin

−Aaux

Σv′out

vout70 µ0.18 µ

160 µ0.18 µ

β = RsRf

= 15

ve

1.38 mA

VCVS

NC condition: Aaux = 1 +1β = 6

Gain of amplifier at NC = 1/β = 5

Equivalent Model of a Wideband Receiver


Rs

vin

(b)

ve

Rin Rm

veoutn

rmioutiout

outn

iout

1Rin

Σ

in

Rin

(a)rm =

Rmπ

Rs

vindue to themixer gain

ve =1

1+ RsRin

vin − −Rs/rm1+ RsRin

vn

outn =−rm/Rin1+ Rs

Rin

vin +1

1+ RsRin

vn, where vn = − inrm

Simulation of the Wideband NC Receiver


vin

50 Ω50 Ω

−gm

v′out

250 Ω

250 Ω

outn

outpV CCS

V CV S

V CV S

gm = 20mS

Iaux

Im

Simulation of a Wideband NC Receiver


0

0.20.4

0.60.8

11.2

1.41.6

1.82

Relative input frequency (Hz)

v′out/vinoutn/vin

1 10 100 1K 10K 100K 1M 10M 100M200M

Vo

lta

ge

ga

in

|v′outvin

| = | 1β| = | 5

π| = 1.59

0 0.5 1 1.5 2 2.5 3 3.5 4 4.50

0.05

0.1

0.15

0.2

0.25

Auxiliary path gain (Aaux)

Ou

tpu

tn

ois

evo

lta

ge

inn

V/√

Hz

β = πRsRm

= π5

Aaux =1β= 5

π≈ 1.59

PNOISE analysis

(a)

(b)

|outpvin

| = | Am1+Amβ

| = |2.5π| = 0.79

Outline


• Preliminaries





• Conclusions

Conclusions


• Shown that the NC is a feedback-feedforward technique

• In a NC amplifier/receiver, if the feedback factor of the mainamplifier/receiver is β, then the gain of the auxiliary amplifier/receiver(Aaux) needed to cancel the noise of the main amplifier/receiver isequal to |1/β|

• Under this noise canceling condition, the overall gain of theNC-wideband amplifier/receiver is equal to |1/β|

Indrajit Das, Nagarjuna Nallam, “The Role of Feedback in Noise Canceling LNAsand Receivers“, to appear in IEEE Micro. Mag.

References


[ 1 ] B. Razavi, RF Microelectronics. Upper Saddle River, New Jersey: Prentice Hall Press, 2011, ch. 5.

[ 2 ] F. Bruccoleri, E. Klumperink, and B. Nauta, Wide-band CMOS low-noise amplifier exploiting thermal noise canceling,

IEEE J. Solid-State Circuits, vol. 39, no. 2, pp. 275-282, Feb 2004.

[ 3 ] Y.H. Yu, Y.S. Yang, and Y.J. Chen, A compact wideband CMOS low noise amplifier with gain flatness enhancement, IEEE

J. Solid-State Circuits, vol. 45, no. 3, pp. 502-509, March 2010.

[ 4 ] C.F. Liao and S.I. Liu, A broadband noise-canceling CMOS LNA for 3.1-10.6-GHz UWB receivers, IEEE J. Solid-State

Circuits, vol. 42, no. 2, pp. 329-339, Feb 2007.

[ 5 ] W.H. Chen, G. Liu, B. Zdravko, and A. Niknejad, A highly linear broadband CMOS LNA employing noise and distortion

cancellation, IEEE J. Solid-State Circuits, vol. 43, no. 5, pp. 1164-1176, May 2008.

[ 6 ] S. Blaakmeer, E. Klumperink, D. Leenaerts, and B. Nauta, Wideband Balun-LNA with simultaneous output balancing,

noise-canceling and distortion-canceling, IEEE J. Solid-State Circuits, vol. 43, no. 6, pp. 1341-1350, June 2008.

[ 7 ] D. Murphy, H. Darabi, A. Abidi, A. Hafez, A. Mirzaei, M. Mikhemar, and M.-C. Chang, A blocker-tolerant, noise-cancelling


[ 8 ] D. Murphy, H. Darabi, and H. Xu, A noise-cancelling receiver resilient to large harmonic blockers, IEEE J. Solid-State

Circuits, vol. 50, no. 6, pp. 1336-1350, June 2015.

[ 9 ] C. McNeilage, E. Ivanov, P. Stockwell, and J. Searls, Review of feedback and feedforward noise reduction techniques, in

Frequency Control Symposium, 1998. Proceedings of the 1998 IEEE International, May 1998, pp. 146-155.

[ 10 ] D. Mahrof, E. Klumperink, Z. Ru, M. Oude Alink, and B. Nauta, Cancellation of opamp virtual ground imperfections by a

negative conductance applied to improve RF receiver linearity, IEEE J. Solid-State Circuits, vol. 49, no. 5, pp. 1112-1124, May

2014.

Notes


OutlineOutlinePreliminaries: Noise factorPreliminaries: Noise in ElectronicsPreliminaries: Noise factor of a cascaded systemPreliminaries: Noise figure of the receiverPreliminaries: LNA specificationsWhy wideband?OutlineCommon Gate (CG) Wideband LNAResistive Shunt Feedback (RSF) Wideband LNAWideband Noise Canceling LNAsWideband Noise Canceling LNAsWideband Noise Canceling LNAsWideband Noise Canceling LNAsWideband Noise Canceling LNAsWideband Noise Canceling ReceiverWideband Noise Canceling ReceiverOutlineFeedforward Noise CancelingFeedforward Noise CancelingFeedback Noise ReductionFeedback Noise ReductionFeedback-Feedforward Noise CancelingFeedback-Feedforward Noise CancelingOutlineMacro Model of a MOSFETMacro Model of a MOSFET in CG configurationMacro Model of a MOSFET in CS configurationMacro Model of a ResistorMacro Model of a ResistorMacro Model of a ResistorMacro Model of a ResistorMacro Model of a ResistorOutlineEquivalent Model of a Common Gate LNA Equivalent Model of a NC Common Gate LNASimulation of CG NC-LNASimulation of CG NC-LNAEquivalent Model of the NC RSF LNASimulation of RSF NC-LNASimulation of RSF NC-LNAEquivalent Model of a Wideband ReceiverSimulation of the Wideband NC ReceiverSimulation of a Wideband NC ReceiverOutlineConclusionsReferencesNotes

CMOS Wideband Noise Canceling LNAs and Receivers: A ...Condition for Noise Cancellation: Aaux = 1 β...

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