CMOS Wideband Noise Canceling LNAs and Receivers: A Tutorial

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1 CMOS Wideband Noise Canceling LNAs and Receivers: A Tutorial Nagarjuna Nallam Department of Electronics and Electrical Engineering, IIT Guwahati, Assam , India Thanks to Indrajit Das

2 Outline Preliminaries Introduction to wideband noise canceling (NC) LNAs and receivers Review of feedback and feedforward models for NC Macro models of MOSFETs and resistors Equivalent models of NC circuits and simulations Conclusions

3 Outline Preliminaries Introduction to wideband noise canceling (NC) LNAs and receivers Review of feedback and feedforward models for NC Macro models of MOSFETs and resistors Equivalent models of NC circuits and simulations Conclusions

4 Preliminaries: Noise in Electronics Noisy R Noisless R 4KT f/r Noisy MOSFET Noisless MOSFET 4KT γ α g m f

5 Preliminaries: Noise factor P i P o Amp + N i N o SNR i = P i N i ; SNR o = P o N o = Gain.P i Gain.N i +N A ; Noise factor = SNR i SNR o = P i N i. N o P o = 1+ N A Gain.N i > 1 If expressed in db, Noise factor is referred as Noise figure and is always > 0 db.

6 Preliminaries: Noise factor of a cascaded system P 1 P o R s G 2,F 2 G 1,F 1 P s + + F cas = P i P o. N o N s = 1 G 1 G 2. G 1G 2 N s +G 2.N A1 +N A2 N s F cas 1 = N A1 G 1 N s + N A2 G 1 G 2 N s = (F 1 1)+ F 2 1 G 1

7 Preliminaries: Noise figure of the receiver P Tx P Rx Data PA LNA IF processing RF source RF source Only the signals whose amplitudes are greater than the noise floor of the Rx can be detected. Power (NF) Rx is dominated by (NF) LNA Sets up the Noise floor frequency

8 Preliminaries: LNA specifications PCB few mm Maximize voltage Mixer SAW filter LNA Γ = 0 few µm Chip 1. Z in 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.

9 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 f 1 f 2 f n f 1 f 2 f n

10 Outline Preliminaries Introduction to wideband noise canceling (NC) LNAs and receivers Review of feedback and feedforward models for NC Macro models of MOSFETs and resistors Equivalent models of NC circuits and simulations Conclusions

11 Common Gate (CG) Wideband LNA Vdd R L v out v b M 0 v out v in = (g m r 0 +1)R L r 0 +R s +R L +g m r 0 R s R s v e v in R in = r 0+R L g m r g m NF CG = 1+ γ g m R s + R s R L (1+ 1 g m R s ) 2 (1)

12 Resistive Shunt Feedback (RSF) Wideband LNA Vdd v b M 2 v out R s v g M 1 v out v in 1 g m v in R in = 1 g m1 NF RSF = 1+ 4R s +γg m1 R s +γg m2 R s (2)

13 Wideband Noise Canceling LNAs Source (R s ) Z inv Z inm v 2 inm Matching Amplifier Stage Voltage-sensing Amplifier Stage (a) Combiner 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 , Feb 2004.

14 Wideband Noise Canceling LNAs Source (R s ) Z inv Z inm v 2 inm Matching Amplifier Stage Voltage-sensing Amplifier Stage (a) Combiner v out R s A aux (b) 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 , Feb 2004.

15 Wideband Noise Canceling LNAs Source (R s ) Z inv Z inm v 2 inm Matching Amplifier Stage Voltage-sensing Amplifier Stage (a) Combiner v out R s A aux (b) 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 , Feb 2004.

16 Wideband Noise Canceling LNAs Source (R s ) Z inv Z inm v 2 inm Matching Amplifier Stage Voltage-sensing Amplifier Stage (a) Combiner v out R s A aux (b) 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 , Feb 2004.

17 Wideband Noise Canceling LNAs Source (R s ) Z inm v 2 inm Matching Amplifier Stage Combiner Z inv Voltage-sensing Amplifier Stage (a) [2] Vdd Vdd v out v out V b R s A v R s (b) [2-3] (c) [4-6] 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 , Feb 2004.

18 Wideband Noise Canceling Receiver Noise canceling Condition is r m = αr s out p V Rin αv Rin v out v e v 2 R in v in R s R in I Rin r m I Rin out n (a) 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 , Dec 2012.

19 Wideband Noise Canceling Receiver Noise canceling Condition is r m = αr s Voltage Measurement Path (α = g m R aux ) out p g m R aux out p V Rin αv Rin v out v out v e v 2 R in R s R in R m v in R s R in I Rin r m I Rin out n v in v e out n (a) Current Measurement Path (r m = R m ) (b) 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 , Dec 2012.

20 Outline Preliminaries Introduction to wideband noise canceling (NC) LNAs and receivers Review of feedback and feedforward models for NC Macro models of MOSFETs and resistors Equivalent models of NC circuits and simulations Conclusions

21 Feedforward Noise Canceling Add a feed forward amplifier to nullify the noise of main amplifier at the output [13]. N m A m Delay (τ 2 ) Y X Delay (τ 1 ) Attenuator (γ 1 ) X 1 A aux Y A Z

22 Feedforward Noise Canceling Add a feed forward amplifier to nullify the noise of main amplifier at the output [13]. N m A m Delay (τ 2 ) Y X Delay (τ 1 ) Attenuator (γ 1 ) X 1 A aux Y A Z γ 1 = 1 A m, X 1 = γ 1 N m Y A = A aux (γ 1 N m ) Y = A m X +N m Z = Y Y A = A m X +N m (1 A aux γ 1 ) If, A aux = 1 γ 1, Z = A m X Noise Canceling Condition is A aux = A m = 1 γ 1

23 Feedback Noise Reduction N 1 X e A m Y β e = X 1+A m β X A m Y β Y = A mx 1+A m β

24 Feedback Noise Reduction N 1 X e A m Y β e = X 1+A m β e = βn m 1+A m β Y = N m 1+A m β N m X A m Y A m Y β β (a) Y = A mx 1+A m β (b)

25 Feedback-Feedforward Noise Canceling e = X 1+A m β βn m 1+A m β A aux N m Y A X A m Z β Y = A mx 1+A m β + N m 1+A m β e = X 1+A m β βn m 1+A m β (3) Y = A mx 1+A m β + N m 1+A m β (4)

26 Feedback-Feedforward Noise Canceling e = X 1+A m β βn m 1+A m β A aux Y A N m X A m Z No N m iff A aux = 1 β β Y = A mx 1+A m β + N m 1+A m β Condition for Noise Cancellation: A aux = 1 β Overall Gain at NC condition: Z X = Y X + Y A X = A m 1+A m β + 1/β 1+A m β = 1 β or A aux

27 Outline Preliminaries Introduction to wideband noise canceling (NC) LNAs and receivers Review of feedback and feedforward models for NC Macro models of MOSFETs and resistors Equivalent models of NC circuits and simulations Conclusions

28 Macro Model of a MOSFET i n v g i g m v out g v s v s (a) (b)

29 Macro Model of a MOSFET in CG configuration i n v g i g m v out g v s v s (a) (b) i n v s g m v s (c)

30 Macro Model of a MOSFET in CS configuration i n v g i g m v out g v s v s (a) (b) i n v g v s g m v s v g g m i n (c) CG configuration (d) CS configuration

31 Macro Model of a Resistor i x = i y i n v x i x i y v y X (a) Y

32 Macro Model of a Resistor i x = i y i n v x i x i y v y X (a) Y i x = i y i x = ( v x ) ( v y )+i n (6) (5)

33 Macro Model of a Resistor i x = i y i n v x X i x = ( v x ) ( v y )+i n i x i n i y v y v x X i x i y Y v y 1 Y (a) (b)

34 Macro Model of a Resistor i x = i y i n v x X i x = ( v x ) ( v y )+i n i x i n i y v y v x i x i y v y Y X Y 1 (a) (b) v x X 1 i x i n i y v y i n 1 Y (c) 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 , May 2014.

35 Macro Model of a Resistor i x = i y i n v x X i x = ( v x ) ( v y )+i n i x i n i y v y v x X i x i y Y v y 1 Y (a) (b) v x X i x i n 1 1 i n i y v y Y v x X i x i y 1 i n i y v y Y (c) (d) 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 , May 2014.

36 Outline Preliminaries Introduction to wideband noise canceling (NC) LNAs and receivers Review of feedback and feedforward models for NC Macro models of MOSFETs and resistors Equivalent models of NC circuits and simulations Conclusions

37 Equivalent Model of a Common Gate LNA Vdd R L v out vin R s i e v e R s g m i n v out R L v e R s v in iout (a) (b) Figure 1: (a) A CG amplifier, and (b) a feedback model of it. v e = 1 1+g m R s v in R s/r L 1+g m R s v n v out = g mr L 1+g m R s v in g m R s v n, where v n = i n R L

38 Equivalent Model of a NC Common Gate LNA A aux v e g m i n v out v out v in R s i e R s R L Noise canceling condition: A aux = R L R s

39 Simulation of CG NC-LNA V dd = 1.8 V 350 Ω out p 80µ 0.18µ β = R s R L = 1 7 v out out n 50 Ω v e A aux VCVS v in 2.5 ma β = R s R L = 1 7 A aux = 1 β = 7

40 Simulation of CG NC-LNA Noise at v out in nv/sqrt(hz) A aux = 1 β = Auxiliary Amplifier Gain (A aux ) (a) 50 MHz 100 MHz 500 MHz 1 GHz Voltage Gain v out = out p out n out p v out vin = 1 β = M 100M 1G 10G Frequency (Hz) (b)

41 Equivalent Model of the NC RSF LNA 1 v out i n v in R s v e R s g m 1 v out 1 R s 1 v e = 1+g m R s v in + R s/ 1+g m R s v n v out = 1 g m 1+g m R s v in + 1+R s/ 1+g m R s v n

42 Simulation of RSF NC-LNA V dd = 1.8 V β = R s = ma 50 Ω 250 Ω v in v e 160 µ 0.18 µ v out 70 µ 0.18 µ v out VCVS Aaux NC condition: A aux = 1+ 1 β = 6 Gain of amplifier at NC = 1/β = 5

43 Simulation of RSF NC-LNA (Hz) Noise voltage in nv/ Noise cancellation occurs at A aux = 1+ 1 β instead of 1 β due to the bidirectional nature of. A aux = 1+ 1 β = MHz MHz 1 GHz Gain of the auxiliary amplifier ( A aux ) (a) v out/v in v out /v in Voltage Gain v out v in = 1 β = 5 β = R s = M 100M 1G 10G Frequency (Hz) (b)

44 Equivalent Model of a Wideband Receiver R in R m R s v e out n v in (a) i n r m = R m π due to the mixer gain v e 1 R in out n R s R in r m v in (b) 1 v e = 1+ R s v in R s/r m 1+ R s R in R in v n out n = r m/r in 1+ R s v in R s v n, where v n = i n r m R in R in

45 Simulation of the Wideband NC Receiver 250 Ω g m VCCS g m = 20mS I aux VCVS out p 250 Ω v out 50 Ω 50 Ω v in I m VCVS out n

46 Simulation of a Wideband NC Receiver Output noise voltage in nv/ Hz Voltage gain PNOISE analysis β = πr s R m = π 5 A aux = 1 β = 5 π 1.59 Auxiliary path gain (A aux ) (a) v out v in = 1 β = 5 π = 1.59 Relative input frequency (Hz) v out /v in out n /v in out p v in = A m 1+A m β = 2.5 π = K 10K 100K 1M 10M 100M200M (b)

47 Outline Preliminaries Introduction to wideband noise canceling (NC) LNAs and receivers Review of feedback and feedforward models for NC Macro models of MOSFETs and resistors Equivalent models of NC circuits and simulations Conclusions

48 Conclusions Shown that the NC is a feedback-feedforward technique In a NC amplifier/receiver, if the feedback factor of the main amplifier/receiver is β, then the gain of the auxiliary amplifier/receiver (A aux ) needed to cancel the noise of the main amplifier/receiver is equal to 1/β Under this noise canceling condition, the overall gain of the NC-wideband amplifier/receiver is equal to 1/β Indrajit Das, Nagarjuna Nallam, The Role of Feedback in Noise Canceling LNAs and Receivers, to appear in IEEE Micro. Mag.

49 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 , Feb [ 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 , March [ 4 ] C.F. Liao and S.I. Liu, A broadband noise-canceling CMOS LNA for GHz UWB receivers, IEEE J. Solid-State Circuits, vol. 42, no. 2, pp , Feb [ 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 , May [ 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 , June [ 7 ] 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 , Dec [ 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 , June [ 9 ] C. McNeilage, E. Ivanov, P. Stockwell, and J. Searls, Review of feedback and feedforward noise reduction techniques, in Frequency Control Symposium, Proceedings of the 1998 IEEE International, May 1998, pp [ 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 , May 2014.

50 Notes

A Volterra Series Approach for the Design of Low-Voltage CG-CS Active Baluns

A Volterra Series Approach for the Design of Low-Voltage CG-CS Active Baluns Shan He and Carlos E. Saavedra Gigahertz Integrated Circuits Group Department of Electrical and Computer Engineering Queen s