in5240 rf amplifier part 3

Institutt for Informatikk

IN5240 RF Amplifier Part 3

Sumit Bagga*, Torleif Skår and Dag T. Wisland**

*Staff IC Design Engineer, Novelda AS**CTO, Novelda AS


Direct-RF Receiver

Receiver comprises high-pass filter (HPF) for interference rejection, impedance and noise-matched low-noise amplifier (LNA), and high-speed analog-to-digital converter (ADC)

IN5240: Design of CMOS RF-Integrated Circuits, Dag T. Wisland and Sumit Bagga

LNAHPF

ADC


Design Aspects

• Specifications– Gain, noise figure, bandwidth, impedance and noise

match, linearity, stability, group delay and power consumption

• Configuration– Single-ended, single-ended to differential, fully

differential or pseudo-differential

• RF design, single-stage amplifier are preferred– Common-source or common-gate



Performance Metrics

• ‘Dominant’ input device suppresses noise contributed subsequent blocks à ↑ gain– Trade-off gain for linearity

• Optimize input device for lowest noise figure– NF < 2 dB à CS-stage w/ 𝑔! ≫ "

#$Ω and minimum

gate resistance, 𝑅%• Cover bandwidth specified by standard• Conjugate matching at the input



LNA Topologies


Common-Source (CS) Common-Gate (CG) Broadbandw/ CG (Cascode)

Resistive feedback

Inductive load

Inductive degeneration

w/ CG

Inductive load

Feedback

Feedforward (Boosted CG)

Noise-cancelling

Reactive cancelling


Performance Metrics

• ‘Dominant’ input device suppresses noise contributed subsequent blocks à ↑ gain– Trade-off gain for linearity

• Optimize input device for lowest noise figure– NF < 2 dB à CS-stage w/ 𝑔! ≫ "

#$Ω and minimum

gate resistance, 𝑅%• Cover bandwidth specified by standard• Conjugate matching at the input



ECE145A/ECE218A AMPLIFIER DESIGN

12/14/07 6 Prof. Stephen Long, ECE/UCSB

Ref. G. Gonzalez, Microwave Transistor Amplifiers, Analysis and Design, Second Ed., Wiley, 1997.



Small-Signal Model



CS, CG and CD



CG Power-to-Voltage Amplifier

• Inductive loading à tuned parallel resonance – Frequency selectivity to remove

out-of-band interferers– Current magnification (𝑸 & 𝑰𝑳)– No voltage drop

𝑍! ≈ 1/𝑔"



Transformer Layout contd.

Monolithic Transformers for Silicon RF IC Design, John R. Long, 2000



Transformer Model contd.

𝑣𝑜 =𝑘2𝐿1𝐿1

𝐿2𝑀 𝑣𝑖 =

𝑘2𝐿2𝑀 𝑣𝑖 =

𝑘2𝐿2𝑘 𝐿1𝐿2

𝑣𝑖 = 𝑛𝑘𝑣!



Transformer Model


Monolithic Transformers for Silicon RF IC Design, John R. Long, 2000

𝑛 =𝑣'𝑣(=𝑖(𝑖'= 𝑙'/𝑙(

𝑘 =𝑀𝑙'/𝑙(

𝑛/𝑘 = 𝑙'/𝑀


Z Parameters



Transformer Layout



Broadband LNA w/ LC-Ladder

Cascode gain cell, input filter, and output buffer

A 1.2 V Reactive-Feedback 3.1–10.6 GHz Low-Noise Amplifier in 0.13 m CMOS, M. Reiha, ’07 (Ref.: [4-6])

A. Bevilacqua, A. Ismail, F. Lee



Resistive-Feedback Preamplifier

L 50 Ω input match, low NF and low Pdc




2-Stage LNA w/ Idc Reuse

gm-boosting input stage and transimpedance amplifier

INF5481: RF kretser, teori og design Dag T. Wisland



Negative Current Feedback CS-LNA

β = nZi ≅ n/gm

T1 is non-inverting. Current sensed via T1,p is negatively fed back and applied in parallel at the input via T1,s

T1,s

RFi M1

RL

RFo

VDD-ifb

T1,p



Gm = gm(1+nk); nk < 1Zi ≅ n/(Gm)

T1 is inverting. Current sensed via T1,p is negatively fed back and applied in parallel at the input via T1,s

T1,s

RFi M1

T1,p

RL

RFo

VDD-ifb

+vin-

-vin/n+

A 1.2 V Reactive-Feedback 3.1–10.6 GHz Low-Noise Amplifier in 0.13 μm CMOS, M. Reiha, ‘07

gm-Boosted CS-LNA



gm-Boosted CS-LNA w/ Trifilar

Gm = gm(1+nk)Zi ≅ n/(Gm)

T1 is inverting. Assume kpt ≅ 0 and kps & kst ≅ 1. Total gate-source voltage is ≅ vin + vin/n2 - (-vin/n1)

T1,s

RFi

T1,t

M1

T1,p

RL

RFo

VDD-ifb

+vin-

- vin/n2 +-

vin/n1+



gm-Boosted CS-LNA w/ Auto-Transformers (AT)

Gm = gm(1+n2k2)Zi ≅ n1,2/(Gm)

2 ATs w/ T2 > T1- +V feedforward- -I feedback

T2,s

RFi,+

T2,pM1

T1,pT1,s



Basic CG-LNA

NF ≥ 2 dBZi ≅ 1/gm



Feedforward gm-Boosting


[Liscidini, ISSCC, 2015]


Gm-Boosted CG-LNA

Gm = gm(1+nk)Zi ≅ 1/(gm(1+nk))

Gm-boosted common-gate LNA and differential colpitts VCO/QVCO in 0.18 µm CMOS, X. Li, ‘05



Positive Current Feedback CG-LNA

β = 1-(k/n)Zi ≅ 1/(gm(1-k/n))

Common Gate Transformer Feedback LNA in a High IIP3 Current Mode RF CMOS Front-End, A. Liscidini, ‘06



Feedback & Feedforward


• [Li, 2005] – 𝑔"-boosted CG-LNA with transformer feedforward loop– Feedforward factor is (1 + 𝑘𝑛), where n is the turns

ratio and k is the coupling coefficient

• [Liscidini, 2005] – CG-LNA with positive transformer feedback loop– Feedback factor is (1 − 𝑘/𝑛)


Trifilar CG-LNA

LP-LS: Inv.LP-LT: Non-Inv.LP-LT: Inv.(stability, kT,S à 0)

Zi ≅ 1/(gm(1+nP,SkP,S+nT,SkT,S)(1-kT,P/nT,P))

P1

P2

P3

P4

P5

P6



Trifilar Design

P1P2 P3

P4

P5P6



S21 and S11 in 55 nm CMOS



Key References

1. A. M. Niknejad, EECS 142 and 2422. A. Liscidini, “Fundamentals of Modern RF

Receivers,” ISSCC 20153. N. Andersen, “A 118-mW Pulse-Based Radar

SoC in 55-nm CMOS for Non-Contact Human Vital Signs Detection,” JSSC, 2017


in5240 rf amplifier part 3

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