Post on 13-Jan-2022
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IN5240 RF Amplifier Part 3
Sumit Bagga*, Torleif Skår and Dag T. Wisland**
*Staff IC Design Engineer, Novelda AS**CTO, Novelda AS
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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
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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
IN5240: Design of CMOS RF-Integrated Circuits, Dag T. Wisland and Sumit Bagga
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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! ≫ "
#$Ω and minimum
gate resistance, 𝑅%• Cover bandwidth specified by standard• Conjugate matching at the input
IN5240: Design of CMOS RF-Integrated Circuits, Dag T. Wisland and Sumit Bagga
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LNA Topologies
IN5240: Design of CMOS RF-Integrated Circuits, Dag T. Wisland and Sumit Bagga
Common-Source (CS) Common-Gate (CG) Broadbandw/ CG (Cascode)
Resistive feedback
Inductive load
Inductive degeneration
w/ CG
Inductive load
Feedback
Feedforward (Boosted CG)
Noise-cancelling
Reactive cancelling
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Performance Metrics
• ‘Dominant’ input device suppresses noise contributed subsequent blocks à ↑ gain– Trade-off gain for linearity
• Optimize input device for lowest noise figure– NF < 2 dB à CS-stage w/ 𝑔! ≫ "
#$Ω and minimum
gate resistance, 𝑅%• Cover bandwidth specified by standard• Conjugate matching at the input
IN5240: Design of CMOS RF-Integrated Circuits, Dag T. Wisland and Sumit Bagga
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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.
IN5240: Design of CMOS RF-Integrated Circuits, Dag T. Wisland and Sumit Bagga
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Small-Signal Model
IN5240: Design of CMOS RF-Integrated Circuits, Dag T. Wisland and Sumit Bagga
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CS, CG and CD
IN5240: Design of CMOS RF-Integrated Circuits, Dag T. Wisland and Sumit Bagga
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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"
IN5240: Design of CMOS RF-Integrated Circuits, Dag T. Wisland and Sumit Bagga
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Transformer Layout contd.
Monolithic Transformers for Silicon RF IC Design, John R. Long, 2000
IN5240: Design of CMOS RF-Integrated Circuits, Dag T. Wisland and Sumit Bagga
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Transformer Model contd.
𝑣𝑜 =𝑘2𝐿1𝐿1
𝐿2𝑀 𝑣𝑖 =
𝑘2𝐿2𝑀 𝑣𝑖 =
𝑘2𝐿2𝑘 𝐿1𝐿2
𝑣𝑖 = 𝑛𝑘𝑣!
IN5240: Design of CMOS RF-Integrated Circuits, Dag T. Wisland and Sumit Bagga
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Transformer Model
IN5240: Design of CMOS RF-Integrated Circuits, Dag T. Wisland and Sumit Bagga
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
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Z Parameters
IN5240: Design of CMOS RF-Integrated Circuits, Dag T. Wisland and Sumit Bagga
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Transformer Layout
IN5240: Design of CMOS RF-Integrated Circuits, Dag T. Wisland and Sumit Bagga
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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
IN5240: Design of CMOS RF-Integrated Circuits, Dag T. Wisland and Sumit Bagga
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Resistive-Feedback Preamplifier
L 50 Ω input match, low NF and low Pdc
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])
IN5240: Design of CMOS RF-Integrated Circuits, Dag T. Wisland and Sumit Bagga
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2-Stage LNA w/ Idc Reuse
gm-boosting input stage and transimpedance amplifier
INF5481: RF kretser, teori og design Dag T. Wisland
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])
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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
IN5240: Design of CMOS RF-Integrated Circuits, Dag T. Wisland and Sumit Bagga
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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
IN5240: Design of CMOS RF-Integrated Circuits, Dag T. Wisland and Sumit Bagga
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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+
IN5240: Design of CMOS RF-Integrated Circuits, Dag T. Wisland and Sumit Bagga
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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
IN5240: Design of CMOS RF-Integrated Circuits, Dag T. Wisland and Sumit Bagga
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Basic CG-LNA
NF ≥ 2 dBZi ≅ 1/gm
IN5240: Design of CMOS RF-Integrated Circuits, Dag T. Wisland and Sumit Bagga
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Feedforward gm-Boosting
IN5240: Design of CMOS RF-Integrated Circuits, Dag T. Wisland and Sumit Bagga
[Liscidini, ISSCC, 2015]
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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
IN5240: Design of CMOS RF-Integrated Circuits, Dag T. Wisland and Sumit Bagga
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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
IN5240: Design of CMOS RF-Integrated Circuits, Dag T. Wisland and Sumit Bagga
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Feedback & Feedforward
IN5240: Design of CMOS RF-Integrated Circuits, Dag T. Wisland and Sumit Bagga
• [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)
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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
IN5240: Design of CMOS RF-Integrated Circuits, Dag T. Wisland and Sumit Bagga
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Trifilar Design
P1P2 P3
P4
P5P6
IN5240: Design of CMOS RF-Integrated Circuits, Dag T. Wisland and Sumit Bagga
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S21 and S11 in 55 nm CMOS
IN5240: Design of CMOS RF-Integrated Circuits, Dag T. Wisland and Sumit Bagga
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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: Design of CMOS RF-Integrated Circuits, Dag T. Wisland and Sumit Bagga