Th3G-6

A 20.8–41.6-GHz Transformer-Based

Wideband Power Amplifier with 20.4-dB Peak

Gain Using 0.9-V 28-nm CMOS Process

C. Wang1, Y. Chen1, J. Tsai2, T. Huang1

1Graduate Institute of Communication Engineering,

National Taiwan University, Taipei, Taiwan2Department of Electrical Engineering,

National Taiwan Normal University, Taipei, Taiwan

Th3G-6

Outline

• Motivation

• Reported Works

• Circuit Design

• Experimental Results

• Summary

2

Th3G-6

Outline

• Motivation

• Reported Works

• Circuit Design

• Experimental Results

• Summary

2

Th3G-6

• MMW frequency range for 5G NR: 24.25 – 52.6 GHz (FR2)

4

Motivation

24 29 37 52 GHz

Multiple

T/RXs

Multiple

T/RXs

Wideband T/RX

Th3G-6

• Wideband MMW PA

–Allows flexibility for spectrum utilization

–Simplifies the assembly process for multi-band transmitters

–Lower costs of front-ends components

• PAs consume most of the power in the transmitter system

–High efficiency

5

Motivation

Th3G-6

Outline

• Motivation

• Reported Works

• Circuit Design

• Experimental Results

• Summary

2

Th3G-6

• Procress: 45-nm SOI CMOS

• Topology: Mixed-Signal Doherty

• Small-signal gain BW3dB:22.35-34.5 GHz

• Operating frequency: 27 GHz

• Gain: 19.1 dB

• Psat: 23.3 dBm

• PAEMAX: 40.1%

• Core size: 0.52 mm2

7

Reported Works I

F. Wang, T. Li and H. Wang, "4.8 A highly linear super-resolution mixed-signal Doherty power

amplifier for high-efficiency mm-wave 5G multi-Gb/s communications," 2019 IEEE International

Solid- State Circuits Conference - (ISSCC), San Francisco, CA, USA, 2019, pp. 88-90

Th3G-6

• Procress: 28-nm CMOS

• Topology: 2 stage Class-AB CS

• Small-signal gain BW3dB:29-57 GHz

• Operating frequency: 30 GHz

• Gain: 20 dB

• Psat: 16.6 dBm

• PAEMAX: 24.2%

• Core size: 0.16 mm2

8

Reported Works II

M. Vigilante and P. Reynaert, “A wideband class-AB power amplifier with 29–57-GHz AM–PM compensation

in 0.9-V 28-nm bulk CMOS,” IEEE J. Solid-State Circuits, vol. 53, no. 5, pp. 1288–1301, May 2018

Th3G-6

Outline

• Motivation

• Reported Works

• Circuit Design

• Experimental Results

• Summary

2

Th3G-6

• Smaller transistor cell

– higher gain and PAE

• Deep-class AB bias

– lower quiescent Pdc

– linear operation close to Psat

10

PA Architecture

0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9-150

-100

-50

0

50

100

150

200

Tra

ns

co

nd

ucta

nce

[m

A/V

]

VGS

[V]

gm1

gm2

gm3

S

M1

M1

CPAD

Vg,DACn,DA

Cn,DA

Vd,DA

M2

M2

Vg,PACn,PA

Cn,PA

Vd,PA

G

G

S

CPAD

G

G

RFin RFout

Driver Stage:

M1 = 5 × ( 1 m × 32f )

Power Stage:

M2 = 12 × ( 1 m × 32f )

Cn,DA = 35 fF

CPAD = 47 fF

Cn,PA = 91 fF

Th3G-6

• Capacitive Neutralization, Cn = 91fF

• MSG/MAG turning point move from 100 GHz to 10 GHz

• Higher gain and stability

11

Neutralization Technique

0 20 40 60 80 100 1200

10

20

30

40

50

MS

G /

MA

G [

dB

]

Frequency [GHz]

w.i. Cn

w.o. Cn

Cn Cn

Vin+ Vin

-

Vout-

Vout+

S. Shakib, H. Park, J. Dunworth, V. Aparin and K. Entesari, "A highly efficient and linear power amplifier for 28-GHz 5G phased array radios in 28-nm

CMOS," IEEE Journal of Solid-State Circuits, vol. 51, no. 12, pp. 3020-3036, Dec. 2016.

Th3G-6

• Transformer with two coupled resonant capacitors

• Calibration-free

• Cpad= 47 fF, Cparasitic= 477 fF

12

Output Broadband Matching

M1

M7

M8

M9

AP

M3

：

： ：

Zopt*

RFoutCPAD

GND (M1 to M7)

GND

(M1 to M8)

VD,PA

VD,PA

io+

io-

GND (M1 to M3)

L1 (M9+AP)

Z-axis

Z-axis

Cpar

RFout

(50Ω )CPADVd,PA

Cparasitic

io+

io-

L1 L2

L2 (M8+M7)

Th3G-6

Outline

• Motivation

• Reported Works

• Circuit Design

• Experimental Results

• Summary

2

Th3G-6

• The core area is 0.1 mm2

— 500μm × 200μm

• Output matching with AP layer

— darker metal

• TSMC 28-nm CMOS process

14

Chip Micrograph

500μm

200μm

Th3G-6

• DC condition

– Bias: Vg,DA = 0.38 V, Vg,PA = 0.32 V

– Supply voltage: VDD= 0.9 V

– Pdc: 39.6 mW

• S-parameters

– Peak gain: 20.4 dB @ 23 GHz

– 3-dB bandwidth: 20.8 – 41.6 GHz

(66.7% fractional bandwidth)

15

Simulation & Measured S-parameters

0 10 20 30 40 50-40

-30

-20

-10

0

10

20

30

40

S-p

ara

me

ters

[d

B]

Frequency [GHz]

Sim. S11

Meas. S11

Sim. S21

Meas. S21

Sim. S22

Meas. S22

Th3G-6

• PAEMAX stays above 25% from 22 to 41 GHz

• Psat > 15dBm from 23 to 38.5 GHz

16

Measured CW Performance

20 22 24 26 28 30 32 34 36 38 40 42 448

10

12

14

16

18

20

22

24

PSAT

PAEMAX

OP1dB

Frequency [GHz]

Po

ut [

dB

m]

0

5

10

15

20

25

30

35

40

PA

EM

AX [%

]

Th3G-6

• Modulated Signal

– 64-QAM OFDM

– Bandwidth: 100MHz

– PAPR: 9.7 dB

• Under EVM of -25 dB– 8.5% PAE and 7.2 dBm Pout

@ 23 GHz

– 8.8% PAE and 6.9 dBm Pout

@ 41 GHz

17

Modulation Measurements

EVM = -25.1 dB

BW = 100 MHz

EVM = -25.4 dBc

BW = 100 MHz

23 GHz

41 GHz

Th3G-6

Ref. This work TCASI’19 IMS’19 JSSCC’18 RFIC’18 ISSCC’19 RFIC’18

Tech. 28-nm CMOS 65-nm CMOS 65-nm CMOS 28-nm CMOS 90-nm CMOS45-nm SOI

CMOS

45-nm SOI

CMOS

Topology2 stage

Class-AB CS

1 stage

Class-F CS

2 stage

Class-AB CS

2 stage

Class-AB CS

1 stage

Cascode

Mixed-Signal

Doherty

1 stage

Class-F/F-1

Cascode

Small-signal gain BW3dB

[GHz]20.8-41.6 25-35 33-41 29-57 22.5-32 22.35-34.5 25.9-43.7

Small-signal gain BW3dB

[%]66.7 33 21.6 65 34.9 42.7 51

VDD

[V]0.9 1.1 1.2 0.9 2.4 2 2

Operation Frequency

[GHz]23/25/30/41 30 39 30/40 24/28 27 28/37/39

Gain [dB] 20.4/19.9/17.8/17.6 10 14.4 20*/20.5* 17.4/16.3 19.1 11.4/10.7/10.5

Psat [dBm] 15.1/15.5/16.1/14.7 14.75 20.7 16.6/15.9 25.6/26 23.3 18.9/18.9/18.9

PAEMAX [%] 30.1/35.3/28.8/26.2 44.5* 35 24.2/18.4 32.8/34.1 40.1 43.2/37/36

OP1dB [dBm] 12.4/12.7/9.8/13 13.2 20.2 13.4/11.1 23.6/23.2 22.4 16.9/17/17.4

Pdc [mW] 39.6 NA NA 170.1 1035 NA 48

Core Area [mm2] 0.1 0.12 0.21 0.16 0.4 0.52 0.14

18

Comparison

Th3G-6

Outline

• Motivation

• Reported Works

• Circuit Design

• Experimental Results

• Summary

2

Th3G-6

• Broadband PA implementation

–Proper biasing

–Broadband output-matching

• Performance

–20.4 dB peak gain

–20.8 to 41.6 GHz 3-dB small signal bandwidth

–PAEMAX > 25% from 22 GHz to 41 GHz

20

Summary

Th3G-6

Thanks for your attention!

21

Th3G-6

[1] S. N. Ali, P. Agarwal, S. Gopal, S. Mirabbasi and D. Heo, "A 25–35 GHz neutralized continuous Class-F

CMOS power amplifier for 5G mobile communications achieving 26% modulation PAE at 1.5 Gb/s and

46.4% peak PAE," in IEEE Transactions on Circuits and Systems I: Regular Papers, vol. 66, no. 2, pp.

834-847, Feb. 2019

[2] S. Shakib, M. Elkholy, J. Dunworth, V. Aparin and K. Entesari, "A Wideband 28-GHz Transmit–Receive

Front-End for 5G Handset Phased Arrays in 40-nm CMOS," in IEEE Transactions on Microwave Theory

and Techniques, vol. 67, no. 7, pp. 2946-2963, July 2019.

[3] M. M. R. Esmael, M. A. Y. Abdalla and I. A. Eshrah, "A 19-43 GHz Linear Power Amplifier in 28nm Bulk

CMOS for 5G Phased Array," 2019 IEEE Topical Conference on RF/Microwave Power Amplifiers for Radio

and Wireless Applications (PAWR), Orlando, FL, USA, 2019, pp. 1-3.

[4] F. Wang, T. Li and H. Wang, "4.8 A highly linear super-resolution mixed-signal Doherty power amplifier

for high-efficiency mm-wave 5G multi-Gb/s communications," 2019 IEEE International Solid- State Circuits

Conference - (ISSCC), San Francisco, CA, USA, 2019, pp. 88-90

[5] M. Vigilante and P. Reynaert, “A wideband class-AB power amplifier with 29–57-GHz AM–PM

compensation in 0.9-V 28-nm bulk CMOS,” IEEE J. Solid-State Circuits, vol. 53, no. 5, pp. 1288–1301,

May 2018

22

References

Th3G-6

[6] Y. Chen, T. Tsai, J. Tsai and T. Huang, "A 38-GHz-Band Power Amplifier with Analog Pre-distortion for

1600-MHz Transmission Bandwidth 64-QAM OFDM Modulated Signal," 2019 IEEE MTT-S International

Microwave Symposium (IMS), Boston, MA, USA, 2019, pp. 312-315.

[7] W.-C. Huang, J.-L. Lin, Y.-H. Lin, and H. Wang, “A K-band power amplifier with 26-dBm output power

and 34% PAE with novel inductance-based neutralization in 90-nm CMOS,” in Proc. IEEE Radio Freq.

Integr. Circuits Symp. (RFIC), Jun. 2018, pp. 228–231.

[8] T.-W. Li and H. Wang, “A continuous-mode 23.5-41 GHz hybrid class-F/F-l power amplifier with 46%

peak PAE for 5G massive MIMO applications,” in Proc. IEEE Radio Freq. Integr. Circuits Symp. (RFIC),

Jun. 2018, pp. 220–230.

[9] D. Zhao and P. Reynaert, "A 60-GHz Dual-Mode Class AB Power Amplifier in 40-nm CMOS," in IEEE

Journal of Solid-State Circuits, vol. 48, no. 10, pp. 2323-2337, Oct. 2013.

[10] Y. Zhang and P. Reynaert, “A high-efficiency linear power amplifier for 28 GHz mobile communications

in 40 nm CMOS,” in Proc. IEEE Radio Freq. Integr. Circuits Symp. (RFIC), Jun. 2017, pp. 33–36.

23

References