Broadband Design Techniques and Technology for

Broadband Design Techniques and Technology for Future Wireless and Wireline Applications Kevin W. Kobayashi, Karthik Krishnamurthy, Ramakrishna Vetury, Ying McCleary, Rainer Hillermeier, and Jeff B. Shealy

Outline

• Introduction • Evolution of the RF Darling Amplifer • Design Technology • New Technology

• 100 Gbps Fiber Optics • Broadband Linear GaN Design • SDR LNA & PA • CATV amplifer

• Summary

Future Front-End Requirements Design Perspective Linearity Power/Efficiency Spectral & Energy Efficiency Access Higher Data Rate Dynamic Range

Spectral Efficiency Access

Bandwidth Modulation BW

Sensitivity Network Reach

Darlington’s Evolution ORIGIN Darlington Invention [1] (1953)

1953

Si-BJT Products [4] (~1981-1983)

1980 1981 1989

1995

1999 2000

2005 2006

2007 2009 2010

fT-doubler Invention [2] (1980)

Analog Period (1953-1980)

Leap to RF

RF Period (1980-2009)

RF + (> 2010)

Sidney Darlington 1906-1997 [1]

 2

Bell Labs (1953) Pat. No. 2,663,806

Tektronix Darlington Amplifer [2] Pat. No. 4,236,119 (1980) “fT Doubler” C

Enhancement 2  2 B

1 2

fT 1.5 fT d

12dB/Oct  6 dB/Oct Less excess Phase  More stable E

The LEAP from Analog to RF Avantek MODAMP (1981-1983)

MSA0735(Avantek) [4]


1953


1980 1981 1989


Analog Leap to RF Period (1953-1980)

1995

1st GaAs Demo [5,6]

Leap to GaAs

1999 2000

2005 2006

2007 2009 2010

1st GaAs Products

RF Period (1980-2009)

RF + (> 2010)

The LEAP to GaAs HBT (1991-1995) How do you make products from a high cost R&D technology?

Shrink die 1. Compact Layout 2. Backside VIA

Offer superior performance 1. Higher fT-BVceo 2. High Jc

RIE VIA

INPUT

OUTPUT

~310 um


1953

1980 1981 1989


Leap to RF


InGaP Products


1st GaAs Demo [5,6]

1st SiGe Products [8]

1995

1st GaAs Products [7]

Leap to GaAs

1999 2000

st 1st E-mode 1 GaN PHEMT MMIC Products Demo [14] [11]

2005 2006

Active-Bias [10] 1st GaN Demo [9] (UCSB)

2007 2009 2010

Active Dynamic FB [15]

RF Design Evolution

RF Period (1980-2009)

RF + (> 2010)

Self-Biased Darlington (2005) 30-40% DC power savings

Self-Bias Darlington

E-mode PHEMT Darlingtons (2006)

+ -

-

+

-

+

E-mode PHEMT enables positive self-bias

Vgs~ +0.6V @ 80mA/mm

Darlington I-V Comparison GaAs E-PHEMT vs. InGaP HBT 180

Idd_PHEMT (mA) Icc_InGaP (mA)

160

Lower Knee 140 Voltage 120 E-PHEMT 100

InGaP HBT

80 60 40 20 0

Vgs ~ 0.6V Vbe ~ 1.4V

0

1

2

3 VCE (V) VDS (V)

4

5

6

IP3-BW Comparison – GaAs E-PHEMT vs. InGaP HBT

IP3 (dBm)

50 40

5V-90mA PHEMT Darlington [11]

30 5V-80mA InGaP HBT Darlington [10]

20 10

HBT Parasitic Effect -Feedback Phase

0 0

2

4 6 8 Frequency (GHz)

10

E-mode PHEMT improves IP3-BW

Linearized Darlington Cascode (2006)

Darlington Cascode

180° (ideal at DC)

0°

ZVref () Optimize FB phase High IP3

Linearized Darlington Cascode (2006)

IP3: Darlington Cascode vs. Conventional 35 Linearized Darlington Cascode

30 IP3 (dBm)

25 Conventional

20 15 10

(1.8X improvement in IP3-BW)

5 0 0

2

4

6 8 10 12 Frequency (GHz)

14

16

Dynamic Feedback Linearized Darlington (2007)

Orthogonal DFB Tuning

Ib

Dynamic Feedback Linearized Darlington (2007)

70

140

60

120

50

100

IM3

40

80

Dynamic Bias

30

60

Conventional

Icc

20

40

10

20

0

0 -10

-5

0

5

10

15

RF Power (dBm)

 LFOM= IP3/Pdc ~ 55.4:1 @ 1 GHz ~ 26.9:1 @ 2 GHz

20

Icc (mA)

IM3 (dBc)

Dynamic Bias vs Conventional

First GaN HEMT MMIC (2007) Darlington-Cascode - P1dB > 1Watt

Darlington Cascode

IP3, P1dB, Psat (dBm)

0.2um GaN HEMT MMIC fT~60GHz, BVgd ~ 60V

50

20V (350mA)

45

IP3

40 35

Psat

30

P1dB

25 20 0

D-MODE GaN

1

2 3 Frequency (GHz)

 (IP3-P1dB) ~ 11-12 dB (3-Octaves)

4

Summary of RF Darlington Linear Efficiency 60 DYNAMIC FEEDBACK InGaP Darlington [15]

IP3/Pdc LFOM ratio

50 40

InGaP HBT [10]

30 20

E-PHEMT [13] InGaP HBT [10]

10

E-PHEMT [11] GaN PHEMT [14]

0 0

1

2 Frequency (GHz)

3

4


1953

1980 1981 1989


Leap to RF


InGaP Products


1st GaAs Demo [5,6]

1st SiGe Products [8]

1995

1st GaAs Products [7]

Leap to GaAs

st 1st E-mode 1 GaN PHEMT MMIC Products Demo [14] [11]

High Power E-mode GaN

1999 2000

2005 2006

Active-Bias [10] 1st GaN Demo [9] (UCSB) RF Design Evolution

RF Period (1980-2009)

2007 2009 2010

Active Dynamic FB [15]

Low Voltage (3V) (SiGe, EPHEMT, InP,BiFET)

Next GEN

RF + (> 2010)

Outline • Introduction • Evolution of the RF Darlington Amplifier – • Design Techniques • New Technology • 100 Gbps Fiber Optics • Broadband Linear GaN Design • SDR LNA & PA • CATV amplifier • Summary

100Gbps Fiber Optic Linearity

•Existing 50GHz ITU Grid •Tolerance fiber impairment •Lower Cost Semi’s (silicon)

4 x 28 Gbps PM-QPSK- coherent OIF

Bandwidth SiGe CMOS

Sensitivity

4 x 25 Gbps 40 Gbps (4 x ) IEEE 802.3ab

InP GaAs

100 Gbps SERIAL (OOK)

4 x 28 Gbps PM-QPSK Coherent Receiver

optical signal

PBS

90 degree hybrid

TIA

ADC

TIA

ADC

Linear Balanced TIA

optical LO

BS

90 degree hybrid

TIA

ADC

TIA

ADC

SiGe

SiGe BiCMOS

DSP

100G Coherent RX has the most challenging electronic requirements: Linear TIA’s and high speed 28 GSPS ADC’s

Linear Dual-Input TIA with AGE for Coherent 100G VCC

Vee

CVD

RSSI

CVD

CAGC DET O/B

AGC

Peak Detector

Vref

IN

Linear Preamp

VGA

VGA

VGA

O/B

Out

OC Offset cancellation

VCC

Vee

Q1

Q2

Linearity and Dynamic Range are Key Performance Metrics

Linearity: Total Harmonic Distortion

Vout (SE)

THD

8

300

Vout (mV)

THD (%)

Vin=50mV 6

THD = 5%

4

Vout > 290mV (THD < 5%)

280 260 240

2 220

Vin=50mV 0

0

200

400

600

Vinput (mV)

800

200 0

200

400

600

800

Vinput (mV)

Linearity: Total Harmonic Distortion (THD) < 5%, Dynamic Range > 20 dB

• Pros • Simple (serial, ook) • Pd + TIA Integration (OEIC) • InP and SiGe performance feasible, mature (Serdes)

Gain & Return-Loss (dB)

100Gbps SERIAL(OOK) R&D outlook InP DHBT TIA

20

Gain

10 0 -10 -20 -30 0

• Cons

S22

S11

10

20

30

40

50

60

70

80

90 100 110

Frequency (GHz)

• Grid > 50 GHz • Fiber impairments (CD, PMD) • Short reach • Electronics costly? Maybe not. • TX optical modulator 100G speed?

Presently in the R&D investigation stage for niche applications

Outline • •

• •

•

Introduction Evolution of the RF Darlington Amplifier – • Design Techniques • New Technology IC Linearization for 40 & 100 Gbps Fiber Optics Broadband Linear GaN Design • SDR LNA & PA • CATV amplifier Summary

GaN Front-End Multi-Octave BW Applications Linearity Power/Efficiency Ext. 1 GHz BW Digital channels energy savings

Multi-carrier Multi-mode/format CATV

Frequency agility Multi-modes Adaptive

SDR Radios

Bandwidth Multi-Decade

Sensitivity Network Reach

Software Defined Radio Concepts (SDR)

LNA

GaN PA

Super heterodyne

ADC

DSP

DAC

demod equalization detection rake-RX DPD

Frequency Translation linear mixer NQ filter LO/VCO VGA

GaN HEMT Provides Linearity, Low Noise, and Power Efficiency due to inherent material properties

GaN MMIC LNA Noise Capability State-of-the-Art GaN MMIC LNA Noise Figure 3 [27] HRL

Noise Figure (dB)

2.5 [29] NGST

2 [30] NGST

1.5

[35] NG

0.5

[34] CREE [31] NGST

1

[28] UCSB

[32] SIRENZA-NGST

< 0.2dB [33] RFMD-NG

0 0

2

4 Frequency (GHz)

6

8

T=-30C GaN HEMT’s material properties enable SOA multi-octave low noise over octave bandwidths

S- & C-Band LNA Dynamic Range SDR Multi-decade

OIP3 (dBm)

GaN [32-33]

OIP3 vs. Noise Figure for S- & C-Band Commercial LNA’s and Discretes 55 HBT

50

HFET FET

HFET

45 40 35

PHEMT

30

Low Noise

25 0

1

2

3

4

5

6

7

8

Noise Figure (dB)

GaN HEMT can provide ultra wide dynamic range over a multidecades of BW!

MHz – Microwave GaN PA’s MHz - Microwave GaN Power Amplifiers Circuit Topology

PAE (%) Small Supply Output Pout Signal ImplemeVoltage power measured Bandwidth (measured ntation (W) (V) at (GHz) (GHz) frequency) 0.2 – 8

15

2.6 – 3

1–4

39

RLC Match

Distributed Amplifier

Ref.

Substrate [32]

0.2 GaN-SiC

0.05-12.3

15

1.5

3.5

0.001 – 3.4

28

5

3

0.05 – 2.2

28

8

0.05 – 2.0

32 – 56

Multichip module

0.05 – 2.2

48

20 (pulsed)

1–2

33 - 42

Multichip module

0.5-2.5

48

9-13.6

-

40-56

MMIC

[41]

0.02 – 2.0

28

10

0.02 – 2.0

30 – 70

Hybrid

[38]

0.1-2.2

28

8.7

-

30-66

MMIC

0.1-5

28

DC-24

30

0.02-6

50

21.4

Lg (um)

MMIC

(2 GHz)

Resistive Feedback

GaN HEMT Technology

23.5 (3 GHz)

2--3

1-3

23-30

4

0.1-2

25-30

>2

10

10-15

18.6-30.2

0.02-6

> 20

MMIC Hybrid

?

[14] [37]

[39]

0.5

0.5

• BW up to10 GHz • Po up to 4W • PAE ~ 20-40%

GaN-SiC

GaN-Si

MMIC

[39]

• • • •

BW up to 2.5 GHz Po up to13.6W 20W Pulsed PAE ~30-56%

• • •

BW ~ up to 6 (24) GHz Po up to 30 (4)W PAE ~20-70%

[40] [42]

MMIC

0.2

GaN-SiC

[43]

Packaged MMIC

0.4

GaN-SiC

[44]

MCM RLC Matched Approach ALN Package GaN DIE GaAs RLC Matching (b) Photograph

(a) Schematic

70

8W

P3dB (dBm)

40

60

39

50

38

40

P3dB

37

30

Drain Efficiency (%)

41

Drain Efficiency 36 0.0

0.5

1.0

1.5

20 2.0

Frequency (GHz)

(c) Measured P-3dB and Drain Efficiency

MCM RLC is a low cost approach which achieves 8W and wideband efficiency of 32-56%

Monolithic RLC Matched Vg

Vd

Bias Networks

Ld RF IN

Cdiv Zg Impedance transformation

Cd

RF OUT

Output match

RLC match

(b) Photograph

(a) Schematic 43

80

P3dB (dBm)

42

10W

Drain Efficiency

70

41

60

40

50

39

40

38 0.5

1.0

1.5

2.0

Drain Efficiency (%)

P3dB

30 2.5

Frequency (GHz)

(c) Measured P-3dB and Drain Efficiency

Monolithic RLC match achieves > 10W, improves BW by 25%, and upper BW efficiency by ~ 10%

GaN MMIC DA Approach

(a) Schematic

(b) Photograph

Psat, P1dB (dBm)

PAE ~ 25-30% Capacitively Coupled Cascode (Vdd=30V)

40 38 36 34 32 30 28 26 24 22 20

PAE ~10-15%

~ 4 Watts

Psat P1dB

Baseband

0

2

4

6

8

10

12

14

16

18

20

22

Frequency (GHz)

(a) Measured Psat & P1dB

DA approach offers higher Power-BW design trade space. There are several technique for improving DA power & linearity.

Linearized GaN MMIC DA Tapered Cascode Gate Periphery Linearizes NDPA (phase)

Non-uniform Distributed TLINs

All-pass Capacitive Coupled input

NDPA, Capacitive Coupled, Cascode approaches are popular for improving power capability of the DA.

Tapered Device Linearization Uniform vs. Tapered Device Cell Tapered - S11

30

Tapered - S21 Tapered - S22

20

Uniform -S11 Uniform - S21

Gain dBm

10

Uniform - S22

0 -10 -20 -30 0

5

10

15

20

25

Freq (GHz)

Device tapering has no impact on gain performance.

Tapered Device Linearization Uniform vs. Tapered Transistor Cell Periphery 46

Tapered Transistors

OIP3 (dBm)

44 42

Uniform Transistors

40 38 36 34 32 30 0

5

10

15

20

25

Frequency (GHz) Device tapering improves linearity-BW. As much as 3 dB improvement at 18 GHz.

Power

NTSC CATV Spectrum

256 QAM 55MHz

550MHz

1.002 GHz

CATV upgrades extend the BW beyond 1 GHz adding digital channels to support HDTV, VOD, & high speed internet creating the need for GaN Technology.

Typical CATV Distribution Distribution Network

Primary Hubs

Secondary Hubs

RF Amplifier Optical Node

Transport Network

CATV Line Amplifier

Line Amplifier Block Diagram

Return Path Output

Duplex Filter

Forward Path Input

Pre-Amplifier

Output Amplifier

Return Path Amplifier

Duplex Filter

GaN Power Doubler Hybrid

Forward Path Output

Return Path Input

GaN Power Doubler Amplifier

Replace GaAs with GaN

Block Diagram GaAs FET FET1

R R1

Port RFin

R R3

GaAs FET FET3

Port RFout

R R4 Port 24V

TF TF1

R R2 GaAs FET FET2

GaAs FET FET4

XFERTAP XFer1

GaN HEMTs enable higher linearity, efficiency, robustness for the output stage of the power doubler.

CATV CIN Linearity: GaN vs. GaAs 75

RFMD GaN

70

GaAs - 1

CIN (dB)

65

GaAs - 2

60 55

3.5 dB For CIN = 67 dB Output level increases 3.5 dB

50 45

RFMD GaN

GaAs -1

GaAs -2

equivalent to 13.5dB tilt and 56.5dBmVextrapolated to 1GHz

40

45

46

47

48

49 50 51 Output Level (dBmV)

52

53

54

GaN provides 3.5 dB higher linear Output Power vs. GaAs

55

GaN Device CATV Linearity Source

Gate

SiN Drain

Undoped AlGaN Undoped GaN S.I. SiC Substrate

CATV linearity is related to device Cdg linearity with Vds. Lower Al composition results in improved GaN CATV linearity.

Summary • RF Darlington Evolution • Linearization Techniques • Adv. Semiconductors Technology • Future • GaN E-mode for Power • 3.3V Infrastructure

• 100G Fiber Optics • • • •

Shift from serial OOK  higher order coherent modulation Linear TIAs High speed ADC’s Serial 100G? Niche short reach?

• Broadband (multi-octave) Linear GaN Applications • SDR • CATV (Digital & BW Extension)

Acknowledgment • RF Micro Devices • Tony Sellas, Curtis Kitani, Joe Johnson, Young Ryu, Brad Nelson, Terry Hon, Todd Fariss, Chuck Page, John Pelose, Günter Leicht, Conrad Young, Alastair Upton, M. Lefevre, B. Anderson, Jay Martin, Matthew Poulton, Saulius Smetona, Dave Aichele, Dave Runton, Norm Hilgendorf, Bob Van Buskirk and many others whose contributions are represented here.

• Northrop Grumman • For support of the GaN microwave MMIC DA linearization and LNA demonstrations described in this paper including the following contributors Richard To, Wen-Ben Luo, Ioulia Smorchkova, Benjamin Heying, William Sutton, YaoChung Chen, Mike Wojtowicz, Aaron Oki, Schaffer Grimm, Ed Rezek, and Frank Kropschot.

• Sirenza Microdevices • Finally thanks to John Ocampo, Greg Baker, Tim Gittemeier, Kin Tan and the original sirenza alumni for their contributions to the advancement of the commercial GaAs RF Darlington feedback amplifier.