Slide 1

Transistor and Circuit Transistor and Circuit Technologies for Technologies for Tomorrow’s Base Tomorrow’s Base

Station Power Station Power AmplifiersAmplifiers

Transistor and Circuit Transistor and Circuit Technologies for Technologies for Tomorrow’s Base Tomorrow’s Base

Station Power Station Power AmplifiersAmplifiers

Raymond S. PengellyRaymond S. Pengelly

Cree Microwave Cree Microwave

Durham, NC 27703 USADurham, NC 27703 USA

Raymond S. PengellyRaymond S. Pengelly

Cree Microwave Cree Microwave

Durham, NC 27703 USADurham, NC 27703 USA

2002 IEEE Topical Workshop onPower Amplifiers for Wireless Communications

Slide 2

More and More Power!More and More Power!More and More Power!More and More Power!• Assuming GSM as the reference with Assuming GSM as the reference with

0 dB Peak to Average Ratio to cover a 0 dB Peak to Average Ratio to cover a radius of X milesradius of X miles– EDGE requires 2 x power for same EDGE requires 2 x power for same

coveragecoverage– CDMA requires 4 x power for same CDMA requires 4 x power for same

coveragecoverage– W-CDMA requires 8 x power for same W-CDMA requires 8 x power for same

coveragecoverage– OFDM requires 15 x power for same OFDM requires 15 x power for same

coveragecoverage

• Assuming GSM as the reference with Assuming GSM as the reference with 0 dB Peak to Average Ratio to cover a 0 dB Peak to Average Ratio to cover a radius of X milesradius of X miles– EDGE requires 2 x power for same EDGE requires 2 x power for same

coveragecoverage– CDMA requires 4 x power for same CDMA requires 4 x power for same

coveragecoverage– W-CDMA requires 8 x power for same W-CDMA requires 8 x power for same

coveragecoverage– OFDM requires 15 x power for same OFDM requires 15 x power for same

coveragecoverage

Slide 3

““There are No Free Lunches”There are No Free Lunches”““There are No Free Lunches”There are No Free Lunches”

• More data per unit time requires more More data per unit time requires more bandwidth or clever modulation schemesbandwidth or clever modulation schemes

• Digital transmission techniques require Digital transmission techniques require more peak power for the same bit error more peak power for the same bit error rate for greater capacityrate for greater capacity

• In order to minimize spectral re-growth In order to minimize spectral re-growth and interference transmitters have to be and interference transmitters have to be more linearmore linear

• More data per unit time requires more More data per unit time requires more bandwidth or clever modulation schemesbandwidth or clever modulation schemes

• Digital transmission techniques require Digital transmission techniques require more peak power for the same bit error more peak power for the same bit error rate for greater capacityrate for greater capacity

• In order to minimize spectral re-growth In order to minimize spectral re-growth and interference transmitters have to be and interference transmitters have to be more linearmore linear

Slide 4

Competitive Power Transistor Competitive Power Transistor TechnologiesTechnologies

Competitive Power Transistor Competitive Power Transistor TechnologiesTechnologies

TECHNOLOGY Price/WattPOWERDENSITY

SUPPLYVOLTAGE

LINEARITY FREQ. PAE

Si BJT LOW COST MEDIUM 26 V POOR < 2 GHz LOW

SiGe BJT LOW COST MEDIUM < 20 V GOOD > 2 GHz HIGH

Si LDMOS LOW COST LOW 26 V V. GOOD < 3 GHz MEDIUM

GaAs MESFET COMPETITIVE MEDIUM 12 V GOOD > 2 GHz MEDIUM

GaAs PHEMT MEDIUM MEDIUM 8 V to 12 V V. GOOD > 2 GHz HIGH

GaAs HBT COMPETITIVE HIGH 8 V to 26 V GOOD > 2 GHz HIGH

SiC MESFET COMPETITIVE VERY HIGH 48 V GOOD > 4 GHz MEDIUM

GaN HEMT N/A VERY HIGH 48 V PROMISING > 12 GHz HIGH

Slide 5

• High Power DensityHigh Power Density– Reduced SizeReduced Size– Higher Working ImpedancesHigher Working Impedances– Simpler CircuitsSimpler Circuits– Easier ManufactureEasier Manufacture

• Wide Bandgap transistors on 4H-SiC and Wide Bandgap transistors on 4H-SiC and AlGaN/GaN provide superior performance to AlGaN/GaN provide superior performance to GaAs or Si counterpartsGaAs or Si counterparts– 4 to 6 Watts/mm for SiC MESFETs4 to 6 Watts/mm for SiC MESFETs– 10 to 12 Watts/mm for AlGaN/GaN HFETs10 to 12 Watts/mm for AlGaN/GaN HFETs

• High Power DensityHigh Power Density– Reduced SizeReduced Size– Higher Working ImpedancesHigher Working Impedances– Simpler CircuitsSimpler Circuits– Easier ManufactureEasier Manufacture

• Wide Bandgap transistors on 4H-SiC and Wide Bandgap transistors on 4H-SiC and AlGaN/GaN provide superior performance to AlGaN/GaN provide superior performance to GaAs or Si counterpartsGaAs or Si counterparts– 4 to 6 Watts/mm for SiC MESFETs4 to 6 Watts/mm for SiC MESFETs– 10 to 12 Watts/mm for AlGaN/GaN HFETs10 to 12 Watts/mm for AlGaN/GaN HFETs

New DevicesNew DevicesNew DevicesNew Devices

More inherent DC to RF Efficiency and Linearity are Key

Slide 6

Envelope Distribution FunctionsEnvelope Distribution FunctionsEnvelope Distribution FunctionsEnvelope Distribution Functions• Power capability is a direct function of where a Power capability is a direct function of where a

power amplifier starts to saturatepower amplifier starts to saturate• Average spectral re-growth is a function ofAverage spectral re-growth is a function of

– Power capabilityPower capability

– Envelope statisticsEnvelope statistics

– Clipping, even for short periods of time, is a serious Clipping, even for short periods of time, is a serious issueissue

• Power capability is a direct function of where a Power capability is a direct function of where a power amplifier starts to saturatepower amplifier starts to saturate

• Average spectral re-growth is a function ofAverage spectral re-growth is a function of– Power capabilityPower capability

– Envelope statisticsEnvelope statistics

– Clipping, even for short periods of time, is a serious Clipping, even for short periods of time, is a serious issueissue

                                                                                                               

Slide 7

• Peak to Average Ratio is 15 dB

Slide 8

W-CDMAW-CDMAW-CDMAW-CDMA• For the majority of the time (> 90%) the For the majority of the time (> 90%) the

basestation transmitter delivers power at 1/8 basestation transmitter delivers power at 1/8 its peak power capability (but it needs to be its peak power capability (but it needs to be able to deliver able to deliver anyany power level up to the power level up to the peak)peak)

• At peak power the overall base-station is At peak power the overall base-station is typically 20% efficient but for most of the typically 20% efficient but for most of the time it is only 6% efficient since the PA’s time it is only 6% efficient since the PA’s become less efficient when backed-offbecome less efficient when backed-off

2.35 Kilowatts in for 140 watts out!2.35 Kilowatts in for 140 watts out!

• For the majority of the time (> 90%) the For the majority of the time (> 90%) the basestation transmitter delivers power at 1/8 basestation transmitter delivers power at 1/8 its peak power capability (but it needs to be its peak power capability (but it needs to be able to deliver able to deliver anyany power level up to the power level up to the peak)peak)

• At peak power the overall base-station is At peak power the overall base-station is typically 20% efficient but for most of the typically 20% efficient but for most of the time it is only 6% efficient since the PA’s time it is only 6% efficient since the PA’s become less efficient when backed-offbecome less efficient when backed-off

2.35 Kilowatts in for 140 watts out!2.35 Kilowatts in for 140 watts out!

Slide 9

Typical Amplifier Line-upTypical Amplifier Line-upTypical Amplifier Line-upTypical Amplifier Line-up

10 30 125

750 watt peak amplifiercontains 30 LDMOSFETs@ a total price of$3,000

Numbers are Peak Watts

Slide 10

Wide-Band Power ModulesWide-Band Power ModulesWide-Band Power ModulesWide-Band Power Modules

Slide 11

Typical Basestation Power AmplifierTypical Basestation Power AmplifierTypical Basestation Power AmplifierTypical Basestation Power Amplifier• OLD - Lots of Silicon Power (400 watts)! - But physically LARGE• Power Density of < 10 watts per sq. inch

• NEW LDMOSPower FET Modulesincrease Power Density to25 to 100 Wattsper sq. inch

Slide 12

The Need for Smaller PA’sThe Need for Smaller PA’sThe Need for Smaller PA’sThe Need for Smaller PA’s

Power Amplifiers with Fans

Macrocell Basestation Hut- “Lots” of Space!

• Going to Microcell• Higher powers in the same space• Tower Top Arrays with no fans

Slide 13

…….The Difference between an LDMOS .The Difference between an LDMOS Transistor and a Silicon Carbide MESFET Transistor and a Silicon Carbide MESFET

for 30 Watts Output Powerfor 30 Watts Output Power

LD-MOSFETLD-MOSFET SiC MESFET SiC MESFET

Slide 14

• GaN based amplifier: 6 W out to 50 GaN based amplifier: 6 W out to 50 • GaAs based amplifier: 0.6 W out to 50 GaAs based amplifier: 0.6 W out to 50 -without impedance transformation-without impedance transformation

Device InputCapacitance

I max

mA/mmVmax

(V)ft /fmax

GHzLoadimpedanceOhms

Power(W)

GaAsp-HEMT 3 pF 600 20 30/90 33 ~ 1

GaNHEMT

3 pF 1200 60 30/90 50 ~ 6

GaN Amplifier- Comparison to GaAs pHEMTGaN Amplifier- Comparison to GaAs pHEMT

- 10x less impedance transformation- 10x less impedance transformation

- 5-10 x - 5-10 x Higher BandwidthHigher Bandwidth

- Simpler, Smaller circuits, High Yield, Low cost- Simpler, Smaller circuits, High Yield, Low cost

Slide 15

Key figure of merit is how much power the device Key figure of merit is how much power the device can handle in terms of W/mmcan handle in terms of W/mm22 of die area of die area

• Die size is constrained by wavelengthDie size is constrained by wavelength

- Y-dimension is limited by gate - Y-dimension is limited by gate RR and and LL

- X-dimension is limited by phasing issues- X-dimension is limited by phasing issues

Gate Width Power Transistor

/4

Thermal Conductivity is Critical for Thermal Conductivity is Critical for High PowerHigh Power

Slide 16

• SiC has a very high thermal conductivity of 4.9 W/cm-KSiC has a very high thermal conductivity of 4.9 W/cm-K--GaAs: 0.4, Si: 1.5, Sapphire: 0.4GaAs: 0.4, Si: 1.5, Sapphire: 0.4

GaN on SiC: The Thermal AdvantageGaN on SiC: The Thermal Advantage

SiC delivers higher power from given chip area => SiC delivers higher power from given chip area => SiC SiC has higher W/mmhas higher W/mm22 => reduces $/W => reduces $/W

Gate pitch with Silicon

Gate pitch with SiC

Gate pitch with SiliconGate pitch with SiC

Slide 17

3” SiC Vs. 4” Si Wafer3” SiC Vs. 4” Si Wafer

3-inch SiC 4-inch SiTotal die 860 532Non-edge die 788 484

• 100 W GaN HEMTs: Die size on 100 W GaN HEMTs: Die size on SiC: 1 x 4 mmSiC: 1 x 4 mm22, Die size on , Die size on Si: 2 x 6 mmSi: 2 x 6 mm22 • Fabrication (not Substrate) is the more expensive cost componentFabrication (not Substrate) is the more expensive cost component

3” SiC3” SiC 4” Si4” Si

Slide 18

High Power Density & PAE from SiC MESFETsHigh Power Density & PAE from SiC MESFETsHigh Power Density & PAE from SiC MESFETsHigh Power Density & PAE from SiC MESFETs

• Pulsed on-wafer power densities of 5-6 W/mm consistently achieved Pulsed on-wafer power densities of 5-6 W/mm consistently achieved on large FETson large FETs

• Pulsed on-wafer power densities of 5-6 W/mm consistently achieved Pulsed on-wafer power densities of 5-6 W/mm consistently achieved on large FETson large FETs

10 15 20 25 30 35 4025

30

35

40

45

50

WG = 8 mm

Freq. = 3 GHz

VDS

= 60 V

P3dB

= 48 W (6 W/mm)

PAE = 45%

Gain = 10 dB

Input Power (dBm)O

utpu

t Pow

er (

dBm

)

0

10

20

30

40

50

PA

E (%

)

12 14 16 18 20 2224

26

28

30

32

34

0.25-mm SiC MESFETFreq. = 3.5 GHzVDS = 50 V, VGS = -8 V

P2dB

= 5.2 W/mmG

Assoc = 11.1 dB

PAE = 63%

Input Power (dBm)

Out

put P

ower

(dBm

)

0

10

20

30

40

50

60

70

Gain

POUT

PAE

PAE (%) or G

ain (dB)

Slide 19

SiC MESFET with 7.2 W/mmSiC MESFET with 7.2 W/mmSiC MESFET with 7.2 W/mmSiC MESFET with 7.2 W/mm

• Power density of 7.2 W/mm with 45% PAE at S-band demonstrates Power density of 7.2 W/mm with 45% PAE at S-band demonstrates the capability of the technologythe capability of the technology

• Power density of 7.2 W/mm with 45% PAE at S-band demonstrates Power density of 7.2 W/mm with 45% PAE at S-band demonstrates the capability of the technologythe capability of the technology

0.00 0.05 0.10 0.15 0.200.0

1.0

2.0

3.0

4.0

5.0

6.0

7.0

8.0

W G = 0.25 mm

Freq. = 3 GHz

VDS = 70 V

Power Density = 7.2 W/mm

Efficiency = 48%P

ow

er

De

nsi

ty (

W/m

m)

Input Power (W)

Slide 20

Mobile Telephone Frequency AllocationsMobile Telephone Frequency AllocationsMobile Telephone Frequency AllocationsMobile Telephone Frequency Allocations

Slide 21

20-Watt Broadband SiC MESFET Amplifier20-Watt Broadband SiC MESFET Amplifier20-Watt Broadband SiC MESFET Amplifier20-Watt Broadband SiC MESFET Amplifier

• 22 W at P22 W at P1dB1dB across a 400 MHz band across a 400 MHz band

• Advantage of wide bandgap transistors: power-bandwidth product Advantage of wide bandgap transistors: power-bandwidth product greatly exceeding Si LDMOSgreatly exceeding Si LDMOS

• 22 W at P22 W at P1dB1dB across a 400 MHz band across a 400 MHz band

• Advantage of wide bandgap transistors: power-bandwidth product Advantage of wide bandgap transistors: power-bandwidth product greatly exceeding Si LDMOSgreatly exceeding Si LDMOS

Balanced Amplifier with 10-Watt, CRF22010 FETsBalanced Amplifier with 10-Watt, CRF22010 FETs

2

4

6

8

10

12

14

16

1.7 1.8 1.9 2.0 2.1 2.2 2.3 2.4

Frequency (GHz)G

ain

(dB)

30

32

34

36

38

40

42

44

P1dB

(dBm

)

GainP1dBmW-CDMA

3GPP Test Model 1 with 16 DPCH

Slide 22

75-Watt SiC MESFET Amplifier75-Watt SiC MESFET Amplifier75-Watt SiC MESFET Amplifier75-Watt SiC MESFET Amplifier

• 75 W CW, 11 dB gain demonstrated from a single SiC MESFET75 W CW, 11 dB gain demonstrated from a single SiC MESFET

• Currently 60-Watt Class A/B MESFET transistor being Currently 60-Watt Class A/B MESFET transistor being optimized, targeted for production release by the end of 2002optimized, targeted for production release by the end of 2002

• REAL POWER!REAL POWER!

• 75 W CW, 11 dB gain demonstrated from a single SiC MESFET75 W CW, 11 dB gain demonstrated from a single SiC MESFET

• Currently 60-Watt Class A/B MESFET transistor being Currently 60-Watt Class A/B MESFET transistor being optimized, targeted for production release by the end of 2002optimized, targeted for production release by the end of 2002

• REAL POWER!REAL POWER!

28 30 32 34 36 38 4040

42

44

46

48

50

Freq. = 2.0 GHz

Power

Input Power (dBm)

Ou

tpu

t P

ow

er

(dB

m)

0

10

20

30

40

50

PAE

PA

E (%

)

2 GHz test fixture for 60 W 2 GHz test fixture for 60 W MESFET developmentMESFET development

Slide 23

Broadband SiC MESFET AmplifierBroadband SiC MESFET Amplifier200 MHz to 2200 MHz200 MHz to 2200 MHz

In Out

Gate Bias

Drain Bias

0.6 0.6 2.4 1.1 0.5

100 190 ohms

All capacitor values in pF

Slide 24

Ultra Broadband AmplifiersUltra Broadband AmplifiersUltra Broadband AmplifiersUltra Broadband Amplifiers

• Broadband for Multi-Frequency and Multi-ModeBroadband for Multi-Frequency and Multi-Mode• Broadband for Multi-Frequency and Multi-ModeBroadband for Multi-Frequency and Multi-Mode

Slide 25

GaN HEMTs for Power AmplifiersGaN HEMTs for Power Amplifiers Enabling FeatureEnabling Feature Performance AdvantagePerformance Advantage

High Power/Unit Width- Higher High Power/Unit Width- Higher Watts/pF(10 x GaAs)Watts/pF(10 x GaAs)

Smaller die size per Watt of output powerSmaller die size per Watt of output powerEase of matching, HIGHER BANDWIDTHEase of matching, HIGHER BANDWIDTH

High EfficiencyHigh Efficiency(> 60%)(> 60%)

Power saving, reduced coolingPower saving, reduced cooling

High Voltage OperationHigh Voltage Operation(3-5 x GaAs, 1.5-2 x LDMOS)(3-5 x GaAs, 1.5-2 x LDMOS)

Eliminate / reduce step downEliminate / reduce step downCapable of 10-50 Volt operationCapable of 10-50 Volt operation

High Cutoff FrequenciesHigh Cutoff Frequencies(GaAs like, 15 GHz-(GaAs like, 15 GHz-m fm f--

LLgg))

High gain, high efficiency operationHigh gain, high efficiency operation

Superior Thermal ConductivitySuperior Thermal ConductivityFor GaN on SiCFor GaN on SiC

Higher junction temperature, smaller pitch+ Higher junction temperature, smaller pitch+ higher device density, ease of packaginghigher device density, ease of packaging

Slide 26

GaN HEMT with 12 W/mmGaN HEMT with 12 W/mmGaN HEMT with 12 W/mmGaN HEMT with 12 W/mm

• Peak pulsed power density of 12 W/mm on a 0.5-mm HEMTPeak pulsed power density of 12 W/mm on a 0.5-mm HEMT• CW power from same device of 9 W/mmCW power from same device of 9 W/mm

• Peak pulsed power density of 12 W/mm on a 0.5-mm HEMTPeak pulsed power density of 12 W/mm on a 0.5-mm HEMT• CW power from same device of 9 W/mmCW power from same device of 9 W/mm

10 12 14 16 18 20 22 24 26 2826

28

30

32

34

36

38

40

42

3.5 GHzV

ds = 90V

Vgs

= -2.4V10 s Pulses, 0.1% Duty Cycle

Pout Gain

Input Power (dBm)

Ou

tpu

t P

ow

er

(dB

m)

0

2

4

6

8

10

12

14

16

18

20

22

24

26

28

30

32

34

36

12.1 W/mm

Ga

in (d

Bm

)

Slide 27

0

5

10

15

20

25

30

35

40

45

50

10 15 20 25 30 35200

300

400

500

600

700

800Pout

Gain

PAE

Id

Pin (dBm)P

out (

dBm

), G

ain(

dB),

PA

E(%

)

I d (m

A)

Vds = 30 V

-1.1 dB compressionPout = 12.5 WPAE = 46 %

f = 4 GHz

Packaged GaN HEMTs Packaged GaN HEMTs

P1dB of 12 W, 46% PAE at 4 GHz at 30 Volts

Slide 28

0

10

20

30

40

50

60

70

5 15 25 35 45

Vdd (V)D

E(%

)

Drain efficiency at 3dB gain compression vs. supply voltage

0

1

2

3

4

5

6

7

8

9

10

-5 0 5 10 15 20 25

-30

-20

-10

0

10

20

30

40

50

60

70

Power sweep

Vdd (V): 10, 15, 20, 25, 30, 35, 40

W=300m

Characterization of AlGaN/GaN HEMTs Characterization of AlGaN/GaN HEMTs Using Fixed Load at Varying Voltage SupplyUsing Fixed Load at Varying Voltage Supply

Slide 29

Cellular Base-Station ApplicationCellular Base-Station ApplicationCellular Base-Station ApplicationCellular Base-Station Application

Slide 30

10-Watt Broadband GaN HEMT Amplifier10-Watt Broadband GaN HEMT Amplifier10-Watt Broadband GaN HEMT Amplifier10-Watt Broadband GaN HEMT Amplifier

• 11 W at P11 W at P1dB1dB across the 400 MHz to 2200 MHz band across the 400 MHz to 2200 MHz band

• 17 dB gain with only ±0.5 dB ripple17 dB gain with only ±0.5 dB ripple• Great for a generic driver amplifierGreat for a generic driver amplifier

• 11 W at P11 W at P1dB1dB across the 400 MHz to 2200 MHz band across the 400 MHz to 2200 MHz band

• 17 dB gain with only ±0.5 dB ripple17 dB gain with only ±0.5 dB ripple• Great for a generic driver amplifierGreat for a generic driver amplifier

30

32

34

36

38

40

42

44

1.5 1.6 1.7 1.8 1.9 2 2.1 2.2 2.3 2.4

Frequency (GHz)P

1dB

(dB

m)

10

12

14

16

18

20

22

24

Sm

all Signal G

ain (dB)

P1dB (dbm)

SS Gain (dB)

Slide 31

GaN HEMTs for Infrastructure:GaN HEMTs for Infrastructure:2 GHz, CW Power from a 24-mm HEMT2 GHz, CW Power from a 24-mm HEMT

Record Power exceeding 100 WattsRecord Power exceeding 100 Watts

32 34 36 38 40 42 44

44

46

48

50

Input Power (dBm)

Out

put

Pow

er (

dBm

)0

5

10

15

20

25

30

35

40

Gain(dB

)

f = 2 GHz, Vds = 52 V

• 103 W at 2.6 dB gain compression103 W at 2.6 dB gain compression• Peak Drain Efficiency of 54 % Peak Drain Efficiency of 54 %

Peak Power= 108 W CWPower Density = 4.5 W/mm

Slide 32

High Temperature OperationHigh Temperature OperationHigh Temperature OperationHigh Temperature Operation

• Demonstrated that at a TDemonstrated that at a TJJ of 180 of 180OOC C

(case temperature of 120(case temperature of 120OOC) SiC C) SiC MESFET has a mission life of > 20 years MESFET has a mission life of > 20 years (3 (3 confidence level) confidence level)– Equivalent maximum junction temperature Equivalent maximum junction temperature

for Si LDMOS is 130 for Si LDMOS is 130 OOCC– Equivalent maximum junction temperature Equivalent maximum junction temperature

for GaAs MESFET is 110 for GaAs MESFET is 110 OOCC

• Demonstrated that at a TDemonstrated that at a TJJ of 180 of 180OOC C

(case temperature of 120(case temperature of 120OOC) SiC C) SiC MESFET has a mission life of > 20 years MESFET has a mission life of > 20 years (3 (3 confidence level) confidence level)– Equivalent maximum junction temperature Equivalent maximum junction temperature

for Si LDMOS is 130 for Si LDMOS is 130 OOCC– Equivalent maximum junction temperature Equivalent maximum junction temperature

for GaAs MESFET is 110 for GaAs MESFET is 110 OOCC

Slide 33

So, what does this mean for next So, what does this mean for next generation infrastructure generation infrastructure

power amplifiers?power amplifiers?

So, what does this mean for next So, what does this mean for next generation infrastructure generation infrastructure

power amplifiers?power amplifiers?• Easier and more tolerant designsEasier and more tolerant designs

• Higher operating temperaturesHigher operating temperatures

• Removal of DC-DC converters (voltage Removal of DC-DC converters (voltage versus current)versus current)

• RuggednessRuggedness

• Wider Band DesignsWider Band Designs

• Smaller UnitsSmaller Units

• Easier and more tolerant designsEasier and more tolerant designs

• Higher operating temperaturesHigher operating temperatures

• Removal of DC-DC converters (voltage Removal of DC-DC converters (voltage versus current)versus current)

• RuggednessRuggedness

• Wider Band DesignsWider Band Designs

• Smaller UnitsSmaller Units

Slide 34

Wide Bandgap is an Enabling TechnologyWide Bandgap is an Enabling TechnologyWide Bandgap is an Enabling TechnologyWide Bandgap is an Enabling Technology

• Wide Bandgap can provide a paradigm shift in Wide Bandgap can provide a paradigm shift in the 4G infrastructure sector:the 4G infrastructure sector:

– Allows Tower Top Installations – lowers power Allows Tower Top Installations – lowers power requirements by at least a factor of 2 by requirements by at least a factor of 2 by eliminating cable losseseliminating cable losses

– Fan-less Operation will be possible – enabled Fan-less Operation will be possible – enabled by higher transistor operating temperaturesby higher transistor operating temperatures

– Will make cost-effective Smart Antennas Will make cost-effective Smart Antennas viableviable

– Integration of SiC with other technologies in Integration of SiC with other technologies in standard “Lego” modules – economies of standard “Lego” modules – economies of scale scale

• Wide Bandgap can provide a paradigm shift in Wide Bandgap can provide a paradigm shift in the 4G infrastructure sector:the 4G infrastructure sector:

– Allows Tower Top Installations – lowers power Allows Tower Top Installations – lowers power requirements by at least a factor of 2 by requirements by at least a factor of 2 by eliminating cable losseseliminating cable losses

– Fan-less Operation will be possible – enabled Fan-less Operation will be possible – enabled by higher transistor operating temperaturesby higher transistor operating temperatures

– Will make cost-effective Smart Antennas Will make cost-effective Smart Antennas viableviable

– Integration of SiC with other technologies in Integration of SiC with other technologies in standard “Lego” modules – economies of standard “Lego” modules – economies of scale scale

Slide 35

Conventional New Approach Conventional New Approach

3dB Loss 3dB Loss in Cablein Cable

AntennaAntenna½ X watts½ X watts

PowerPowerAmplifiers @Amplifiers @28 volts28 volts (X watts)(X watts)

Antenna withAntenna withPower amplifiersPower amplifiers@ 48 volts@ 48 volts½ X watts½ X watts

Wide Bandgap enables Wide Bandgap enables Tower-Top Power AmplifiersTower-Top Power Amplifiers

EfficiencyEfficiency= 50% x= 50% x85% x 30%85% x 30%= 12%= 12%If you’re If you’re really really lucky!lucky!

EfficiencyEfficiency= 30%= 30%

Slide 36

Summary of Features of Wide Bandgap Summary of Features of Wide Bandgap TransistorsTransistors

Summary of Features of Wide Bandgap Summary of Features of Wide Bandgap TransistorsTransistors

• High Power density and high operating voltageHigh Power density and high operating voltage• More convenient impedance levels than Si LDMOS or More convenient impedance levels than Si LDMOS or

GaAs FETGaAs FET– easier and more tolerant designeasier and more tolerant design– broadband amplifiersbroadband amplifiers

• High Temperature OperationHigh Temperature Operation• High Voltage Operation High Voltage Operation

– allows drain modulation techniques (28 volts avg. allows drain modulation techniques (28 volts avg. 48 volts peak) for increased efficiency48 volts peak) for increased efficiency

• RuggedRugged

• High Power density and high operating voltageHigh Power density and high operating voltage• More convenient impedance levels than Si LDMOS or More convenient impedance levels than Si LDMOS or

GaAs FETGaAs FET– easier and more tolerant designeasier and more tolerant design– broadband amplifiersbroadband amplifiers

• High Temperature OperationHigh Temperature Operation• High Voltage Operation High Voltage Operation

– allows drain modulation techniques (28 volts avg. allows drain modulation techniques (28 volts avg. 48 volts peak) for increased efficiency48 volts peak) for increased efficiency

• RuggedRugged

Slide 37

Next Steps?Next Steps?Next Steps?Next Steps?

• ProductizationProductization• Customer “Education”Customer “Education”• Reliability FactsReliability Facts• Acceptable Dollars/WattAcceptable Dollars/Watt• Introduction of RFICsIntroduction of RFICs• Nothing we haven’t been Nothing we haven’t been

through with other technologies through with other technologies

– WATCH THIS SPACE!WATCH THIS SPACE!

• ProductizationProductization• Customer “Education”Customer “Education”• Reliability FactsReliability Facts• Acceptable Dollars/WattAcceptable Dollars/Watt• Introduction of RFICsIntroduction of RFICs• Nothing we haven’t been Nothing we haven’t been

through with other technologies through with other technologies

– WATCH THIS SPACE!WATCH THIS SPACE!