Presentation, Click to open in new window

Defining Application Spaces
for High Power GaN
David Runton, Dave Aichele, Michael LeFevre, Christopher Burns
RFMD, Chandler, AZ
Summary
• Exploring the options for GaN
• Value Proposition
• Market Segments
• Product alignment
• Timing is NOW! Data is REAL!
• Enabling Wide Bandwidth
• Enabling Very High Power
• Enabling Future Infrastructure
• Enabling High Efficiency
• Conclusions
GaN Value Proposition
End User Benefits
GaN-on-SiC
S
G
D
GaN
SiC
High Breakdown Voltage
High Power Density
Energy
Efficient
CAPEX
Reduce cost:
(i) air conditioning
(ii) site acquisition
(iii) battery
OPEX
Reduce cost:
(i) maintenance
(ii) electricity
(iii) battery
Incr. reliability
OEM Benefits
Reliable &
Compact HPAs
Reduced Capacitance
High Efficiency Circuit Techniques
Lower Heat Dissipation
Increase Efficiency
High Impedance
Multi-band Operation
Configurable Radio
Increase Bandwidth
Reduced: (1) size/complexity
(2) cooling
(3) weight and
(4) cost
GaN: Multiple Efficiency Benefits
Linearity & Bandwidth
Green
Improved performance
More power efficient
Especially for LTE/WiMAX
Per mW of RF power
Scale
Build GaN in existing GaAs fabs
Marginal cost delta
ε
Power & Size
More RF power per mm2
Opex/Capex
BOM & Running costs reduced
Reduced total cost of ownership
48V, 120W GaN
3.5mm2
Equivalent LDMOS Die
is ~5X the size
GaN vs. LDMOS
440MHz 180W PA Module
90w GaN die
90w LDMOS die
2 per module
Efficiency
Gain
Operating Voltage
84%
26dB
48V
2 per module
Efficiency
Gain
Operating Voltage
74%
22dB
28V
Product Alignment
Military Communications & Radar Market
Military Market Drivers
• Radar
– provide larger detection area
– improve early detection
– reduce size & weight
• Military Communications
S-Band Phase Array Radar
JTRS Handheld Radio
– improve battery life
– multi-standards for inter-operability
– wide-band architecture for portable
and mobile platforms
– Volume COTS model
Why GaN
• Higher Efficiency
– reduce heat sink requirements, smaller size
– increase battery life
• Wide bandwidth
– replace (3 to 5) amplifiers with (1) amplifier
– improve engineering efficiency
• Higher Power Density & Operating Voltage
– increase power with same form factor
Product Alignment
Cellular Infrastructure Market
BTS Market Drivers
• Remote Radio Heads
– eliminate 3dB cable loss
– reduce size & cooling
demands
• Improve BTS efficiency
Cellular Base Station (BTS)
RF Power Amplifier
Why GaN
• Higher Efficiency with latest PA Architectures
– reduce heat sink requirements, smaller size
– reduce operation expenses / electricity costs
• Wide bandwidth & linearity
– reduce amplifier inventory
– improve engineering efficiency
– reduce CapEx & OpEx costs
– utilize renewable energy
sources
• Wideband Platforms
– reduce inventory
– configurable systems support
multi-standards
Product Alignment
RFMD Product Categories
Matched Power Transistors (MPT)
High power amplifier; 48V-65V, 200-500W Pulsed;
optimized for high power/efficiency, Input/Output matched
25 to 50Ω interface
Value
RFG1M Series BTS Discrete Devices
High power amplifier; 48V 30 to 360W CW; optimized for
linear applications, Input matched no output match
Wide-Band Power IC (PIC)
High power ‘gain block’; 28V to 48V, 10 to 30W CW;
optimized wide bandwidth constant gain, 50Ω input
matched
Unmatched Power Transistor (UPT)
High power amplifier; 10-120 watts CW; No input or output
match, tunable bandwidth and high peak power/efficiency
RFMD GaN-RF Product Details
POWER TRANSISTOR
SPECIFICATIONS
• Voltage: up to 48V
• Operating Frequency: DC-7GHz
• Output Power: 10 – 120W
• Power Gain: 14dB
• Drain Efficiency: >50%
ATTRIBUTES
• Wide Bandwidth
• Tunable Bandwidth
WIDEBAND POWER-IC
SPECIFICATIONS
• Voltage: 28V
• Operating Frequency:
PMR, WCDMA, WiMAX
• Output power: < 12 W
• Power Gain: 11-14dB
• Drain Efficiency: 50% to 75%
ATTRIBUTES
• Wide bandwidth
• 50Ω input impedance
GaN die
GaAs die
INTERNALLY MATCHED FET
SPECIFICATIONS
• Voltage: up to 65V
• Operating Frequency:
from 800 – 3.5GHz
• Output Power: 30 – 500W
• Power Gain = 16dB
• Drain Efficiency: >65%
ATTRIBUTES
• Optimized for High efficiency
• Higher impedances
GaN die
GaN die
GaAs
die
Impedance matching
GaN Unmatched Power Transistors
•
Applications:
–
–
–
–
–
•
General purpose broadband amplifiers
Civilian/Military radars
EW Jammers
MILCOM/Public mobile radio
Wireless Infrastructure
Features/Benefits:
–
–
–
–
–
High Power Density > 5W/mm
48V bias operation
30-120W products available
High terminal impedance – tunable wide BW
Peak Drain Efficiency ~65% @ 2.1GHz
GaN Performance Characterization
2.1GHz 3 temperature characterization
Gain variation over temp: 0.011dB/C
Three different lots
GaN Enables Wider Bandwidth
CHALLENGE: Multiple amplifiers needed to cover cellular/WiMAX bands
SOLUTION: GaN enables multiple bands covered with a single amplifier
60W GaN WCDMA
8W GaN WiMAX
WiMAX 2.5GHz Band
WiMAX 3.5GHz Band
10
S11 (dB)
S21 (dB)
S22 (dB)
S12 (dB)
0
LDMOS
5
LDMOS
Gain (dB) Return Loss (dB)
Gain (dB) Return Loss (dB)
15
-5
-10
-15
-20
-25
-30
2.0
frequency (GHz)
2.2
2.4
2.6
2.8
3.0
3.2
3.4
3.6
frequency (GHz)
LDMOS
LDMOS
3.8
4.0
GaN Broadband Power IC
30
Applications:
– General purpose amplifiers
– Public Mobile Radios
– Military Communications
– EW Jammers
25
Power (W)
•
Product C
20
15
Product A
10
Product B
5
0
0
•
Features:
– 28V and 48V, multiple power levels
– Small Form Factor, 5mmx6mm
Package
– Broadband power/gain performance
– 50ohm Input impedance match
– 1dB gain flatness across bandwidth
0.5
1.0
1.5
2.0
Frequency (GHz)
13
2.5
GaN Broadband Power IC
28V 50MHz to 1.0GHz 15W Amplifier
Output power and PAE over frequency
Output Power, PAE and Gain at 500 MHz
70
40
42
60
41
50
P3dB
40
40
PAE
39
30
0.0
0.2
0.4
0.6
Frequency (GHz)
0.8
1.0
70
Output Power
PAE
Gain
35
60
50
30
40
25
30
20
20
15
10
10
0
5
10
15
20
Pin (dBm )
25
30
35
PAE (%), Gain (dB)
43
Output Power (dBm)
45
PAE (%)
80
P3dB (dBm)
44
GaN Broadband Power IC
28V 30MHz to 2.2GHz 10W Amplifier
Output Power, PAE and Gain at 2200 MHz
40
41
60
35
40
50
39
40
Psat
38
30
PAE
37
0.0
0.5
1.0
20
1.5
Frequency (GHz)
2.0
2.5
50
Output Power
PAE
Gain
40
30
30
25
20
20
10
15
0
5
10
15
20
Pin (dBm )
25
30
35
PAE (%), Gain (dB)
70
Output Power (dBm)
42
PAE (%)
Psat (dBm)
Output power and PAE over frequency
GaN Enables Very High Power
•
Applications:
– General purpose amplifiers
– Air Traffic Control
– Military Radar
– S-Band Radar
•
Features:
– 48V, 300W Pulse (100us PW,10%
DC)
– Small form factor 24mmx17.4mm
– Broadband power/gain performance
– 35ohm I/O impedance match
16
GaN Matched High Power Transistor
48V 2.5GHz to 3.5GHz 300W
17
GaN Enables Infrastructure
•
•
Applications:
– Wireless Infrastructure Amplifiers
Features:
– 48V operation
– Input Matched for broadband operation
– Easily linearizable using standard DPD algorithms.
GaN Enables Software Defined Radio
Single tuning performance 2.25-2.7GHz
Pout = 45.25dBm, Gain > 13.25dB, Drain Efficiency > 25.5%
3GPP TM1 – 7.5dB PAR @ 0.01% CCDF
GaN Enables Higher Efficiency
System Complexity
GaN dominates - superior
material & device properties
switch
mode
EER
wideband
DPD
ET
DM
LEGEND:
DPD
Doherty
Deployed
feed
forward
unlinearized
In development
ET-envelope tracking
DM-drain modulation
DPD-digital pre-distortion
EER-envelope elimination
& recovery
LDMOS offers mature
technology, adequate linearity
time
Increasingly important for linear modulation schemes LTE, WiMAX and future standards
GaN Enables High Efficiency - Doherty
• Performance
• 865-890MHz optimized
• 855-910MHz 0.25dB gain flatness
• Pout = 50 dBm
• Efficiency > 49%
• Gain > 17.7dB
• ACP (DPD) < -52dBc
• Circuit Area Size
• 114 x 80 mm
• PCB assembled on standard
127 x 127mm reference circuit
20
0
18
-3
Gain (dB)
14
PAR (dB)
12
IRL (dB)
-6
-9
-12
10
-15
8
-18
6
-21
4
-24
52
-15
50
-20
48
-25
46
-30
44
-35
42
-40
40
-45
38
-50
36
800
820
840
860
880
900
Frequency (MHz)
920
940
-55
960
IRL (dB)
16
ACP @ 5 MHz (dBc), ALT
@ 10 MHz (dBc)
Drain Efficiency (%)
Gain (dB), PAR (dB)
Broadband Doherty Performance
WCDMA (3GPP 7.5 dB PAR @0.01% CCDF)
Avg Pout = 50 dBm
Vdd = 48V
Main Idq = 650 mA
Peaking Vg = -6.5V
NO DPD correction
Eff (%)
ACP +/- 5 MHz (dBc)
ALT +/- 10 MHz (dBc)
D rain Efficien cy (% )
Broadband Doherty Performance
CW Power Sweep at 882.5MHz
70
65
60
55
50
45
40
35
30
25
20
2x Class AB
Vgpk = -8.0V
Vgpk = -7.5V
Vgpk = -7.0V
Vgpk = -6.5V
Vgpk = -6.0V
Vgpk = -5.5V
Vgpk = -5.0V
42
43
44
45
46
47
48
49
50
Pout (dBm)
Vdd= 48V, Main Idq = 650 mA
51
52
53
54
55
56
57
GaN Enables High Efficiency
Drain Modulation
• Use static characterization overlaying statistics of the drive signal
• Find “average” operating condition to determine optimum tuning point
• Mapped Data to 1 Car, WCDMA TM1, 7.5 dB PAR
• 15V – 55 V, 15 dBm – 39 dBm
Mapped Performance (PAE, Pout)
7
6
45
46.5
46
Imag Impedances ()
Max PAE @ 4.00 + j*4.60 Ohms
Avg PAE = 68.19%
Avg Pwr = 47.30 dBm
45
45.5
42
43
44
5
68
47
47.5
4
66
3
62
Original Impedance
Z = 8.0 + j3.6
64
54
56 58
2
58
Meas Imp
Mapped PAE
Mapped Pout
Fixture
Opt Tune
60
58
1
0
2
3
4
5
6
7
8
Optimized Impedance
Z = 4.00 + j4.60
9
Real Impedances ()
*See Asbeck P.et al., “Augmented Behavioral Characterization for Modeling the Nonlinear Response of Power Amplifiers”,IEEE MTT-S Digest 2002
GaN PAE Performance vs. Vdd
PAE vs VDD
75
Using different criteria to
optimize PAE can improve
performance
70
65
PAE (%)
60
P2dB follows closely to
optimal PAE mapping
55
50
45
Data taken on loadpull
fixture with no harmonic
tuning
Opt PAE
P1dB
P2dB
40
35
30
15
20
25
30
35
Vdd (V)
40
45
50
55
PAE (%)
Gain (dB)
GaN Drain Modulation Performance
(ABC Model*)
Pout (dBm)
Pout (dBm)
Assumes Linear relationship between Vdd and Pin
Peak PAE Point: Z = 4.00 + j*4.60 Ohms
Avg PAE = 68.19%, Avg Pout = 47.30 dBm, Avg Gain = 18.69 dB
Did not exceed 4.5 dB compression
*See Asbeck P.et al., “Augmented Behavioral Characterization for Modeling the Nonlinear Response of Power Amplifiers”,IEEE MTT-S Digest 2002
GaN Advantages in RF Power
Enabling the Application Space
Wide Bandwidth
High
Impedance
GaN-on-SiC
S
G
GaN
SiC
Multi-band
Operation
Configurable
Radios
High Efficiency
D
Low
Capacitance
Enables High
Efficiency Circuit
Techniques
OEM Amplifier Benefits
Smaller
Heatsink
High Power
High Breakdown
Voltage
High Power
Density
High Thermal
Conductivity
Compact
HPAs
Reduced: (1) size/complexity
(2) cooling
(3) weight and
(4) cost