STMicroelectronics
Quad-band GSM Power Amplifier by optimized BCD RFLDMOS
Andrea Pallotta – FTM Smart Power & HV Tech. Department
IEEE Topical Workshop on Power Amplifiers for Wireless Communications, San Diego 15-17 Jan. 2006
ER S T
Reduced Electrosmog Society Technology
This work has been supported and founded by the Italian Research and University Ministry (MIUR) throughout the project:
2ER S T
RF-LDMOS Cross-section
Parameter Value Test Condition BVDSS [V] 16 IDS = 0.01 nA/µm IOFF [pA/µm] <1 VDS = 5 V
VGS = 0 Ron*W [Ω*mm] 2.8 VGS = 3.3 V
VDS = 0.1 V Gm/W [mS/mm] 200 VDS = 3.5 V ISAT/W [mA/mm] 480 VDS = 3.5 V FT [GHz] 18 VDS = 3.5 V
Table I
3ER S T
W=2.8mm RF-LDMOS load-pull measurements
4ER S T
W=2.8mm RF-LDMOS W-CDMA ACPR measurements
5ER S T
RF-LDMOS sub circuit model
6ER S T
W=6 mm RF-LDMOS model vs. measurements
7ER S T
W=12mm RF-LDMOS model vs. measurements
8ER S T
Final power RF-LDMOS transistors for GSM PA
W=24mm
W=12mm
• 120 fingers for each active area
• each finger is 25 µm long
9ER S T
Final power transistor test board
•SMD size: 0.75x1.5 mm (0603)•Board size: 38x51 mm (BT laminate)•Output Matching Network implemented for Harmonic Control
RF out50 ΩRF in
50 Ω
Vg
VDD
10ER S T
CAD optimization maximizing PAE and Pout (W=12mm)
RF out50 ΩRF in
50 Ω
Vg
VDD
1.75 GHzPout = 32.5 dBm
PAE = 48%
1.88 GHzPout = 32 dBm
PAE = 51%
11ER S T
50Ω-50Ω matched final power LDMOS
20
25
30
35
10 12 14 16 18 20 22 24 26Pin (dBm)
Pout
(dB
m)
1520253035404550556065
PAE
(%)
0
5
10
15
20
25
30
35
16 18 20 22 24 26Pin (dBm)
Pout
(dbm
), G
ain
(dB
)
20
25
30
35
40
45
50
55
PAE
(%)
12ER S T
Quad-band GSM850-900 and GSM 1800-1900 RF PA on PCB in order to validate the RF-BCD technology process
1st 2nd 3rd
Preamp = 0.8 x 1.4 mm Power = 0.6 x 1.3 mm
GSM850-900 board = 38 x 51 mm
1st 2nd 3rd
Preamp = 1 x 1.8 mm Power = 1 x 1.8 mm
DCS-PCS board = 38 x 51 mm
13ER S T
GSM850-900, DCS-PCS Circuit Schematics
LaminatePCB
GSM-850
GSM-900
W=0.1mmM = 8 W=3mm
MOS50 Ω
LaminatePCB
Sidie
W=12mm
50 Ω
Sidie
Sidie
DCSPCS
RF IN
RF OUTM4
Vc
RFinT1 T2 T3 RFout
Bias ControlBias ControlBias Control
GSM Driver
50 Ω50 Ω
Si
die
Si
die
M2
M3M1M4
14ER S T
GSM850 RF PA main performances
Pin=6dBmPout=35.3dBmPAE=47%
15ER S T
GSM900 RF PA main performances
Pin=6dBmPout=35.2dBmPAE=55%
16ER S T
GSM900 RF PA Pout and PAE over frequency
31
31.5
32
32.5
33
33.5
34
34.5
35
35.5
36
840 860 880 900
Frequency (MHz)
Pout
(dB
m)
40
42
44
46
48
50
52
54
56
58
60
PAE
(%)
PoutPAE
17ER S T
DCS RF PA main performances
Pin=6dBmPout=33dBmPAE=51.4%
18ER S T
PCS RF PA main performances
Pin=6dBmPout=32.1dBmPAE=47.7%
19ER S T
Second harmonic level in the upper band
20
22.5
25
27.5
30
32.5
35
1.65 1.7 1.75 1.8 1.85 1.9 1.95 2
Frequency (GHz)
Pou
t (dB
m) @
Pin
= 6
dBm
15
25
35
45
55
65
75
H2 (d
Bc)
Target spec
20ER S T
1.75GHz: 2-Tone IM3 vs. Input Power
0
10
20
30
40
-8 -3 2 7 12
Pin (dBm)
Pout
, 2-to
ne IM
3 (d
Bm
)
2− tone ∆ f = 5 MHz
21ER S T
Pout and DC drain current vs. VSWR > 8:1 all phases @ 5 V
22ER S T
DCS PA on PCB board detail
23ER S T
GSM850-900, DCS-PCS on board summary
47 / 474751475247PAE (%)
32.5 / 323232.5353535POUT (dBm)
033033PIN (dBm)
SOA*DCS/PCS(module)
PCS(board)
DCS(board)
SOA*GSM
(module)
GSM-900(board)
GSM-850(board)
1.721.741.761.781.801.821.841.861.881.90
1.70
1.92
10152025303540
5
45
-12
-10
-8
-6
-14
-4
Freq, GHz
S21
Mag
(dB)
S11 Mag (dB)
S-parameters DCS-PCS5
1015202530354045
800 840 880 920 960 1000
Freq (GHz)
S21
Mag
(dB
)
-20-18-16-14-12-10-8-6-4-20
S11
Mag
(dB
)
S-parameters GSM850-900
* SOA: State Of the Art LDMOS based GSM PA module available on the market
24ER S T
RF front end module moves towards high integration level => LTCC
25ER S T
8x8mm Quad-Band GSM850-900 & DCS-PCS PA on LTCC