900MHz LOW NOISE AMPLIFIER WITH THE BFG410W

H
Philips Semiconductors B.V.
Gerstweg 2, 6534 AE Nijmegen, The Netherlands
Report nr.
Author
Date
Department
: RNR-T45-96-B-770
: T. Buss
: 20-Jan-00
: P.G. Transistors & Diodes, Development
900MHz LOW NOISE AMPLIFIER
WITH THE BFG410W
Abstract:
This application note contains an example of a Low Noise Amplifier with the new BFG410W Double Poly
RF-transistor. The LNA is designed for a frequency f=900MHz. The Noise Figure NF~1.4dB at f=900MHz
and the gain S21 ~14dB.
Appendix I: 900MHz LNA circuit
Appendix II: Printlayout and list of used components & materials
Appendix III: Results of simulations and measurements
1
H
Philips Semiconductors B.V.
Introduction:
With the new Philips silicon bipolar double poly BFG400W series, it is possible to design low noise
amplifiers for high frequency applications with a low current and a low supply voltage. These amplifiers are
well suited for the new generation low voltage high frequency wireless applications. In this note a first study
of such an amplifier will be given. This amplifier is designed for a working frequency of 900MHz.
Designing the circuit:
The circuit is designed to show the following performance:
transistor: BFG410W
Vce=2V, Ic =2mA, VSUP~3.3V
freq=900MHz
Gain~15dB
NF<=1.3dB
VSWRi<1:2
VSWRo<1:2
In the simulations the effect of extra RF-noise caused by the SMA-connectors was omitted, so in the practical
situation the NF is ~0.1dB higher. This LNA is not optimised for the highest IP3. The IP3 can be optimised by:
I. an extra series RC-decoupling of the base to the ground
II. increasing IC
With the solution I. two extra components are necessary, and with solution II, the Noise Figure of the LNA
increases and the optimum source impedance also.
The in- and outputmatching is realised with a LC-combination. Also extra emitter-inductance on both emitterleads (µ-strips) are used to improve the matching and the Noise Figure.
Designing the layout:
A lay-out has been designed with HP-MDS. Appendix II contains the printlayout.
Measurements:
Simulations (with realistic RF-models of al used parts) and measurements of the total circuit
(epoxy PCB) are done (Appendix III).
2
H
Philips Semiconductors B.V.
Appendix I: Schematic of the circuit
C6
C3
R5
C4
R1
+VSUP
C2
R3
R4
Coil_2
Coil_1
R2
OUT
50Ω
C5
IN
50Ω
C7
W1
C1 BFG410W
µS4:
µS4
L1
L2
µS4
D1
L3
W2
Figure 1: LNA circuit
900MHz LNA Component list:
Component:
Value:
Comment:
R1
R2
R3
R4
R5
C1
C2
C3
C4
C5
C6
C7
Coil_1
Coil_2
µs4
Bias.
Better RF-stability (K>1).
RF-block.
Cancelling HFE-spread.
To improve IP3-performance
Input match.
900MHz short.
900MHz short.
RF-short
Output match.
To improve IP3-performance
Better RF-stability (K>1).
Input match.
Output match.
Emitter induction: µ-stripline + via
47
120
22
560
100
2.2
27
27
1
1.5
100
0.47
12
15
(next
KΩ
Ω
Ω
Ω
Ω
pF
pF
pF
nF
pF
nF
pF
nH
nH
table)
3
H
Philips Semiconductors B.V.
µS4 Emitter induction (µ-stripline + via):
Name Dimension Description
L1
2.0mm
length µ-stripline; Z0 ~48Ω (PCB: εr ~4.6, H=0.5mm)
L2
1.0mm
length interconnect stripline and via-hole area
L3
1.0mm
length via-hole area
W1
0.5mm
width µ-stripline
W2
1.0mm
width via-hole area
D1
0.4mm
diameter of via-hole
4
H
Philips Semiconductors B.V.
Appendix II: Printlayout and list of used components & materials
RFin
C1
C7
R5 C6
C5
RFout
L1
R2
C2
C4
L2
R1
Vsup
R4
R3
C3
Figure 2: 900MHz LOW NOISE AMP. PRINT LAYOUT
Component list:
Component:
Value:
size:
R1
R2
R3
R4
R5
C1
C2
C3
C4
C5
C6
C7
L1
L2
PCB
47
KΩ
120 Ω
22
Ω
560 Ω
100 Ω
2.2 pF
27
pF
27
pF
1
nF
1.5 pF
100 nF
0.47 pF
12
nH
15
nH
εr~4.6, H=0.5mm
0603 Philips
0603 Philips
0603 Philips
0603 Philips
0805 Philips
0603 Philips
0603 Philips
0603 Philips
0603 Philips
0603 Philips
0805 Philips
0603 Philips
0805CS Coilcraft
0805CS Coilcraft
FR4
5
H
Philips Semiconductors B.V.
Appendix III: Results of simulations en measurements
BFG410W, VCE=2V, IC=2mA:
Simulation (HP-MDS):
2
|S21| [dB]
14.6
VSWRi
2.0
VSWRo
2.4
Noise Figure [dB]
1.3
IP3 [dBm] (input)
-
Measurements PCB:
14.0
1.9
2.3
*)
1.4
-9
Comment:
∆f=100KHz
*)
: The Noise Figure of the PCB is higher than the simulations (~0.1 dB). This is caused by the influence of
the SMA-connectors and the microstrips on the epoxi PCB.
CMP230
MSVIA
W=Wvia
OD=0.4
SUBST=s10mil
mm
W=Wvia
L=Lvia
CMP231
MSTL
SUBST=s10mil
L=1 nH
CMP265
L
CMP427
R_nor
1 2
CMP263
C
R1=100
model cap. 1nF
C=1 nF
L=1 nH
CMP417
L
CMP286
MSVIA
LOW NOISE AMP. WITH [email protected]/5mA
SUBST=s10mil
OD=0.4
W=Wvia
mm
CMP264
R
L=Lvia
W=Wvia
CMP287
MSTL
CMP418
C
R=0.3 OH
C=100 nF
SUBST=s10mil
R1=22 OH
R1=560 OH
1 2
CMP419
R
CMP289
cmc_0603_phil
Ccmc=Contkop
W=0.5 mm
L=0.5 mm
SUBST=s10mil
R=0.3 OH
CMP428
R_nor
L=100 uH
CMP405
MSTL
Lx=Lin
W=W3
L=L3
SUBST=s10mil
SUBST=s10mil
L=0.5 mm
W=0.5 mm
[email protected]/5mA
CMP257
TWOPORT
CMP383
MSTL
SUBST=s10mil
L=3 mm
W=0.5
CMP409mm
CMP203
cmc_0603_phil
MSTL
smd
DATA=BFG425W_5mA.DATA.,FREQ=freq
W=W3CMP408
MSTL
L=L3
SUBST=s10mil
Lx=Lout
R1=Rout
CMP358
MSTL
CMP394
coilcraft_l1008_cs
CMP197
cmc_0603_phil
SUBST=s10mil
L=0.5 mm
W=0.5 mm
1
2
CMP431
SUBST=s10mil
R_nor
L=L4
W=W4
Ccmc=Cin
CMP359
MSTL
CMP18
PORT_SPAR
vswri=(1+mag(s11))/(1-mag(s11))
vswro=(1+mag(s22))/(1-mag(s22))
Cin=(4.7) pF
Cout=(2.7) pF
Lin=(10) nH
Lout=(10) nH
EQUATION Contkop=(27) pF
EQUATION
EQUATION
EQUATION
EQUATION
L1=(2.5) mm
L2=(1) mm
L3=(0.5) mm
L4=(0.2) mm
EQUATION Lvia=(0.25) mm
EQUATION Wvia=(1) mm
EQUATION Wvia_e=(1) mm
EQUATION W3=(0.5) mm
EQUATION W4=(0.5) mm
SUBST=s10mil
L=0.5 mm
W=0.5 mm
CMP438
cmc_0603_phil
CMP350
MSTL
CMP351
MSTL
W=0.5
L=L1
SUBST=s10mil
mm
W=0.5
L=L1
SUBST=s10mil
mm
CMP227
MSTL
W=W50_Ohm
L=6 mm
SUBST=s10mil
HU=1.0E+3 m
T=35um
CMP252
MSTAPER
SUBST=s10mil
W1=Wvia_e
L=L2
H=0.5mm
W1=Wvia_e
SUBST=s10mil
L=L2
EQUATION W50_Ohm=(0.9) mm
EQUATION Rout=(27)
EQUATION Cce=(0.47) pF
CMP180
MSVIA
W=Wvia_e
OD=0.4 mm
CMP210
MSVIA
W=Wvia_e
OD=0.4 mm
SUBST=s10mil
SUBST=s10mil
6
Ccmc=Cout
CMP403
MSTL
PORTNUM=2
CMP270
PORT_SPAR
R=50
JX=0
AGROUND
CMP5
MSSUBSTRATE
W2=0.5 mm
W2=0.5 mm
CMP250
MSTAPER
Ccmc=Cce
SUBST=s10mil
ER=4.6
MUR=1
COND=5.8e07
ROUGH=10 um
TAND=0.02
W=Wvia
L=Lvia
SUBST=s10mil
Ccmc=Contkop
1 2
CMP401
PORTNUM=1 MSTL
R=50
JX=0
EQUATION
EQUATION
EQUATION
EQUATION
AGROUND
EQUATION
EQUATION
AGROUND
CMP406
MSTL
CMP236
MSTL
CMP399
coilcraft_l1008_cs
CMP281
cmc_0603_phil
CMP429
R_nor
1 2
R1=47k
smd
W=W50_Ohm
L=6 mm
SUBST=s10mil
CMP235
L
1 2
CMP430
R_nor
CMP266
MSVIA
SUBST=s10mil
OD=0.4 mm
W=Wvia
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