Demoboard For BGA2003

Philips Semiconductors B.V.
Gerstweg 2, 6534 AE Nijmegen, The Netherlands
Report nr.
: RNR-T45-98-B-0709
Author
: R. Damen
Date
: 1998-October-30
Department
: Philips Semiconductors
Product Group : Discrete SemiConductors - Nijmegen (Netherlands)
Copy
:
APPLICATION NOTE
DEMOBOARD FOR BGA2003
•
Description of product
BGA2003: RF transistor with internal bias circuit. Benefit is lower component count, internal
compensation for temperature and diffusion spread.
•
Application Area
Low noise amplifiers for CDMA, DECT, GSM, PCS with low component count.
•
Presented Application
The application presents a low noise amplifier for CDMA at 1930-1990 MHz. Supply voltage
is 3V and supply current 10 mA. Only output matching is needed.
•
Main results
An amplifier has been designed and tested with >12.3 dB gain, IP3in=5 dBm,
VSWRin,out<1:2, and <2 dB Noise Figure at 1930-1990 MHz. 3 Volt, 10 mA supply.
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Philips Semiconductors B.V.
Abstract
Philips’ double poly fifth generation technology makes it possible to design high performance MMICs
(Microwave Monolithic Integrated Circuits). The advantage of such MMICs is a higher functionality
and a lower component count for high frequency applications.
This application note describes a design made with the BGA2003. The BGA2003 is a high
frequency transistor with integrated bias and control input.
The application described here is specially intended as CDMA LNA (Low Noise Amplifier) for the
1930-1990 MHz frequency region. The design was intended to show the following performance:
Gain > 12dB, NF < 2 dB, IP3in > +2 dBm, VSWRin,out < 1:2, Vsupply = 3V.
The following appendices can be found next:
-Circuit diagram and layout drawing
-Component values
-Measured results
-Conclusions and recomendations
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Philips Semiconductors B.V.
Circuit diagram and Layout drawing:
Vsupply
Vcontrol
C1
R2
in
Lout
R1
out
Cout
Cin
BGA2003
Component Values
Component
R1
R2
C1
Cin
Lout
Cout
uS1
MMIC
PCB
Value
22
2200
8.2pF
8.2pF
3.9nH
1.0pF
BGA2003
-
Type
0603 Philips
0603 Philips
0603 Philips
0603 Philips
0603 TDK MLG1608
0603 Philips
PCB-stripline 50Ω, via
Philips SOT343R2
FR4
Comment
Supply decoupling
Current setting
RF-short to ground
Input match, DC-decoupling
Output match
Output match
see figure below
ε R ~ 4.6, H = 0.5 mm
Stripline and via dimensions
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Philips Semiconductors B.V.
Measured values:
Vsupply = 3V, Vcontrol = 3V, Isupply = 9.4 mA, Icontrol = 0.84 mA
VSWRin
VSWRout
S21
S12
IP3in
NF
@ 1930 MHz
1.85
1.53
12.6 dB
-17.5 dB
+5
@ 1990 MHz
1.81
1.85
12.2 dB
-17.1 dB
+5.3
2 dB
1.9 dB
remark:
Pin=-25 dBm,
∆f=1 MHz
Conclusions and recomendations:
From the measured results it can be found that the desired performance can be delivered.
The IP3 is even a lot higher than required. Therefore one could try to lower the current in order
to have a less power consuming application. Because the gain would go down and matching
components on the input would be necessary to compensate for this, that approach was not
used in this design.
When evaluating the demoboard, one might find that the LNA is oscillating when both input
and output are open, and when all DC voltages are applied. Under normal operating
conditions (VSWRin,out< 1:7) there is however no problem.
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