California Eastern Laboratories
APPLICATION NOTE
AN1037
Optimizing a Silicon Bipolar LNA Performance
for Blue Tooth Applications
Abstract
The NE662M04 is NEC's latest generation of Silicon Bipolar
junction RF-transistor, using a state-of-the-art UHSO 25
GHz fT wafer process. It provides excellent low voltage/low
current performance and is ideally suited for low noise mobile
applications. This application note describes a low-noise
amplifier designed for the Blue Tooth RF standard
specifications per Table 1. The emphasis is set on achieving
a low noise, high gain performance while keeping current
consumption at a minimum and a fairly good input and output
match.
General information, test results, circuit schematic, board
layout and Billing of Material is enclosed as a reference.
California Eastern Laboratories also provides this circuit as
an evaluation board to its customers for quick turn around
design cycles.
LNA Design and Matching Network
In order to achieve the specification and provide the appropriate
matching, the design uses an inductive emitter feedback
through a high impedance printed transmission line and all
other matching elements are lumped components. The
approximately 0.7 nH emitter inductance provides a few
advantages: It allows for matching the device for minimum
noise figure performance while keeping an acceptable input
matching, it enhances the in-band stability performance of the
Item
1
2
3
4
5
6
7
8
9
10
11
LNA and to some lesser extent, it improves the linearity of the
device. However, the trade-off is reduced gain and the potential
for high frequency oscillations. The latter can easily be
negated by carefully choosing the out of band matching.
The bias network is a simple base resistor that will fix the
current to 5 mA. In circuits where temperature stability or
reduced sensibility to manufacturing variations is more of an
issue, an active stabilization bias can be used with commonly
available electronic bipolar transistors.
The input matching network comprises only C1 and L1 and is
set to achieve ΓOPT from a 50Ω input load. L1 is also used as
the choke that brings the base current to the transistor and is
RF grounded by C2. The long transmissions line to and from
C3 are only additional DC chokes to bias the device. The
output matching is a simple capacitive match through C7 that
provides better than 1.5:1 match. L2 is the RF choke grounded
through C5 and further choking is provided by the printed
inductive transmission line. The circuit schematic, layout and
assembly drawing are available in Figures 1, 2, 3 and the
Billing of Material is displayed in Table 2.
The matching has been optimized for the particular Blue
Tooth receiving band. However, the PCB board can be used
in a wide range of applications, from 460 MHz to about 3 GHz
for a number of devices, providing that an appropriate matching
network is synthesized.
The 2.4 GHz LNA results are available in Figure 4-6 and
Table 3.
Parameters
Specifications
Test
LNA Section
Results
Voltage
3
3
Current
5
5
Operating Frequency
2400-2483.5
1930-1990
Gain
10
12
NF
1.5
1.3
Input IP3
0
3
1 dB Compression Point
-5.0
0
Input VSWR (50 Ohms)
2.5:1 (-9.5 dB)
-10
Output VSWR (50 Ohms)
1.5:1 (-14 dB)
-15
Stability at all Frequencies Unconditionally Stable Unconditionally Stable
Operating Temperature
-40 to +80
-40 to +80
Units
Notes
V
mA
GHz
dB
dB
dBm
dBm
°C
Low Voltage
Low Current
US/European Bands
Table 1. Bluetooth Low Noise Amplifier: Specifications and Test Results.
Low Noise
High IP3
AN1037
EVALUATION BOARD PARTS LIST
QTY
1
1
1
1
1
2
1
2
1
1
1
2
2
1
PART OR
IDENTIFYING NO.
TF-100413
LL 1608-FH5N6S
LL 1608-FH15NJ
LL 1608-FH2N7S
MCR03J303JK
MCH185A121JK
MCH185A4R7CK
MCH185A102JK
MCH185C300JK
881-6116
NE662M04
2340-6111 TG
2052-1215-00
FD-100722
NOMENCLATURE OR
DESCRIPTION
L1
L2
L3
R1
C2, C5
C1
C3, C4
C7
C6
U1
P1
J1, J2
PCB
ITEM
MATERIAL/SPECIFICATION
NO.
NE34018-EVAL TEST FIXTURE BLOCK 14
5.6 nH INDUCTOR TOKO
13
15 nH INDUCTOR TOKO
12
2.7 nH INDUCTOR TOKO
11
0603 30 K OHM RES ROHM
10
0603 120 pF CAP ROHM
9
0603 4.7 pF CAP ROHM
8
0603 1000 pF CAP ROHM
7
0603 30 pF CAP ROHM
6
4.7 µF CAP AVX
5
IC NEC
4
PIN HEADER 3M
3
OSM JACK OMNI SPECTRA
2
NE622M04-EVAL FAB. DRAWING
1
Table 2. LNA Billing of Material
1.100
1.500
NE662M04-EVAL
100722
Figure 2. Printed Circuit Board Layout
Figure 3. LNA Assembly Drawing
AN1037
NE662M04
W = 57 mils
L = 77 mils
C1
4.7 pF
W = 57 mils
L = 326 mils
RF IN
W = 57 mils
L = 53 mils
W = 57 mils
L = 198 mils
L3
2.7 nH
W = 57 mils
L = 139 mils
RF OUT
C7
30 pF
L2
15 nH
L1
56 nH
C2
120 pF
W = 10 mils
L = 70 mils
Via
Holes
C3
1000 pF
PC Board
28 mils Getek Board
0.5 Oz. Cu.
W = 10 mils
L = 70 mils
Via
Holes
C4
1000 pF
Printed Low
Frequency Inductors
+
R1
30 k
P1
VCC
C6
4.7 µF
Figure 1. NE662M04 Blue Tooth LNA Schematic
15
8
10
Output Power (dBm) and Gain (dB)
Gain (dB) and Return Loss (dB)
20
S21
10
1 2
5
0
-5
1
-10
1
S11
2
-15
S22
9
15
S21 { 1: 12.032 dB
2: 11.648 dB
-8.996 dB
S11 { 1:
2: -8.861 dB
-16.008 dB
S22 { 1:
2: -15.163 dB
2
7
5
6
0
5
4
-5
3
-10
2
-15
1
-20
-25
Start 1.000000000 GHz
S11
-20
-30
Stop 4.000000000 GHz
S21
-25
-20
-15
Input Power (dBm)
Figure 4. Measured Small Signal Performance
20
10
10
0
0
-10
-20
-20
-30
-30
-40
-40
-50
-50
-60
-60
-70
-80
-70
-90
-80
TOI
-20
-15
Input Power (dBm)
Average IM3
POUT
-10 -8
Average IM5
Figure 6. Linearity Performance
-90
Output Power (dBm)
Average (dBm) IM3
TOI Pavg-avg (dBm)
Average (dBm) IM5
-10
-25
0
S22
POUT
-100
-30
-10 -8
Efficiency
Gain
Figure 5. Output Power Performance
Power Added Efficiency (%)
25
AN1037
NE662M04-EVNF 24
Input Power
Output Power
Gain
Average
C / IM3
TOI
(dBm)
(dBm)
(dB)
(dBm)
IM3
(dBc)
Pavg-avg
(dBm)
Pavg-avg
-30.00
-29.00
-28.00
-27.00
-26.00
-25.00
-24.00
-23.00
-22.00
-21.00
-20.00
-19.00
-18.00
-17.00
-16.00
-15.00
-14.00
-13.00
-12.00
-11.00
-10.00
-9.00
-18.15
-17.20
-16.29
-15.22
-14.20
-13.23
-12.24
-11.25
-10.25
-9.26
-8.28
-7.29
-6.34
-5.36
-4.40
-3.46
-2.57
-1.69
-0.86
-0.14
0.51
1.04
11.85
11.80
11.71
11.78
11.80
11.77
11.76
11.75
11.75
11.74
11.72
11.71
11.66
11.64
11.60
11.54
11.43
11.31
11.14
10.86
10.51
10.04
-88.57
-87.54
-80.97
-78.80
-75.87
-72.48
-69.83
-66.67
-63.08
-60.93
-57.28
-54.46
-51.67
-48.44
-45.41
-42.37
-39.48
-35.86
-31.86
-27.81
-24.15
-21.04
70.50
70.42
64.59
63.50
61.58
59.16
57.67
55.33
52.75
51.66
48.91
47.09
45.16
42.83
40.67
38.59
36.34
33.58
30.25
26.83
23.66
21.00
17.18
18.09
15.91
16.45
16.50
16.27
16.68
16.33
16.04
16.57
16.09
16.17
16.07
15.80
15.60
15.51
15.02
14.52
13.51
12.45
11.34
10.46
Frequency: 2.400 GHz
VD: 2.999 V, ID = 5 mA
POUT at 1 dB: .168 dBm
Gain at 1 dB: 10.744 dB
Efficiency at 1 dB: 6.39 %
IIP3 at PIN = -21 dBm = +4.77 dBm
Noise Figure at 2.4 GHz = 1.15 dB
Table 3. Summary of Power Performance.
California Eastern Laboratories
Exclusive Agents for NEC RF, Microwave and Optoelectronic
semiconductor products in the U.S. and Canada
4590 Patrick Henry Drive, Santa Clara, CA 95054-1817
Telephone 408-988-3500 • FAX 408-988-0279 •Telex 34/6393
Internet: http:/WWW.CEL.COM
Information and data presented here is subject to change without notice.
California Eastern Laboratories assumes no responsibility for the use of
any circuits described herein and makes no representations or warranties,
expressed or implied, that such circuits are free from patent infingement.
© California Eastern Laboratories 02/20/2003