19-1786; Rev 1; 11/03
KIT
ATION
EVALU
E
BL
AVAILA
2.4GHz SiGe,
High IP3 Low-Noise Amplifier
General Description
Features
o
Low Noise Figure (2.0dB at 2450MHz)
o
High Gain: 16dB
o
Adjustable IP3 and Bias Current
o
Low-Power Standby Mode
o
On-Chip Output Matching
o
+2.7V to +5.5V Single-Supply Operation
o
Ultra-Small 6-Pin SC70 Package
MAX2644
The MAX2644 low-cost, high third-order intercept point
(IP3) low-noise amplifier (LNA) is designed for applica-
tions in 2.4GHz WLAN, ISM, and Bluetooth radio sys-
tems. It features a programmable bias, allowing the
input IP3 and supply current to be optimized for specif-
ic applications. The LNA provides up to +1dBm input
IP3 while maintaining a low noise figure of 2.0dB and a
typical gain of 16dB.
The MAX2644 is designed on a low-noise, advanced
silicon-germanium (SiGe) technology. It operates with a
+2.7V to +5.5V single supply and is available in an
ultra-small 6-pin SC70 package.
________________________Applications
Bluetooth
802.11 WLAN
Home RF
Satellite CD Radio
2.4GHz ISM Band Radios
2.4GHz Cordless Phones
Wireless Local Loop (WLL)
MAX2644EXT-T
PART
Ordering Information
TEMP RANGE
-40°C to +85°C
PIN-
PACKAGE
6 SC70
TOP
MARK
AAG
Typical Operating Circuit
R
BIAS
1.2kΩ
V
CC
BIAS
BIAS
V
CC
Pin Configuration
TOP VIEW
C1
33pF
RF INPUT
L1
3.3nH
RFIN
RFOUT
RF OUTPUT
BIAS
1
6
RFOUT
GND
2
MAX2644
5
GND
RFIN
3
4
V
CC
MAX2644
GND
SC70-6
________________________________________________________________
Maxim Integrated Products
1
For pricing, delivery, and ordering information, please contact Maxim/Dallas Direct! at
1-888-629-4642, or visit Maxim’s website at www.maxim-ic.com.
2.4GHz SiGe,
High IP3 Low-Noise Amplifier
MAX2644
ABSOLUTE MAXIMUM RATINGS
V
CC
to GND ..............................................................-0.3V to +6V
RFIN, RFOUT to GND…......................................................±0.3V
RFIN Power (50Ω source) ................................................+5dBm
BIAS to GND ................................................................0 to +0.3V
Operating Temperature Range ...........................-40°C to +85°C
Maximum Junction Temperature .....................................+150°C
Continuous Power Dissipation (T
A
= +70°C)
6-Pin SC70 (derate 3.1mW/°C above +70°C) ..............245mW
Storage Temperature.........................................-65°C to +150°C
Lead Temperature (soldering, 10s) .................................+300°C
Stresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. These are stress ratings only, and functional
operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to
absolute maximum rating conditions for extended periods may affect device reliability.
DC ELECTRICAL CHARACTERISTICS
(V
CC
= +2.7V to +5.5V, R
BIAS
= 1.2kΩ, no RF signal applied, R
FIN
and R
FOUT
are AC-coupled and terminated to 50Ω, T
A
= -40°C to
+85°C. Typical values are at V
CC
= +3.0V, T
A
= +25 °C, unless otherwise noted.) (Note 1)
PARAMETER
Supply Voltage
R
BIAS
= 3.9kΩ
Operating Supply Current
R
BIAS
= 1.2kΩ, T
A
= +25°C
R
BIAS
= 1.2kΩ, T
A
= -40°C to +85°C
R
BIAS
= 750Ω
Standby Supply Current
R
BIAS
is unconnected, T
A
= +25°C, V
CC
= 3.3V
10.2
100
µA
CONDITIONS
MIN
2.7
2.7
7.0
9.7
11.0
mA
TYP
MAX
5.5
UNITS
V
AC ELECTRICAL CHARACTERISTICS
(MAX2644 EV kit, V
CC
= +3.0V, f
RFIN
= 2450MHz, P
RFIN
= -30dBm, input and output are terminated to 50Ω, R
BIAS
= 1.2kΩ,
T
A
= +25°C, unless otherwise noted.) (Note 2)
PARAMETER
Operating Frequency
Gain (Note 4)
Gain Variation Over Temperature
Input Third-Order Intercept Point
(Note 5)
Input 1dB Compression Point
Noise Figure
Input Return Loss
Output Return Loss
Reverse Isolation
(Note 6)
T
A
= -40°C to +85°C
R
BIAS
= 750Ω
R
BIAS
= 1.2kΩ
R
BIAS
= 3.9kΩ
(Note 3)
CONDITIONS
MIN
2400
15
17
±0.7
-4
-3
-8
-13
2.0
-15
-10
-30
2.5
dBm
dB
dB
dB
dB
dBm
±1.0
TYP
MAX
2500
UNITS
MHz
dB
dB
Note 1:
Devices are production tested at T
A
= +25°C. Minimum and maximum values are guaranteed by design and characterization
over temperature and supply voltages.
Note 2:
Min/Max limits are guaranteed by design and characterization.
Note 3:
The part has been characterized at the specified frequency range. Operation outside this range is possible but not guaranteed.
Note 4:
Excluding PC board losses (0.3dB at the input and 0.3dB at the output of the MAX2644 EV kit).
Note 5:
Measured with two input tones (f
1
= 2445MHz, f
2
= 2455MHz) both at -30dBm per tone. Input IP3 can be improved to
+1dBm with circuit shown in Figure 2.
Note 6:
Excluding PC board losses (0.3dB typical at the input of the MAX2644 EV kit).
2
_______________________________________________________________________________________
2.4GHz SiGe,
High IP3 Low-Noise Amplifier
MAX2644
Typical Operating Characteristics
(P
RFIN
= -30dBm, Z
S
= Z
L
= 50Ω, V
CC
= +3.0V, f
RFIN
= 2450MHz, R
BIAS
= 1.2kΩ, T
A
= +25°C, unless otherwise noted.)
SUPPLY CURRENT vs. SUPPLY VOLTAGE
MAX2644 toc01
SUPPLY CURRENT vs. R
BIAS
MAX2644 toc02
GAIN vs. SUPPLY VOLTAGE
21
20
19
GAIN (dB)
18
17
16
15
T
A
= +25°C
T
A
= +85°C
R
BIAS
= 1.2kΩ
MAX2644 toc03
14
12
R
BIAS
= 1.2kΩ
T
A
= +85°C
13
11
SUPPLY CURRENT (mA)
9
7
5
3
1
T
A
= -40°C
T
A
= +85°C
T
A
= +25°C
22
SUPPLY CURRENT (mA)
10
8
6
4
2
0
2.5
3.0
3.5
4.0
4.5
5.0
5.5
SUPPLY VOLTAGE (V)
T
A
= +25°C
T
A
= -40°C
T
A
= -40°C
14
13
12
2.0
2.5
3.0
3.5
4.0
2.5
3.0
3.5
4.0
4.5
5.0
5.5
0.5
1.0
1.5
R
BIAS
(kΩ)
SUPPLY VOLTAGE (V)
GAIN vs. FREQUENCY
MAX2644 toc04
GAIN vs. R
BIAS
MAX2644 toc05
INPUT AND OUTPUT RETURN LOSS
vs. FREQUENCY
-2
-4
REVERSE ISOLATION (dB)
-6
-8
-10
-12
-14
-16
-18
INPUT RETURN LOSS
OUTPUT RETURN LOSS
R
BIAS
= 1.2kΩ
MAX2644 toc06
20
19
18
17
GAIN (dB)
R
BIAS
= 1.2kΩ
T
A
= -40°C
19
18
17
GAIN (dB)
T
A
= -40°C
0
16
15
14
13
12
11
10
2200
2300
2400
2500
2600
2700
FREQUENCY (MHz)
T
A
= +25°C
T
A
= +85°C
16
15
14
13
0.5
T
A
= +25°C
T
A
= +85°C
-20
1.0
1.5
2.0
2.5
3.0
3.5
4.0
2200
2300
2400
2500
2600
2700
R
BIAS
(kΩ)
FREQUENCY (MHz)
REVERSE ISOLATION vs. FREQUENCY
MAX2644 toc07
NOISE FIGURE vs. FREQUENCY
MAX2644 toc08
NOISE FIGURE vs. TEMPERATURE
R
BIAS
= 1.2kΩ
3.5
3.0
NOSIE FIGURE (dB)
2.5
2.0
1.5
1.0
0.5
0
-40
-15
10
35
60
85
MAX2644 toc09
-20
-25
REVERSE ISOLATION (dB)
R
BIAS
= 1.2kΩ
4.0
3.5
3.0
NOSIE FIGURE (dB)
2.5
2.0
1.5
1.0
0.5
4.0
R
BIAS
= 1.2kΩ
T
A
= -40°C
-30
-35
-40
-45
-50
2200
2300
2400
2500
2600
2700
FREQUENCY (MHz)
T
A
= +25°C
T
A
= +85°C
0
2350
2400
2450
FREQUENCY (MHz)
2500
2550
TEMPERATURE (°C)
_______________________________________________________________________________________
3
2.4GHz SiGe,
High IP3 Low-Noise Amplifier
MAX2644
Typical Operating Characteristics (continued)
(P
RFIN
= -30dBm, Z
S
= Z
L
= 50Ω, V
CC
= +3.0V, f
RFIN
= 2450MHz, R
BIAS
= 1.2kΩ, T
A
= +25°C, unless otherwise noted.)
OUTPUT POWER vs. INPUT POWER
MAX2644 toc10
IIP3 vs. R
BIAS
MAX2644 toc11
INPUT P
1dB
vs. R
BIAS
-12
-13
INPUT P
1dB
(dBm)
-14
-15
-16
-17
T
A
= -40°C
-18
-19
T
A
= +25°C
T
A
= +85°C
MAX2644 toc12
10
5
OUTPUT POWER (dBm)
0
-5
-10
-15
-20
-30
-25
-20
-15
-10
-5
0
INPUT POWER (dBm)
-1
-2
-3
IIP3 (dBm)
T
A
= +85°C
T
A
= +25°C
-11
R
BIAS
= 750Ω
R
BIAS
= 1.2kΩ
R
BIAS
= 3.9kΩ
-4
-5
-6
-7
-8
-9
0.5
1.0
1.5
2.5
R
BIAS
(kΩ)
2.0
3.0
3.5
4.0
T
A
= -40°C
0.5
1.0
1.5
2.5
R
BIAS
(kΩ)
2.0
3.0
3.5
4.0
Pin Description
PIN
1
2, 5
3
4
6
NAME
BIAS
GND
RFIN
V
CC
RFOUT
DESCRIPTION
Resistor Bias Control. Connect a resistor, R
BIAS
, from BIAS to ground. R
BIAS
sets IP3 and supply
current. The current through this pin is approximately 60mV divided by R
BIAS
(see
Applications
Information).
Ground. For optimum performance, provide a low-inductance connection to the ground plane.
Amplifier Input. AC-couple to this pin with a DC blocking capacitor. External matching network is
required for optimum performance.
Supply Voltage. Bypass with a capacitor directly to ground at the supply pin. Refer
to V
CC
Line
Bypassing
section for more information.
Amplifier Output. AC-coupled internally.
RFOUT
1
R1
1.2kΩ
2
BIAS
U1
GND
RFOUT
6
SMA
MAX2644
GND
5
GND
RFIN
SMA
L1
3.3nH
C1
33pF
Length = 400mils
3
RFIN
V
CC
4
C3
2.2pF
C2
33pF
VCC
GAIN: 17dB
IIP3: -3dBm
Figure 1. High Gain Design
4
_______________________________________________________________________________________
2.4GHz SiGe,
High IP3 Low-Noise Amplifier
MAX2644
1
R1
1.2kΩ
2
BIAS
U1
GND
RFOUT
6
L2
3.9nH
RFOUT
SMA
MAX2644
GND
5
GND
RFIN
SMA
L1
3.3nH
C1
33pF
3
RFIN
V
CC
4
Length = 400mils
C3
15pF
C2
33pF
V
CC
GAIN: 16dB
IIP3: +1dBm
Figure 2. High Linearity Design
BIAS
BIAS
MAX2644
MAX2644
(a)
(b)
Figure 3. Recommended MAX2644 Standby Configurations
Applications Information
Input Matching
Input matching is required for optimum performance.
The MAX2644 requires a simple LC matching network,
as shown in the
Typical Operating Circuit.
To further
reduce cost and external component count, replace the
external inductor with a microstrip transmission line.
The
Typical Operating Circuit
shows the recommended
input matching network for the MAX2644 at 2450MHz.
These values are optimized for best simultaneous gain,
noise figure, and return loss performance.
V
CC
Line Bypassing
Bypassing the V
CC
line is necessary for optimum
gain/linearity performance. A transmission line and two
capacitors are required, as shown in the schematics in
Figures 1 and 2. The optimum dimensions and posi-
tions of the components are as follows: the output
transmission line dimension is 0.532in (length)
✕
0.012in
(width); the distance from C2 to the IC is 0.352in; and
the distance from C3 to the IC is 0.041in. Please refer
to Figures 1 and 2 for component values.
_______________________________________________________________________________________
5
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