General Description
The MAX2640/MAX2641 are low-cost, ultra-low-noise
amplifiers designed for applications in the cellular, PCS,
GPS, and 2.4GHz ISM frequency bands. Operating from
a single +2.7V to +5.5V supply, these devices consume
only 3.5mA of current while providing a low noise figure,
high gain, high input IP3, and an operating frequency
range that extends from 300MHz to 2500MHz.
The MAX2640 is optimized for 300MHz to 1500MHz
applications, with a typical performance of 15.1dB gain,
input IP3 of -10dBm, and a noise figure of 0.9dB at
900MHz. The MAX2641 is optimized for 1400MHz to
2500MHz applications, with a typical performance of
14.4dB gain, an input IP3 of -4dBm, and a noise figure of
1.3dB at 1900MHz.
These devices are internally biased, eliminating the need
for external bias resistors and chokes. In a typical appli-
cation, the only external components needed are a two-
element input match, input and output blocking capaci-
tors, and a VCC bypass capacitor.
The MAX2640/MAX2641 are designed on a high-frequen-
cy, low-noise, advanced silicon-germanium process and
are offered in the space-saving, 6-pin SOT23 package.
Applications
●315MHz/400MHz/900MHz/2.4GHz ISM Radios
●Cellular/PCS Handsets
●GPS Receivers
●Cordless Phones
●Wireless LANs
●Wireless Data
Features
●Wide Operating Frequency Range
MAX2640: 300MHz to 1500MHz
MAX2641: 1400MHz to 2500MHz
●Low Noise Figure
MAX2640: 0.9dB at 900MHz
MAX2641: 1.2dB at 1575MHz
1.3dB at 1900MHz
1.5dB at 2450MHz
●High Gain
MAX2640: 15.1dB at 900MHz
MAX2641: 15.7dB at 1575MHz
14.4dB at 1900MHz
13.5dB at 2450MHz
●High Reverse Isolation
MAX2640: 40dB at 900MHz
MAX2641: 31dB at 1575MHz
30dB at 1900MHz
24dB at 2450MHz
●+2.7V to +5.5V Single-Supply Operation
●Low 3.5mA Supply Current
●Ultra-Small SOT23-6 Package
19-1384; Rev 4; 2/15
Pin Configuration appears at end of data sheet.
+Denotes a lead(Pb)-free/RoHS-compliant package.
T = Tape and reel.
PART TEMP
RANGE
PIN-
PACKAGE
SOFT
TOP MARK
MAX2640EUT-T -40°C to +85°C 6 SOT23 AAAV
MAX2640EUT+T -40°C to +85°C 6 SOT23 AAAV
MAX2640AUT+T -40°C to +125°C 6 SOT23 AAAV
MAX2641EUT-T -40°C to +85°C 6 SOT23 AAAW
MAX2641EUT+T -40°C to +125°C 6 SOT23 AAAW
Ordering Information
C3
C4
Z1
RFIN
C1
VCC
VCC
RFIN C2
ZM1
BIAS GENERATOR
GND
LNA RF OUT
RF OUT
MAX2640
MAX2641
ZM2
*The series inductor Z1 can be replaced by a transmission line of appropriate impedance
and electrical length.
FREQUENCY (MHz) C1
VALUE
(pF)
C2
VALUE
(pF)
C3
VALUE
(pF)
C4
VALUE
(pF)
Z1*
VALUE
(nH)
ZM1
VALUE
(pF)
ZM2
VALUE
MAX2640 MAX2641
900
—
—
—
—
1575
1900
2450
470
100
470
470
3
100
100
100
470
470
470
470
—
—
—
100
9.85
5.6
2.55
1.65
2
1
1
1
—
6.8nH
1pF
1pF
MAX2640/MAX2641 300MHz to 2500MHz SiGe
Ultra-Low-Noise Amplifiers
Typical Operating Circuit
EVALUATION KIT AVAILABLE
VCC to GND ...........................................................-0.3V to +6V
RFIN Power (50Ω source) (Note 1) .................................+5dBm
Continuous Power Dissipation (TA = +70°C)
SOT23-6 (derate 8.7mW/°C above +70°C) .................696mW
Operating Temperature Range
MAX2640EUT/MAX2641EUT ............................. -40°C to +85°C
MAX2640AUT ................................................... -40°C to +125°C
Storage Temperature Range ............................ -65°C to +160°C
Lead Temperature (soldering, 10s) .................................+300°C
(VCC = +3.0V, PRFIN = -34dBm, ZO = 50Ω, TA = +25°C, unless otherwise noted.) (Notes 2 and 3)
(VCC = +2.7V to +5.5V, TA = -40°C to +85°C (MAX2640EUT/MAX2641EUT), TA = -40°C to +125°C (MAX2640AUT), unless otherwise
noted. Typical values are at VCC = +3.0V, TA = +25°C.) Limits at TA = +25°C are guaranteed by production test. Limits over temperature
are guaranteed by design and characterization.
PARAMETER CONDITIONS MIN TYP MAX UNITS
MAX2640 (fRFIN = 900MHz)
RFIN Frequency Range 300 1500 MHz
Gain 12.8 15.1 dB
Gain Variation Over Temperature TA = -40°C to +85°C (MAX2640EUT) 0.6 1.7 dB
TA = -40°C to +125°C (MAX2640AUT) 0.9 2.5
Noise Figure (Note 4) 0.9 1.1 dB
Input Return Loss -11 dB
Output Return Loss -14 dB
Reverse Isolation 40 dB
Input 1dB Gain Compression Point -22 dBm
Input Third-Order Intercept Point (Note 5) -10 dBm
MAX2641 (fRFIN = 1900MHz)
RFIN Frequency Range 1400 2500 MHz
Gain 12.4 14.4 dB
Gain Variation Over Temperature TA = TMIN to TMAX 0.9 2.4 dB
Noise Figure (Note 4) 1.3 1.5 dB
Input Return Loss -12 dB
Output Return Loss -12 dB
Reverse Isolation 30 dB
Input 1dB Gain Compression Point -21 dBm
Input Third-Order Intercept Point (Note 6) -4 dBm
PARAMETER CONDITIONS MIN TYP MAX UNITS
Operating Supply Voltage 2.7 5.5 V
Operating Supply Current
TA = +25°C 3.5 4.7
mA
TA = -40°C to +85°C
(MAX2640EUT/MAX2641EUT) 6.4
TA = -40°C to +125°C (MAX2640AUT) 7.8
CAUTION! ESD SENSITIVE DEVICE
MAX2640/MAX2641 300MHz to 2500MHz SiGe
Ultra-Low-Noise Ampliers
www.maximintegrated.com Maxim Integrated
│
2
RF Electrical Characteristics
DC Electrical Characteristics
Note 1: Pin must be AC-coupled with a DC blocking capacitor.
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.
Absolute Maximum Ratings
(VCC = +3V, PRFIN = -34dBm, Typical Operating Circuit, TA = +25°C, unless otherwise noted.)
Note 2: Guaranteed by design and characterization.
Note 3: Measured using typical operating circuit. Input and output impedance matching networks were optimized for best simulta-
neous gain and noise-figure performance.
Note 4: External component and circuit losses degrade noise-figure performance. Specification excludes external component and
circuit board losses.
Note 5: Measured with two input tones, f1 = 899MHz, f2 = 901MHz, both at -34dBm per tone.
Note 6: Measured with two input tones, f1 = 1899MHz, f2 = 1901MHz, both at -34dBm per tone.
Note 7: Measured with two input tones, f1 = 1574MHz, f2 = 1576MHz, both at -34dBm per tone.
Note 8: Measured with two input tones, f1 = 2449MHz, f2 = 2451MHz, both at -34dBm per tone.
(VCC = +3.0V, PRFIN = -34dBm, ZO = 50Ω, TA = +25°C, unless otherwise noted.) (Notes 2 and 3)
PARAMETER CONDITIONS MIN TYP MAX UNITS
MAX2641 (fRFIN = 1575MHz)
Gain 15.7 dB
Noise Figure (Note 4) 1.2 dB
Input Return Loss -8 dB
Output Return Loss -15 dB
Reverse Isolation -31 dB
Input 1dB Gain Compression Point -21 dBm
Input Third-Order Intercept Point (Note 7) +1.4 dBm
MAX2641 (fRFIN = 2450MHz)
Gain 13.5 dB
Noise Figure (Note 4) 1.5 dB
Input Return Loss -10 dB
Output Return Loss -11 dB
Reverse Isolation -24 dB
Input 1dB Gain Compression Point -19 dBm
Input Third-Order Intercept Point (Note 8) -2.5 dBm
0
1
2
3
800 880840 920 960 1000
MAX2640 MATCHED AT 900MHz
NOISE FIGURE vs. FREQUENCY
MAX2640-03
FREQUENCY (MHz)
NOISE FIGURE (dB)
TA = +85°C
TA = +25°C
TA = -40°C
12
13
15
14
16
800 840 880 920 960 1000
MAX2640 MATCHED AT 900MHz
GAIN vs. FREQUENCY
MAX2640-01
FREQUENCY (MHz)
GAIN (dB)
TA = -40°C
TA = +25°C
TA = +85°C
0
2
1
4
3
5
6
2 43 5 6
MAX2640
SUPPLY CURRENT vs. SUPPLY VOLTAGE
MAX2640-01
VCC (V)
ICC (mA)
TA = +85°C
TA = +25°C
TA = -40°C
MAX2640/MAX2641 300MHz to 2500MHz SiGe
Ultra-Low-Noise Ampliers
www.maximintegrated.com Maxim Integrated
│
3
Typical Operating Characteristics
RF Electrical Characteristics (continued)
(VCC = +3V, PRFIN = -34dBm, Typical Operating Circuit, TA = +25°C, unless otherwise noted.)
-60
-30
-40
-50
-20
-10
0
1800 18801840 1920 1960 2000
MAX2641 MATCHED AT 1900MHz
REVERSE ISOLATION vs. FREQUENCY
MAX2640-10
FREQUENCY (MHz)
REVERSE ISOLATION (dB)
-16
-13
-14
-15
-12
-11
-10
-9
-8
-7
-6
1800 1850 1900 1950 2000
MAX2641 MATCHED AT 1900MHz
INPUT RETURN LOSS AND
OUTPUT RETURN LOSS vs. FREQUENCY
MAX2640-09
FREQUENCY (MHz)
RETURN LOSS (dB)
INPUT RETURN LOSS
OUTPUT RETURN LOSS
0
1
2
3
1800 18801840 1920 1960 2000
MAX2641 MATCHED AT 1900MHz
NOISE FIGURE vs. FREQUENCY
MAX2640-08
FREQUENCY (MHz)
NOISE FIGURE (dB)
TA = +85°C
TA = +25°C
TA = -40°C
12
13
15
14
16
1800 1840 1880 1920 1960 2000
MAX2641 MATCHED AT 1900MHz
GAIN vs. FREQUENCY
MAX2640-07
FREQUENCY (MHz)
GAIN (dB)
TA = -40°C
TA = +25°C
TA = +85°C
0
2
1
4
3
5
6
2 43 5 6
MAX2641
SUPPLY CURRENT vs. SUPPLY VOLTAGE
MAX2640-06
V
CC
(V)
ICC (mA)
TA = +85°C
TA = +25°C
TA = -40°C
-60
-30
-40
-50
-20
-10
0
800 880840 920 960 1000
MAX2640 MATCHED AT 900MHz
REVERSE ISOLATION vs. FREQUENCY
MAX2640-05
FREQUENCY (MHz)
REVERSE ISOLATION (dB)
-16
-13
-14
-15
-12
-11
-10
-9
-8
-7
-6
800 850 900 950 1000
MAX2640 MATCHED AT 900MHz
INPUT RETURN LOSS AND
OUTPUT RETURN LOSS vs. FREQUENCY
MAX2640-04
FREQUENCY (MHz)
RETURN LOSS (dB)
INPUT RETURN LOSS
OUTPUT RETURN LOSS
MAX2640/MAX2641 300MHz to 2500MHz SiGe
Ultra-Low-Noise Ampliers
Maxim Integrated
│
4
www.maximintegrated.com
Typical Operating Characteristics (continued)
Detailed Description
The MAX2640 and MAX2641 are ultra-low-noise ampli-
fiers that operate with RF input frequency ranges
of 300MHz to 1500MHz (MAX2640) or 1400MHz to
2500MHz (MAX2641). These devices are available in
SOT23-6 packages and contain internal bias circuitry to
minimize the number of required external components.
Their small size and low external component count make
them ideal for applications where board space is limited.
Applications Information
External Matching Components
The MAX2640/MAX2641 are easy to use, generally
requiring only five external components as shown in
the Typical Operating Circuit. To reduce external com-
ponent count further, replace external inductors with
microstrip transmission lines. The high reverse isola-
tion allows the tuning of the input matching network
without affecting the output match, and vice versa.
Select input and output matching networks to obtain the
desired combination of gain, noise figure, and return
loss performance. The Typical Operating Circuit show
the recommended input and output matching networks
for the MAX2640/MAX2641 at 900MHz and 1900MHz,
respectively. These values are optimized for best
simultaneous gain, noise figure, and return loss per-
formance. To aid in the design of matching networks
for other frequencies, Tables 1 and 2 list typical device
S-parameters and Tables 3 and 4 list typical device noise
parameters.
Pin Description
IN NAME FUNCTION
1 RFIN Amplifier Input. AC-couple to this pin with a DC blocking capacitor. Use recommended input matching
network (see Typical Operating Circuit).
2, 3, 5 GND Ground. For optimum performance, provide a low inductance connection to the ground plane.
4 RFOUT Amplifier Output. Use the recommended series blocking or matching capacitor (see Typical Operating Circuit).
6 VCC
Supply Voltage. Bypass to ground directly at the supply pin. The value of the bypass capacitor is determined by
the lowest operating frequency. Additional bypassing may be necessary for long VCC lines (see Typical Operating
Circuit).
MAX2640/MAX2641 300MHz to 2500MHz SiGe
Ultra-Low-Noise Ampliers
www.maximintegrated.com Maxim Integrated
│
5
Table 2. MAX2641 Typical Scattering Parameters at VCC = +3V, TA = +25°C
Table 1. MAX2640 Typical Scattering Parameters at VCC = +3V, TA = +25°C
FREQUENCY
(MHz)
S11
MAG PHASE S21
MAG PHASE S12
MAG PHASE S22
MAG PHASE
400 0.907 -35.1 4.62 109.1 0.001 13.5 0.302 108.4
500 0.882 -43.1 4.70 90.4 0.001 64.7 0.33 93.6
600 0.858 -50.8 4.76 70.7 0.001 55.2 0.352 81.5
700 0.832 -58.1 4.80 50.6 0.002 39.4 0.365 69.4
800 0.810 -64.9 4.85 29.5 0.004 64.2 0.384 56.8
900 0.788 -71.0 4.77 9.2 0.005 36.3 0.396 44.7
1000 0.771 -76.6 4.74 -12.0 0.007 28.0 0.412 33.5
1100 0.749 -82.3 4.55 -32.4 0.010 12.3 0.436 21.9
1200 0.735 -88.0 4.48 -53.4 0.013 -10.6 0.455 10.7
1300 0.720 -93.4 4.24 -75.9 0.015 -28.2 0.469 -0.2
1400 0.702 -98.8 4.17 -94.9 0.021 -42.9 0.482 -9.9
1500 0.688 -104.9 3.81 -117.5 0.021 -59.8 0.489 -20.2
FREQUENCY
(MHz)
S11
MAG PHASE S21
MAG PHASE S12
MAG PHASE S22
MAG PHASE
1500 0.734 -75.5 4.397 -90.5 0.013 -80.3 0.535 17.7
1600 0.717 -80.3 4.209 -109.8 0.016 -91.9 0.514 8.6
1700 0.695 -85.3 4.193 -131.6 0.018 -116.5 0.513 -0.5
1800 0.678 -90.6 3.876 -150.0 0.021 -128.7 0.510 -10.6
1900 0.661 -96.6 3.801 -173.5 0.023 -150.6 0.493 -21.6
2000 0.646 -102.6 3.456 166.9 0.026 -166.6 0.470 -32.0
2100 0.632 -108.8 3.302 146.4 0.028 171.7 0.431 -43.4
2200 0.620 -114.0 2.981 123.6 0.029 150.7 0.403 -56.1
2300 0.610 -119.4 2.781 105.3 0.033 132.2 0.374 -69.4
2400 0.604 -124.6 2.430 82.9 0.032 111.2 0.338 -86.2
2500 0.603 -128.4 2.118 64.7 0.030 95.7 0.316 -98.3
MAX2640/MAX2641 300MHz to 2500MHz SiGe
Ultra-Low-Noise Ampliers
www.maximintegrated.com Maxim Integrated
│
6
Layout and Power-Supply Bypassing
A properly designed PCB is essential to any RF/micro-
wave circuit. Be sure to use controlled impedance lines
on all high-frequency inputs and outputs. The power
supply should be bypassed with decoupling capacitors
located close to the device VCC pins. For long VCC lines,
it may be necessary to add additional decoupling capac-
itors. These additional capacitors can be located further
away from the device package.
Proper grounding of the GND pins is essential. If the
PCB uses a topside RF ground, connect it directly to all
GND pins. For a board where the ground plane is not on
the component side, the best technique is to connect the
GND pin to the board with a plated through-hole close to
the package.
Table 4. MAX2641 Typical Noise Parameters at VCC = +3V, TA = +25°C
Table 3. MAX2640 Typical Noise Parameters at VCC = +3V, TA = +25°C
FREQUENCY (MHz) fMIN (dB) |Γ opt| Γ opt ANGLE RN (Ω)
400 0.66 0.56 21 12.5
500 0.69 0.54 25 11.9
600 0.72 0.51 30 11.3
700 0.75 0.48 35 10.8
800 0.78 0.46 40 10.2
900 0.82 0.43 45 9.7
1000 0.85 0.40 50 9.3
1100 0.89 0.37 56 8.8
1200 0.93 0.35 62 8.3
1300 0.97 0.32 68 7.9
1400 1.01 0.29 77 7.4
1500 0.26 84 7.0
FREQUENCY (MHz) fMIN (dB) |Γ opt| Γ opt ANGLE RN (Ω)
1500 1.02 0.43 44 12.4
1600 1.05 0.40 47 11.8
1700 1.08 0.38 50 11.3
1800 1.10 0.36 54 10.8
1900 1.14 0.32 58 10.3
2000 1.17 0.30 62 9.9
2100 1.20 0.28 66 9.4
2200 1.23 0.25 71 9.0
2300 1.27 0.22 77 8.6
2300 1.30 0.19 82 8.3
2500 1.34 0.17 91 8.0
MAX2640/MAX2641 300MHz to 2500MHz SiGe
Ultra-Low-Noise Ampliers
www.maximintegrated.com Maxim Integrated
│
7
GND
RFOUTGND
16VCC
5 GND
RFIN
MAX2640
MAX2641
SOT23-6
TOP VIEW
2
34
+
MAX2640/MAX2641 300MHz to 2500MHz SiGe
Ultra-Low-Noise Ampliers
www.maximintegrated.com Maxim Integrated
│
8
Package Information
For the latest package outline information and land patterns (footprints), go to www.maximintegrated.com/packages. Note that a “+”,
“#”, or “-” in the package code indicates RoHS status only. Package drawings may show a different suffix character, but the drawing
pertains to the package regardless of RoHS status.
Pin Conguration
PACKAGE TYPE PACKAGE CODE DOCUMENT NO. LAND PATTERN NO.
6 SOT23 U6+4 21-0058 90-0175
Maxim Integrated cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim Integrated product. No circuit patent licenses
are implied. Maxim Integrated reserves the right to change the circuitry and specications without notice at any time. The parametric values (min and max limits)
shown in the Electrical Characteristics table are guaranteed. Other parametric values quoted in this data sheet are provided for guidance.
Maxim Integrated and the Maxim Integrated logo are trademarks of Maxim Integrated Products, Inc.
MAX2640/MAX2641 300MHz to 2500MHz SiGe
Ultra-Low-Noise Ampliers
© 2015 Maxim Integrated Products, Inc.
│
9
Revision History
REVISION
NUMBER
REVISION
DATE DESCRIPTION PAGES
CHANGED
0 10/98 Initial release —
1 2/99 Initial release of evaluation kit, added to data sheet —
2 8/03 Informed customers of ESD sensitive devices —
3 4/07 Added automotive temperature range 1, 2, 5
4 2/15 Removed automotive reference from data sheet 1
For pricing, delivery, and ordering information, please contact Maxim Direct at 1-888-629-4642, or visit Maxim Integrated’s website at www.maximintegrated.com.