19-1894; Rev 1; 8/03
KIT
ATION
EVALU
BLE
AVAILA
5GHz to 6GHz Low-Noise Amplifier
in 6-Pin UCSP
Features
o
5GHz to 6GHz Wideband Operation
o
Low Noise Figure: 1.8dB at 5.25GHz
o
High Gain: 17dB
o
High IIP3: 0dBm
o
+2.7V to +3.6V Single-Supply Operation
o
Chip-Scale Package (UCSP) Measuring
1.0mm
✕
1.5mm
General Description
The MAX2648 high-linearity, silicon-germanium (SiGe)
low-noise amplifier (LNA) is designed for 5GHz wireless
LAN systems based on IEEE 802.11a and HiperLAN2
standards. The LNA provides high gain, low noise, and
high linearity performance, allowing it to be used as a
first-stage LNA, an LO buffer, or a transmitter driver
amplifier. This highly versatile amplifier provides 17dB
gain, 1.8dB noise figure, and 0dBm input third-order
intercept point (IIP3) while consuming only 12mA.
The MAX2648 is designed on a low-noise, advanced
SiGe process optimized for high-frequency applica-
tions. It operates over a +2.7V to +3.6V supply range.
The device is packaged in a tiny 2
✕
3 chipscale pack-
age (UCSP™) with six solder bumps, measuring 1.0mm
✕
1.5mm.
MAX2648
Ordering Information
PART
MAX2648EBT-T
TEMP RANGE
-40°C to +85°C
PIN-PACKAGE
2
✕
3 UCSP
Pin Configuration
Applications
IEEE 802.11a Wireless LAN
ETSI HiperLAN/2
5GHz ISM
Microwave Radios
RFOUT
B3
GND
B2
A2
GND
V
CC
B1
BIAS
A1
RFIN
MAX2648
A3
GND
2 x 3 UCSP
UCSP is a trademark of Maxim Integrated Products, Inc.
TOP VIEW
(BUMPS ON BOTTOM OF DIE)
Typical Application Circuit
RF INPUT
C1
100pF
WIDTH = 21 mils
LENGTH = 300 mils**
OPERATING BAND
5150MHz TO 5350MHz
C8*
A1
RFIN
A2
GND
A3
GND
5725MHz TO 5825MHz
C7*
1.0pF
0.7pF
C8*
0.9pF
0.8pF
*THESE ARE ATC 500-SERIES, LOW-LOSS
PORCELAIN 0603 CAPACITORS.
**REFER TO MAX2648 EV KIT DATA SHEET FOR
MORE LAYOUT INFORMATION.
MAX2648
C2
100pF
V
CC
B1
GND
B2
RFOUT
B3 WIDTH = 21 mils
LENGTH = 300 mils**
C7*
L1
22nH
C6
100pF
RF
OUTPUT
C3
1000pF
V
CC
R2
8.2Ω
C4
0.01µF
________________________________________________________________
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.
5GHz to 6GHz Low-Noise Amplifier
in 6-Pin UCSP
MAX2648
ABSOLUTE MAXIMUM RATINGS
V
CC
to GND ...........................................................-0.3V to +6.0V
RFOUT to GND......................................................-0.3V to +6.0V
RFIN.......................................................................-0.3V to +0.8V
RFIN Power (50Ω source) ..............................................+15dBm
Continuous Power Dissipation
2
✕
3-Bump UCSP (derate 24mW/°C above +70°C) ....500mW
Operating Temperature Range ...........................-40°C to +85°C
Junction Temperature .....................................................+150°C
Storage Temperature Range .............................-55°C to +150°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.
CAUTION!
ESD SENSITIVE DEVICE
DC ELECTRICAL CHARACTERISTICS
(V
CC
= +2.7V to +3.6V, no RF signals applied, RFIN and RFOUT terminated in 50Ω through a DC-blocking capacitor, RFOUT con-
nected to V
CC
. Typical values for V
CC
= +3.0V, T
A
= +25°C, unless otherwise noted.)
PARAMETER
Supply Voltage Range
Supply Current
SYMBOL
V
CC
I
CC
T
A
= +25°C
T
A
= -40°C to +85°C (Note 1)
CONDITIONS
MIN
2.7
12.3
TYP
MAX
3.6
15
18
UNITS
V
mA
Note 1:
Limits are guaranteed by design and characterization, and are not production tested.
AC ELECTRICAL CHARACTERISTICS
(MAX2648 evaluation kit, V
CC
= +3.0V, f
IN
= 5250MHz, P
IN
= -30dBm, 50Ω system, T
A
= +25°C. Typical values for V
CC
= +3.0V,
T
A
= +25°C, unless otherwise noted. All limits are guaranteed by design and characterization and are not production tested.)
PARAMETER
Frequency Range
Power Gain
Maximum Gain Variation over
Temperature
Input Third Order Intercept
Noise Figure
Input Return Loss
Output Return Loss
Reverse Isolation
IIP3
NF
|S
11
|
|S
22
|
|S
12
|
SYMBOL
f
IN
|S
21
|
(Note 2)
(Note 3)
T
A
= -40°C to +85°C
Two tones at 5250MHz and 5251MHz,
-30dBm per tone (Note 4)
(Note 4)
-4.0
16
CONDITIONS
MIN
TYP
5250
17.4
0.2
0
1.8
-14
-14
-31
2.3
1.0
MAX
UNITS
MHz
dB
dB
dBm
dB
dB
dB
dB
Note 2:
The recommended operating range is 5100MHz to 5850MHz. Operation outside this frequency range is possible but has not
been characterized. The device is matched, characterized, and tested at 5250MHz. For optimum performance at a given
frequency, the input and output ports must be properly matched. See
Applications Information
section for more information
on matching.
Note 3:
Specifications are corrected for board losses (0.4dB at input, 0.4dB at output)
Note 4:
Specification is corrected for board losses (0.4dB at input)
2
_______________________________________________________________________________________
5GHz to 6GHz Low-Noise Amplifier
in 6-Pin UCSP
Typical Operating Characteristics
(MAX2648 evaluation kit tuned for 5150MHz to 5350MHz, V
CC
= +3.0V, f
IN
= 5250MHz, P
IN
= -30dBm, 50Ω system, T
A
= +25°C,
unless otherwise noted.)
SUPPLY CURRENT
vs. SUPPLY VOLTAGE
MAX2648 toc01
MAX2648
GAIN vs. TEMPERATURE
MAX2648 toc02
GAIN vs. SUPPLY VOLTAGE
18.0
17.8
17.6
GAIN (dB)
17.4
17.2
17.0
16.8
16.6
16.4
16.2
MAX2648 toc03
20
18
16
SUPPLY CURRENT (mA)
14
T
A
= +85°C
18.4
18.2
18.0
17.8
GAIN (dB)
17.6
17.4
17.2
17.0
18.2
12
10
8
6
4
2
0
2.7 2.8 2.9 3.0 3.1 3.2 3.3 3.4 3.5 3.6
SUPPLY VOLTAGE (V)
T
A
= -40°C
T
A
= +25°C
16.8
16.6
16.4
-40 -30 -20 -10 0 10 20 30 40 50 60 70 80 90
TEMPERATURE (°C)
2.7 2.8 2.9 3.0 3.1 3.2 3.3 3.4 3.5 3.6
SUPPLY VOLTAGE (V)
P(1dB) vs. SUPPLY VOLTAGE
MAX2648 toc04
IIP3 vs. SUPPLY VOLTAGE
INPUT 3rd-ORDER INTERCEPT (dBm)
0.8
0.6
0.4
0.2
0
-0.2
-0.4
-0.6
-0.8
-1.0
MAX2648 toc05
IIP3 vs. TEMPERATURE
1.5
1.0
0.5
0
-0.5
-1.0
-1.5
MAX2648 toc06
7.0
OUTPUT 1dB DOWN POINT (dBm)
6.8
6.6
6.4
6.2
6.0
5.8
5.6
5.4
1.0
INPUT 3rd-ORDER INTERCEPT (dBm)
2.0
2.7 2.8 2.9 3.0 3.1 3.2 3.3 3.4 3.5 3.6
SUPPLY VOLTAGE (V)
2.7 2.8 2.9 3.0 3.1 3.2 3.3 3.4 3.5 3.6
SUPPLY VOLTAGE (V)
-2.0
-40 -30 -20 -10 0 10 20 30 40 50 60 70 80 90
TEMPERATURE (°C)
|S
11
|, |S
12
|, AND |S
22
| vs. FREQUENCY
(5250MHz APPLICATION CIRCUIT)
MAX2648 toc07
|S
21
| vs. FREQUENCY
(5250MHz APPLICATION CIRCUIT)
MAX2648 toc08
NOISE FIGURE vs. FREQUENCY
(5250MHz APPLICATION CIRCUIT)
MAX2648 toc09
0
-5
-10
MAGNITUDE (dB)
|S
22
|
19
18
17
3.0
2.5
NOISE FIGURE (dB)
2.0
1.5
1.0
0.5
0
-20
-25
-30
-35
-40
5000
5200
5400
5600
5800
6000
OPERATING FREQUENCY (MHz)
|S
11
|
|S
12
|
|S
21
| (dB)
-15
16
15
14
13
12
11
5000
5200
5400
5600
5800
6000
OPERATING FREQUENCY (MHz)
5150 5175 5200 5225 5250 5275 5300 5325 5350
OPERATING FREQUENCY (MHz)
_______________________________________________________________________________________
3
5GHz to 6GHz Low-Noise Amplifier
in 6-Pin UCSP
MAX2648
Typical Operating Characteristics (continued)
(MAX2648 evaluation kit tuned for 5150MHz to 5350MHz, V
CC
= +3.0V, f
IN
= 5250MHz, P
IN
= -30dBm, 50Ω system, T
A
= +25°C,
unless otherwise noted.)
NOISE FIGURE vs. TEMPERATURE
(5250MHz APPLICATION CIRCUIT)
MAX2648 toc10
|S
11
|, |S
12
|, AND |S
22
| vs. FREQUENCY
(5800MHz APPLICATION CIRCUIT)
-5
-10
MAX2648 toc11
3.0
2.5
NOISE FIGURE (dB)
2.0
1.5
1.0
0.5
0
0
|S
11
|
MAGNITUDE (dB)
-15
-20
-25
-30
-35
-40
5000
5200
5400
5600
5800
6000
|S
22
|
|S
12
|
-40 -30 -20 -10 0 10 20 30 40 50 60 70 80 90
OPERATING FREQUENCY (MHz)
OPERATING FREQUENCY (MHz)
|S
21
| vs. FREQUENCY
(5800MHz APPLICATION CIRCUIT)
MAX2648 toc12
NOISE FIGURE vs. FREQUENCY
(5800MHz APPLICATION CIRCUIT)
MAX2648 toc13
18
17
16
|S
21
| (dB)
15
14
13
12
11
10
5000
5200
5400
5600
5800
3.0
2.5
NOISE FIGURE (dB)
2.0
1.5
1.0
0.5
0
5725
5750
5775
5800
6000
5825
OPERATING FREQUENCY (MHz)
OPERATING FREQUENCY (MHz)
Pin Description
PIN
A1
A2, A3, B2
B3
B1
NAME
RFIN
GND
RFOUT
V
CC
FUNCTION
Amplifier Input. AC-couple to this pin with a DC-blocking capacitor. External matching network is
required for optimum performance.
Ground. Provide a low-inductance connection to the ground plane.
Amplifier Output. Provide DC bias to V
CC
through an RF choke or a quarter-wave transmission line
(see evaluation kit layout). External matching network is required for optimum performance.
Power-Supply Input. Bypass directly to ground plane at this bump. Additional bypassing may be
necessary for long V
CC
lines.
4
_______________________________________________________________________________________
5GHz to 6GHz Low-Noise Amplifier
in 6-Pin UCSP
Detailed Description
The MAX2648 low-noise amplifier offers high gain, high
linearity, and low-noise performance from 5GHz to
6GHz. This LNA also functions as a PA predriver or an
LO buffer. The device has been fully characterized and
tested in the 5.2GHz and 5.8GHz bands.
If area allows, a better way to supply a bias for narrow-
band operation is to design in a quarter-wave transmis-
sion line. The far side of this high-Z
0
transmission line is
AC-shorted to ground with a radial stub; low-frequency
decoupling is handled by a 1000pF shunt capacitor to
ground nearby. Bias this point through an RF choke,
and decouple the supply with a few µF at the V
CC
con-
nection.
MAX2648
Applications Information
Optimal gain and noise figure performance requires
input and output matching circuits tuned for the band
of interest. All electrical specifications and typical oper-
ating characteristics are measured on the MAX2648
evaluation kit (EV kit), which is tuned for operation in
the 5.2GHz band. Referencing the application circuit,
PC board layout, and components specified in the
MAX2648 EV kit data sheet will reduce evaluation and
design time for 5.2GHz ISM-band system designs. For
applications in other bands, refer to the MAX2648 [S]-
parameters (Table 1), noise parameters (Table 2), and
comments below to aid design.
Power-Supply Bypassing
Proper power-supply bypassing is essential for high-
frequency circuit stability. Place a small value capacitor
as close to the IC as possible to decouple high-fre-
quency noise. Place a larger value capacitor near the
supply to decouple low-frequency noise. Whenever
possible, place the ground-connected side of bypass
capacitors within a few millimeters of the IC’s ground
connections.
Layout Considerations
A properly designed PC board is an essential part of
any RF/microwave circuit. Keep RF signal lines as short
as possible to reduce losses, EMI, and stray induc-
tance. Use multiple separate low-inductance-plated
vias to the ground plane for each ground bump.
The chip-scale package (UCSP) has a bump pitch of
0.5mm (19.7mil) and a bump diameter of 0.3mm
(12mil). Therefore, lay out the solder pad spacing on
0.5mm (19.7mil) centers, and use a pad size of
0.25mm (10mil) and a solder mask opening of 0.33mm
(13mil). Round or square pads are permissible. Refer to
the Maxim application note,
Wafer Level Ultra-Chip-
Scale Packaging,
for additional detailed information on
UCSP layout and handling.
Input Matching
The input stage is internally biased, so no external bias
circuitry is required at RFIN. Be sure to AC-couple to
the input.
Since the noise figure of the LNA design is severely
degraded by low-Q matching components, always
design with high-Q wire-wound inductors and low-loss
capacitors. Remember that package parasitics must be
taken into consideration; always use components with
self-resonant frequencies higher than the intended fre-
quency of operation.
Output Matching
The output of the MAX2648 is an open-collector transis-
tor; the DC bias and RF matching network are off-chip
as illustrated in the
Typical Application Circuit.
Bias the
output stage with V
CC
through an RF choke, leaving as
little pad exposed as possible—any exposed pad here
will act like a small tuning stub and contribute a small,
low-Q, shunt capacitor to the matching network.
Chip Information
TRANSISTOR COUNT: 85
_______________________________________________________________________________________
5
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