GPS/GNSS Low-Noise Amplifier
MAX2659
Pin Description
PIN
1, 2
3
NAME
GND
FUNCTION
Ground. Connect to the PCB ground plane.
RFIN
RF Input. Requires a DC-blocking capacitor and external matching components.
Supply Voltage. Bypass to ground with a 33nF capacitor as close as possible to the IC.
Shutdown Input. A logic-low disables the device.
4
V
CC
5
SHDN
6
RFOUT
RF Output. RFOUT is internally matched to 50ꢀ and incorporates an internal DC-blocking capacitor.
Shutdown
Detailed Description
The MAX2659 includes a shutdown feature to turn off
the entire chip. Apply a logic high to SHDN pin to place
the part in the active mode and a logic low to place the
part in the shutdown mode.
The MAX2659 is an LNA designed for GPS L1,
GALILEO, and GLONASS applications. The device fea-
tures a power-shutdown control mode to eliminate the
need for an external supply switch. The device
achieves a 20.5dB gain and an ultra-low-noise figure of
0.8dB. The MAX2659 consumes approximately 4.1mA
Applications Information
A properly designed PC board (PCB) is essential to any
RF microwave circuit. Use controlled-impedance lines
while providing a IP
of -12dBm and an IIP3 of -5dBm.
1dB
on all high-frequency inputs and outputs. Bypass V
CC
Input and Output Matching
with decoupling capacitors located close to the device.
For long V lines, it may be necessary to add decou-
The MAX2659 requires an off-chip input matching. Only
a 6.8nH inductor in series with a DC-blocking capacitor
is needed to form the input matching circuit. The
Typical Application Circuit diagram shows the recom-
mended input-matching network. These values are
optimized for the best simultaneous gain, noise figure,
and return loss performance. Table 1 lists typical
device S11 values. The MAX2659 integrates an on-chip
output matching to 50Ω at the output, eliminating the
need for external matching components.
CC
pling capacitors. Locate these additional capacitors
further away from the device package. Proper ground-
ing of the GND pins is essential. If the PCB uses a top-
side RF ground, connect it directly to the GND pins. For
a board where the ground is not on the component
layer, connect the GND pins to the board with multiple
vias close to the package.
Table 1. Typical S11 Values
Chip Information
FREQUENCY (MHz)
REAL S11
-0.58
IMAGINARY S11
-j0.52
PROCESS: SiGe BiCMOS
1000
1100
1200
1300
1400
1500
1575
1600
1700
1800
1900
2000
-0.68
-j0.356
-j0.16
-0.74
-0.74
j0.036
j0.22
Package Information
-0.676
-0.56
For the latest package outline information and land patterns
(footprints), go to www.maxim-ic.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.
j0.36
-0.47
j0.415
j0.43
-0.44
-0.36
j0.467
j0.51
PACKAGE
TYPE
PACKAGE
CODE
OUTLINE
NO.
LAND
PATTERN NO.
-0.3
-0.228
-0.14
j0.567
j0.622
6 µDFN
L611+2
21-0147
90-0084
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5