MAX2659 MAXIM [Maxim Integrated Products], MAX2659 Datasheet - Page 5

• Manufacturer Part Number: MAX2659
• Description: GPS/GNSS Low-Noise Amplifier
• Manufacturer: MAXIM [Maxim Integrated Products]

Table 1. Typical S11 Values
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
while providing a IP
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.
FREQUENCY (MHz)
PIN
1, 2
3
4
5
6
1000
1100
1200
1300
1400
1500
1575
1600
1700
1800
1900
2000
RFOUT
NAME
SHDN
RFIN
GND
V
CC
_______________________________________________________________________________________
1dB
Input and Output Matching
Detailed Description
Ground. Connect to the PCB ground plane.
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.
RF Output. RFOUT is internally matched to 50
of -12dBm and an IIP3 of -5dBm.
REAL S11
-0.676
-0.228
-0.58
-0.68
-0.74
-0.74
-0.56
-0.47
-0.44
-0.36
-0.14
-0.3
IMAGINARY S11
GPS/GNSS Low-Noise Amplifier
-j0.356
j0.036
j0.415
j0.467
j0.567
j0.622
-j0.52
-j0.16
j0.22
j0.36
j0.43
j0.51
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.
A properly designed PC board (PCB) is essential to any
RF microwave circuit. Use controlled-impedance lines
on all high-frequency inputs and outputs. Bypass V
with decoupling capacitors located close to the device.
For long V
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.
PROCESS: SiGe BiCMOS
FUNCTION
and incorporates an internal DC-blocking capacitor.
CC
lines, it may be necessary to add decou-
Applications Information
Chip Information
Pin Description
Shutdown
CC
5