Maximum Current into RF Input .........................................10mA
Operating Temperature Range .......................... -40°C to +85°C
Junction Temperature .....................................................+150°C
Storage Temperature Range............................ -65°C to +160°C
Lead Temperature (soldering, 10s) ........ Reflow Profile (Note 1)
Soldering Temperature (reflow) ......................................+260°C
Note 1:
Refer to Application Note 1891:
Wafer-Level Packaging (WLP) and Its Applications.
CAUTION!
ESD SENSITIVE DEVICE
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
(MAX2686/MAX2688 EV kit, V
CC
= 1.6V to 3.3V, T
A
= -40NC to +85NC, no RF signals are applied. Typical values are at V
CC
= 2.85V
and T
A
= +25NC, unless otherwise noted.) (Note 2)
PARAMETER
Supply Voltage
Supply Current
Digital Input Logic-High
Digital Input Logic-Low
SHDN
= high
MAX2686
MAX2688
1.2
0.45
CONDITIONS
MIN
1.6
TYP
2.85
4.1
4.1
10
MAX
3.3
UNITS
V
mA
µA
V
V
Shutdown mode,
SHDN
= low
(Note 3)
(Note 3)
AC ELECTRICAL CHARACTERISTICS
(MAX2686/MAX2688 EV kit, V
CC
= 1.6V to 3.3V, T
A
= -40NC to +85NC, f
RFIN
= 1575.42MHz. Typical values are at V
CC
= 2.85V and
T
A
= +25NC, unless otherwise noted.) (Note 2)
PARAMETER
RF Frequency
L1 band
V
CC
= 2.85V (Note 4)
Power Gain
V
CC
= 1.6V
Noise Figure
In-Band 3rd-Order Input
Intercept Point
Out-of-Band 3rd-Order Input
Intercept Point
Input 1dB Compression Point
Input Return Loss
V
CC
= 1.6V to 3.3V
(Note 5)
(Note 6)
(Note 7)
MAX2686
MAX2688
MAX2686
MAX2688
MAX2686
MAX2688
MAX2686
MAX2688
MAX2686
MAX2688
MAX2686
MAX2688
14.7
11.9
14.4
11.6
CONDITIONS
MIN
TYP
1575.42
19
15.4
18.9
15.3
0.75
0.8
-3
+4
0
+7
-10
-6
8.5
dB
dBm
dBm
dBm
dB
dB
MAX
UNITS
MHz
2
GPS/GNSS Low-Noise Amplifiers
AC ELECTRICAL CHARACTERISTICS (continued)
(MAX2686/MAX2688 EV kit, V
CC
= 1.6V to 3.3V, T
A
= -40NC to +85NC, f
RFIN
= 1575.42MHz. Typical values are at V
CC
= 2.85V and
T
A
= +25NC, unless otherwise noted.) (Note 2)
PARAMETER
Output Return Loss
Reverse Isolation
CONDITIONS
MIN
TYP
15
40
MAX
UNITS
dB
dB
MAX2686/MAX2688
Note 2:
Min and max limits guaranteed by test at T
A
= +25°C and guaranteed by design and characterization at T
A
= -40°C and
T
A
= +85°C, unless otherwise noted.
Note 3:
Min and max limits guaranteed by test at T
A
= +25°C.
Note 4:
Min limit guaranteed by design and characterization.
Note 5:
Measured with the two tones located at 1MHz and 2MHz offset from the center of the GPS band with -27dBm/tone for the
MAX2686 and -24dBm/tone for the MAX2688.
Note 6:
Measured with input tones at 1713MHz (-27dBm) and 1851MHz (-39dBm).
Note 7:
Measured with a tone located at 5MHz offset from the center of the GPS band.
Typical Operating Characteristics
(MAX2686/MAX2688 EV kit. Typical values are at V
CC
= 2.85V, T
A
= +25°C, and f
RFIN
= 1575.42MHz, unless otherwise noted.)
INPUT RETURN LOSS vs. FREQUENCY
MAX2686 toc01
GAIN vs. FREQUENCY
MAX2686 toc02
REVERSE ISOLATION vs. FREQUENCY
-25
-30
-35
|S12| (dB)
-40
-45
-50
-55
-60
-65
-70
MAX2688
MAX2686
MAX2686 toc03
0
-5
-10
MAX2686
MAX2688
25
20
15
GAIN (dB)
10
MAX2686
-20
|S11| (dB)
-15
-20
-25
-30
-35
-40
500
1000
MAX2688
5
0
-5
1500
FREQUENCY (MHz)
2000
2500
500
1000
1500
FREQUENCY (MHz)
2000
2500
500
1000
1500
FREQUENCY (MHz)
2000
2500
OUTPUT RETURN LOSS vs. FREQUENCY
-5
-10
-15
-20
MAX2686
-25
-30
-35
500
1000
1500
FREQUENCY (MHz)
2000
2500
MAX2688
MAX2686 toc04
-1
-2
IIP3 (dBm)
-3
-4
-5
-6
1.6 1.8
2.0 2.2
2.4 2.6
2.8 3.0
3.2
SUPPLY VOLTAGE (V)
T
A
= -40°C
T
A
= +25°C
|S22| (dB)
T
A
= +85°C
MAX2686 toc05
0
(TWO TONES LOCATED AT 1MHz AND 2MHz OFFSET WITH -30dBm/TONE)
0
MAX2686 IN-BAND IIP3
vs. SUPPLY VOLTAGE AND TEMPERATURE
3
GPS/GNSS Low-Noise Amplifiers
MAX2686/MAX2688
Typical Operating Characteristics (continued)
(MAX2686/MAX2688 EV kit. Typical values are at V
CC
= 2.85V, T
A
= +25°C, and f
RFIN
= 1575.42MHz, unless otherwise noted.)
MAX2688 IN-BAND IIP3
vs. SUPPLY VOLTAGE AND TEMPERATURE
MAX2686 OUT-OF-BAND IIP3
vs. SUPPLY VOLTAGE AND TEMPERATURE
MAX2686 toc06
5
4
IIP3 (dBm)
T
A
= -40°C
T
A
= +25°C
1.5
1.0
0.5
IIP3 (dBm)
0
-0.5
-1.0
-1.5
-2.0
-2.5
-3.0
T
A
= +85°C
1.6 1.8
2.0 2.2
2.4 2.6
2.8 3.0
3.2
T
A
= -40°C
T
A
= +25°C
3
2
1
0
1.6 1.8
2.0 2.2
2.4 2.6
2.8 3.0
3.2
SUPPLY VOLTAGE (V)
T
A
= +85°C
SUPPLY VOLTAGE (V)
MAX2686 toc08
10
8
IIP3 (dBm)
6
4
2
0
T
A
= +25°C
T
A
= +85°C
-7
-8
INPUT P1dB (dBm)
-9
-10
-11
-12
-13
-14
-15
-16
T
A
= +85°C
T
A
= +25°C
T
A
= -40°C
T
A
= -40°C
1.6 1.8
2.0 2.2
2.4 2.6
2.8 3.0
3.2
1.6 1.8
2.0 2.2
2.4 2.6
2.8 3.0
3.2
SUPPLY VOLTAGE (V)
SUPPLY VOLTAGE (V)
MAX2688 INPUT P1dB COMPRESSION
vs. SUPPLY VOLTAGE AND TEMPERATURE
MAX2686 toc10
1dB GAIN DESENSE
vs. BLOCKER FREQUENCY
MAX2686 toc11
-4
-5
-6
INPUT P1dB (dBm)
-7
-8
-9
-10
-11
-12
1.6
1.8
2.0
2.2
2.4
2.6
2.8
3.0
3.2
SUPPLY VOLTAGE (V)
T
A
= -40°C
T
A
= +85°C
T
A
= +25°C
5
0
BLOCKER POWER (dBm)
-5
-10
-15
-20
-25
500
1000
1500
2000
MAX2688
MAX2686
2500
BLOCKER FREQUENCY (MHz)
4
MAX2686 toc09
(TONE 1 AT 1713MHz, -27dBm; TONE 2 AT 1851MHz, -39dBm)
12
MAX2688 OUT-OF-BAND IIP3
vs. SUPPLY VOLTAGE AND TEMPERATURE
MAX2686 INPUT P1dB COMPRESSION
vs. SUPPLY VOLTAGE AND TEMPERATURE
-6
MAX2686 toc07
(TWO TONES LOCATED AT 1MHz AND 2MHz OFFSET WITH -30dBm/TONE)
6
(TONE 1 AT 1713MHz, -27dBm; TONE 2 AT 1851MHz, -39dBm)
2.0
GPS/GNSS Low-Noise Amplifiers
Bump Configuration
TOP VIEW
+
V
CC
A1
MAX2686
MAX2688
MAX2686/MAX2688
A2
RFOUT (SHDN)
RFIN
B1
B2
GND
WLP
Bump Description
BUMP
A1
A2
B1
B2
NAME
V
CC
RFOUT
(SHDN)
RFIN
GND
FUNCTION
Supply Voltage. Bypass to ground with a 10pF capacitor as close as possible to the IC.
RF Output/SHDN Input. RFOUT is internally matched to 50I and pulled up to V
CC
through a 1MI
resistor.
SHDN
is shared with the RFOUT bump. The devices are in active mode by default once
V
CC
is applied. RFOUT(SHDN) can be pulled to a DC low externally to shut down the IC.
RF Input. Requires a DC-blocking capacitor and external matching components.
Ground. Connect to the PCB ground plane.
Detailed Description
The MAX2686/MAX2688 are LNAs designed for GPS
L1, Galileo, and GLONASS applications. The devices
feature an optional power-shutdown control mode to
eliminate the need for an external supply switch. The
devices achieve high gain, ultra-low-noise figure, and
excellent linearity.
The devices require an off-chip input matching. Only
an inductor in series with a DC-blocking capacitor is
needed to form the input matching circuit. The
Typical
Application Circuit
shows the recommended input-
matching network. These values are optimized for the
best simultaneous gain, noise figure, and return loss
performance. The value of the input coupling capacitor
affects IIP3. A smaller coupling capacitor results in lower
IIP3. The devices integrate an on-chip output matching
to 50I at the output, eliminating the need for external
matching components. Tables 1 and 2 list typical device
S parameters and K
f
values. Typical noise parameters
are shown in Tables 3 and 4.
The devices include an optional shutdown feature to
turn off the entire chip. The devices are placed in active
mode by default once V
CC
is applied, due to the on-chip
pullup resistor to V
CC
at the RFOUT bump (shared with
the
SHDN
input). To shut down the part, apply a logic-
low to the RFOUT bump through an external resistor with
an adequate value, e.g., 25kI, in order not to load the
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