MAXIM MAX2686, MAX2688 Technical data

19-5456; Rev 0; 8/10

EVALUATION KIT

AVAILABLE

GPS/GNSS Low-Noise Amplifiers

General Description

The MAX2686/MAX2688 low-noise amplifiers (LNAs) are
designed for GPS L1, Galileo, and GLONASS applica­tions. Designed in Maxim’s advanced SiGe process,
the devices achieve high gain and ultra-low-noise figure
while maximizing the input-referred 1dB compression
point and the 3rd-order intercept point. The MAX2686
provides a high gain of 19dB. The MAX2688 supplies
15dB of gain while attaining higher linearity.

The devices operate from a +1.6V to +3.3V single sup­ply. The optional shutdown feature in the devices reduc­es the supply current to less than 10FA. The devices
are available in a very small, lead-free, RoHS-compliant,

0.86mm x 0.86mm x 0.65mm wafer-level package (WLP).

Applications

Automotive Navigation

Telematics (Asset Tracking and Management)

Personal Navigation Devices (PNDs)

Cellular Phones with GPS

Notebook PCs/Ultra-Mobile PCs

Recreational, Marine Navigation

Avionics

Watches

Digital Cameras

Features

S High-Power Gain: 19dB (MAX2686)

S Ultra-Low-Noise Figure: 0.75dB (MAX2686)

S Integrated 50Ω Output Matching Circuit

S Low Supply Current: 4.1mA

S Wide Supply Voltage Range: 1.6V to 3.3V

S Low Bill of Materials: One Inductor, Two

Capacitors

S Small Footprint: 0.86mm x 0.86mm

S Thin Profile: 0.65mm

S 0.4mm-Pitch Wafer-Level Package (WLP)

Ordering Information

PART TEMP RANGE PIN-PACKAGE

MAX2686EWS+T
MAX2688EWS+T

+Denotes a lead(Pb)-free/RoHS-compliant package.
T = Tape and reel.

-40NC to +85NC

-40NC to +85NC

4 WLP
4 WLP

MAX2686/MAX2688

Typical Application Circuit

MAX2686

V

V

CC

C1

RF

INPUT

_______________________________________________________________ Maxim Integrated Products 1

CC

C2

L1

RFIN

MAX2688

A1 A2

B1 B2

MAX2686

L1 = 6.8nH
C1 = 100nF
C2 = 10pF

MAX2688

L1 = 6.2nH
C1 = 100nF
C2 = 10pF

For pricing, delivery, and ordering information, please contact Maxim Direct at 1-888-629-4642,
or visit Maxim’s website at www.maxim-ic.com.

RFOUT

RF
OUTPUT

R1
25kI

OPTIONAL SHUTDOWN

GND

SHDN

GPS/GNSS Low-Noise Amplifiers

ABSOLUTE MAXIMUM RATINGS

VCC to GND ..........................................................-0.3V to +3.6V

Other Pins to GND ...............-0.3V to (+ Operating VCC + 0.3V)

Maximum RF Input Power ............................................... +5dBm

Continuous Power Dissipation (TA = +70°C)

4-Bump WLP (derates 9.7mW/°C above +70°C) ........776mW

Maximum Current into RF Input .........................................10mA

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, VCC = 1.6V to 3.3V, TA = -40NC to +85NC, no RF signals are applied. Typical values are at VCC = 2.85V

MAX2686/MAX2688

and TA = +25NC, unless otherwise noted.) (Note 2)

PARAMETER CONDITIONS MIN TYP MAX UNITS

Supply Voltage 1.6 2.85 3.3 V

Supply Current

Digital Input Logic-High (Note 3) 1.2 V
Digital Input Logic-Low (Note 3) 0.45 V

SHDN = high

Shutdown mode, SHDN = low

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

MAX2686 4.1
MAX2688 4.1

10 µA

mA

AC ELECTRICAL CHARACTERISTICS

(MAX2686/MAX2688 EV kit, VCC = 1.6V to 3.3V, TA = -40NC to +85NC, f
TA = +25NC, unless otherwise noted.) (Note 2)

PARAMETER CONDITIONS MIN TYP MAX UNITS

RF Frequency L1 band 1575.42 MHz

VCC = 2.85V (Note 4)

Power Gain

VCC = 1.6V

Noise Figure VCC = 1.6V to 3.3V

In-Band 3rd-Order Input
Intercept Point

Out-of-Band 3rd-Order Input
Intercept Point

Input 1dB Compression Point (Note 7)

Input Return Loss 8.5 dB

2

(Note 5)

(Note 6)

MAX2686 14.7 19
MAX2688 11.9 15.4
MAX2686 14.4 18.9
MAX2688 11.6 15.3
MAX2686 0.75
MAX2688 0.8
MAX2686 -3
MAX2688 +4
MAX2686 0
MAX2688 +7
MAX2686 -10
MAX2688 -6

= 1575.42MHz. Typical values are at VCC = 2.85V and

RFIN

dBm

dBm

dBm

dB

dB

GPS/GNSS Low-Noise Amplifiers

AC ELECTRICAL CHARACTERISTICS (continued)

(MAX2686/MAX2688 EV kit, VCC = 1.6V to 3.3V, TA = -40NC to +85NC, f
TA = +25NC, unless otherwise noted.) (Note 2)

PARAMETER CONDITIONS MIN TYP MAX UNITS

Output Return Loss 15 dB
Reverse Isolation 40 dB

Note 2: Min and max limits guaranteed by test at TA = +25°C and guaranteed by design and characterization at TA = -40°C and

TA = +85°C, unless otherwise noted.

Note 3: Min and max limits guaranteed by test at TA = +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 VCC = 2.85V, TA = +25°C, and f

= 1575.42MHz. Typical values are at VCC = 2.85V and

RFIN

= 1575.42MHz, unless otherwise noted.)

RFIN

MAX2686/MAX2688

INPUT RETURN LOSS vs. FREQUENCY

0

-5

-10

-15

-20

|S11| (dB)

-25

-30

-35

-40
500 2500

FREQUENCY (MHz)

MAX2688

MAX2686

200015001000

OUTPUT RETURN LOSS vs. FREQUENCY

0

-5

-10

-15

|S22| (dB)

-20

-25

-30

-35

MAX2686

MAX2688

500 2500

MAX2686 toc01

FREQUENCY (MHz)

25

20

15

10

GAIN (dB)

5

0

-5
500 2500

MAX2686

MAX2688

FREQUENCY (MHz)

vs. SUPPLY VOLTAGE AND TEMPERATURE

(TWO TONES LOCATED AT 1MHz AND 2MHz OFFSET WITH -30dBm/TONE)

0

GAIN vs. FREQUENCY

MAX2686 toc04

200015001000

-1

-2

-3

IIP3 (dBm)

-4

-5

-6

200015001000

MAX2686 IN-BAND IIP3

TA = -40°C

1.6
SUPPLY VOLTAGE (V)

MAX2686 toc02

TA = +85°C

REVERSE ISOLATION vs. FREQUENCY

-20

-25

-30

-35

-40

-45

|S12| (dB)

-50

-55

-60

-65

-70
500 2500

TA = +25°C

3.23.02.82.62.42.22.01.8

MAX2686

MAX2688

200015001000

FREQUENCY (MHz)

MAX2686 toc05

MAX2686 toc03

3

GPS/GNSS Low-Noise Amplifiers

Typical Operating Characteristics (continued)

(MAX2686/MAX2688 EV kit. Typical values are at VCC = 2.85V, TA = +25°C, and f

= 1575.42MHz, unless otherwise noted.)

RFIN

MAX2688 IN-BAND IIP3

vs. SUPPLY VOLTAGE AND TEMPERATURE

(TWO TONES LOCATED AT 1MHz AND 2MHz OFFSET WITH -30dBm/TONE)

6

TA = -40°C

5

4

3

IIP3 (dBm)

2

1

MAX2686/MAX2688

0

1.6
SUPPLY VOLTAGE (V)

TA = +25°C

TA = +85°C

MAX2688 OUT-OF-BAND IIP3

vs. SUPPLY VOLTAGE AND TEMPERATURE

(TONE 1 AT 1713MHz, -27dBm; TONE 2 AT 1851MHz, -39dBm)

12

TA = +25°C

10

8

6

IIP3 (dBm)

4

2

0

1.6

TA = +85°C

TA = -40°C

SUPPLY VOLTAGE (V)

MAX2686 OUT-OF-BAND IIP3

vs. SUPPLY VOLTAGE AND TEMPERATURE

(TONE 1 AT 1713MHz, -27dBm; TONE 2 AT 1851MHz, -39dBm)

2.0

1.5

MAX2686 toc06

3.23.02.82.62.42.22.01.8

1.0

0.5

0

-0.5

IIP3 (dBm)

-1.0

-1.5

-2.0

-2.5

-3.0

1.6

TA = -40°C

TA = +85°C

SUPPLY VOLTAGE (V)

TA = +25°C

MAX2686 toc07

3.23.02.6 2.82.0 2.2 2.41.8

MAX2686 INPUT P1dB COMPRESSION

vs. SUPPLY VOLTAGE AND TEMPERATURE

-6

-7

MAX2686 toc08

3.23.02.82.62.42.22.01.8

-8

-9

-10

-11

-12

INPUT P1dB (dBm)

-13

-14

-15

-16

1.6

TA = -40°C

TA = +25°C

TA = +85°C

SUPPLY VOLTAGE (V)

MAX2686 toc09

3.23.02.6 2.82.0 2.2 2.41.8

MAX2688 INPUT P1dB COMPRESSION

vs. SUPPLY VOLTAGE AND TEMPERATURE

-4

-5

-6

-7

-8

-9

INPUT P1dB (dBm)

-10

-11

-12

1.6

TA = +25°C

TA = +85°C

= -40°C

T

A

SUPPLY VOLTAGE (V)

5

MAX2686 toc10

3.23.01.8 2.0 2.2 2.62.4 2.8

0

-5

-10

-15

BLOCKER POWER (dBm)

-20

-25
500 2500

1dB GAIN DESENSE

vs. BLOCKER FREQUENCY

MAX2688

MAX2686

200015001000

BLOCKER FREQUENCY (MHz)

MAX2686 toc11

4

GPS/GNSS Low-Noise Amplifiers

Bump Configuration

TOP VIEW

+

V

A1 A2

CC

MAX2686
MAX2688

B1 B2

RFIN

WLP

Bump Description

BUMP NAME FUNCTION

A1 V

A2

B1 RFIN RF Input. Requires a DC-blocking capacitor and external matching components.
B2 GND Ground. Connect to the PCB ground plane.

CC

RFOUT

(SHDN)

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 VCC through a 1MI
resistor. SHDN is shared with the RFOUT bump. The devices are in active mode by default once
VCC is applied. RFOUT(SHDN) can be pulled to a DC low externally to shut down the IC.

RFOUT (SHDN)

GND

MAX2686/MAX2688

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.

Input and Output Matching

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 input­matching 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 Kf values. Typical noise parameters
are shown in Tables 3 and 4.

Shutdown

The devices include an optional shutdown feature to
turn off the entire chip. The devices are placed in active
mode by default once VCC is applied, due to the on-chip
pullup resistor to VCC at the RFOUT bump (shared with
the SHDN input). To shut down the part, apply a logic­low to the RFOUT bump through an external resistor with
an adequate value, e.g., 25kI, in order not to load the
RF output signal during active operation.

5

GPS/GNSS Low-Noise Amplifiers

Table 1. MAX2686 Typical S Parameter Values and K-Factor

FREQ.

(MHz)

1000 -2.9 -26.8 6.2 -109.0 -53.0 169.0 -1.4 -57.0 15.2
1100 -3.1 -27.2 7.9 -110.0 -53.0 163.0 -2.0 -64.0 17.4
1200 -3.4 -27.0 9.5 -113.0 -52.0 157.0 -2.9 -73.0 18.0
1300 -3.5 -28.0 12.8 -128.0 -58.0 -176.0 -7.0 -99.0 40.6
1400 -3.5 -28.3 12.8 -128.0 -56.0 -164.0 -7.0 -99.0 32.3
1500 -3.9 -29.0 13.9 -144.0 -49.0 -166.0 -14.1 -124.0 16.3
1575 -4.1 -27.0 14.1 -156.0 -47.0 164.0 -29.0 -113.0 13.5
1600 -4.1 -27.7 14.1 -160.0 -48.0 154.0 -21.2 68.0 15.0
1700 -4.0 -28.1 13.9 -174.0 -54.0 166.0 -9.0 42.0 26.4
1800 -4.2 -28.9 12.9 170.0 -49.0 -160.0 -5.3 26.4 13.6

MAX2686/MAX2688

1900 -4.4 -29.0 11.4 160.0 -47.3 -176.0 -3.3 13.9 10.2
2000 -4.5 -28.9 9.9 153.0 -46.5 170.0 -2.3 5.0 8.5

S11

MAG

(dB)

S11

PHASE

(DEGREES)

S21

MAG

(dB)

S21

PHASE

(DEGREES)

S12

MAG

(dB)

Table 2. MAX2688 Typical S Parameter Values and K-Factor

FREQ.

(MHz)

1000 -3.2 -18.0 3.6 -116.0 -54.0 150.0 -1.3 -53.0 22.5
1100 -3.4 -17.5 5.2 -116.9 -55.0 147.0 -1.9 -60.6 29.9
1200 -3.6 -16.8 6.8 -119.0 -56.6 147.0 -2.7 -69.2 40.5
1300 -3.5 -17.2 8.6 -124.0 -63.0 -144.0 -4.2 -80.0 90.4
1400 -3.8 -18.0 10.1 -137.5 -49.8 -145.0 -7.7 -95.0 23.7
1500 -4.0 -16.5 10.7 -151.0 -47.3 174.0 -14.5 -107.7 19.7
1575 -4.1 -15.8 11.0 -161.5 -48.3 169.0 -35.0 151.0 22.4
1600 -4.1 -15.7 11.1 -164.9 -48.7 159.0 -23.4 74.9 23.1
1700 -4.1 -16.6 11.0 -179.0 -55.0 175.0 -9.7 50.0 43.1
1800 -4.2 -16.7 10.2 165.0 -48.0 -151.0 -5.2 34.0 16.5
1900 -4.4 -16.6 8.6 155.0 -46.0 -164.0 -3.2 21.0 11.9
2000 -4.5 -16.3 7.2 149.0 -45.6 -179.0 -2.3 12.0 10.6

S11

MAG

(dB)

S11

PHASE

(DEGREES)

S21

MAG

(dB)

S21

PHASE

(DEGREES)

S12

MAG

(dB)

S12

PHASE

(DEGREES)

S12

PHASE

(DEGREES)

S22

MAG

(dB)

S22

MAG

(dB)

S22

PHASE

(DEGREES)

S22

PHASE

(DEGREES)

K

f

K

f

Table 3. MAX2686 Typical Noise Parameters (VCC = 2.85V, TA = +25NC)

FREQUENCY (MHz) FMIN (dB)

1550 0.63 0.43 45.7 8.25
1560 0.63 0.43 46.0 8.23
1570 0.63 0.42 46.3 8.22
1575 0.63 0.42 46.4 8.22
1580 0.63 0.42 46.5 8.21
1590 0.63 0.42 46.8 8.20
1600 0.64 0.42 47.1 8.19

6

|G

| |G

OPT

OPT

| ANGLE

RN (I)

GPS/GNSS Low-Noise Amplifiers

Table 4. MAX2688 Typical Noise Parameters (VCC = 2.85V, TA = +25NC)

FREQUENCY (MHz) FMIN (dB)

1550 0.73 0.42 59.0 8.34
1560 0.74 0.42 59.4 8.31
1570 0.74 0.42 59.7 8.29
1575 0.74 0.42 59.9 8.28
1580 0.74 0.42 60.1 8.27
1590 0.74 0.41 60.5 8.25
1600 0.74 0.41 60.8 8.22

|G

| |G

OPT

OPT

| ANGLE

MAX2686/MAX2688

RN (I)

Applications Information

A properly designed PCB is essential to any RF micro­wave circuit. Use controlled-impedance lines on all
high-frequency inputs and outputs. Bypass VCC with
decoupling capacitors located close to the device. For
long VCC lines, it may be necessary to add decoupling
capacitors. Locate these additional capacitors further
away from the device package. Proper grounding of
the GND pin is essential. If the PCB uses a topside RF
ground, connect it directly to the GND pin. For a board
where the ground is not on the component layer, connect
the GND pin to the board with multiple vias close to the
package.

Refer to www.maxim-ic.com for the MAX2686 EV kit
schematic, Gerber data, PADS layout file, and BOM
information.

Chip Information

PROCESS: SiGe BiCMOS

Package Information

For the latest package outline information and land patterns,
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.

PACKAGE

TYPE

4 WLP W40A0+1

PACKAGE

CODE

OUTLINE

NO.

21-0480 —

LAND

PATTERN NO.

7

GPS/GNSS Low-Noise Amplifiers

Revision History

REVISION

NUMBER

0 8/10 Initial release —

REVISION

DATE

MAX2686/MAX2688

DESCRIPTION

PAGES

CHANGED

Maxim cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim product. No circuit patent licenses are implied.
Maxim reserves the right to change the circuitry and specifications without notice at any time.

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