Quectel | L80 EVB | L80 Hardware Design

L80 Hardware Design
GPS Module Series
Rev. L80_Hardware_Design_V1.0
Date: 2013-07-25
www.quectel.com
GPS Module
L80 Hardware Design
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Tel: +86 21 5108 6236
Mail:info@quectel.com
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About the document
History
Revision
V1.0
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Date
Author
Description
2013-07-25
Tony GAO
Initial
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Contents
About the document .................................................................................................................................2
Contents .....................................................................................................................................................3
Table Index .................................................................................................................................................5
Figure Index ...............................................................................................................................................6
1
Introduction ........................................................................................................................................7
2
Description .........................................................................................................................................8
2.1. General Description ...................................................................................................................8
2.2. Key Features ..............................................................................................................................9
2.3. Block Diagram ..........................................................................................................................10
2.4. Evaluation Board ......................................................................................................................10
2.5. The Protocols Module Supports .............................................................................................. 11
3
Application........................................................................................................................................12
3.1. Pin Assignment ........................................................................................................................12
3.2. Pin Definition ............................................................................................................................12
3.3. Power Supply ...........................................................................................................................14
3.4. Operating Modes......................................................................................................................16
3.4.1. Full On Mode ................................................................................................................16
3.4.2. Standby Mode ..............................................................................................................17
3.4.3. Backup Mode ...............................................................................................................17
3.4.4. Periodic Mode ..............................................................................................................19
3.4.5. AlwaysLocateTM Mode .................................................................................................21
3.5. Reset ........................................................................................................................................22
3.6. UART Interface.........................................................................................................................23
3.7. EASY Technology ....................................................................................................................25
3.8. Multi-tone AIC...........................................................................................................................25
3.9. LOCUS .....................................................................................................................................25
3.10. Antenna Advisor .......................................................................................................................26
4
Antenna Interface .............................................................................................................................27
4.1. Recommended Circuit for Antenna ..........................................................................................27
4.1.1. Internal Patch Antenna .................................................................................................27
4.1.1.1. 15*15*4 Patch Antenna .......................................................................................27
4.1.1.2. PCB Design Guide ..............................................................................................28
4.1.2. External Active Antenna ...............................................................................................29
4.2. Antenna Detection and Handling Mechanism .........................................................................31
5
Electrical, Reliability and Radio Characteristics ..........................................................................33
5.1. Absolute Maximum Ratings .....................................................................................................33
5.2. Operating Conditions ...............................................................................................................34
5.3. Current Consumption ...............................................................................................................34
5.4. Electro-static Discharge ...........................................................................................................35
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5.5.
Reliability Test ..........................................................................................................................35
6
Mechanics .........................................................................................................................................37
6.1. Mechanical View of the Module ...............................................................................................37
6.2. Bottom Dimension and Recommended Footprint....................................................................38
6.3. Top View of the Module ............................................................................................................39
6.4. Bottom View of the Module ......................................................................................................39
7
Manufacturing ..................................................................................................................................40
7.1. Assembly and Soldering ..........................................................................................................40
7.2. Moisture Sensitivity ..................................................................................................................41
7.3. ESD Safe..................................................................................................................................41
7.4. Tape and Reel ..........................................................................................................................41
7.5. Ordering Information ................................................................................................................42
8
Appendix Reference ........................................................................................................................43
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Table Index
TABLE 1: MODULE KEY FEATURES ................................................................................................................. 9
TABLE 2: THE PROTOCOLS SUPPORTED BY THE MODULE ....................................................................... 11
TABLE 3: PIN DESCRIPTION ........................................................................................................................... 12
TABLE 4: MODULE STATES SWITCH ............................................................................................................. 16
TABLE 5: DEFAULT CONFIGURATIONS ......................................................................................................... 17
TABLE 6: PMTK COMMAND FORMAT ............................................................................................................ 19
TABLE 7: STATUS OF THE ANTENNA ............................................................................................................. 26
TABLE 8: ANTENNA SPECIFICATION FOR L80 MODULE WITH GROUND PLANE 100MM×60MM............ 27
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TABLE 9: RECOMMENDED ACTIVE ANTENNA SPECIFICATION ................................................................. 30
TABLE 10: GPTXT - STATUS OF ANTENNA.................................................................................................... 32
TABLE 11: ABSOLUTE MAXIMUM RATINGS .................................................................................................. 33
TABLE 12: THE MODULE POWER SUPPLY RATINGS .................................................................................. 34
TABLE 13: THE MODULE CURRENT CONSUMPTION .................................................................................. 34
TABLE 14: THE ESD ENDURANCE TABLE (TEMPERATURE: 25℃, HUMIDITY: 45 %) ............................... 35
TABLE 15: RELIABILITY TEST ......................................................................................................................... 35
TABLE 16: TRAY PACKING .............................................................................................................................. 42
TABLE 17: ORDERING INFORMATION ........................................................................................................... 42
TABLE 18: RELATED DOCUMENTS ................................................................................................................ 43
TABLE 19: TERMS AND ABBREVIATIONS ...................................................................................................... 43
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Figure Index
FIGURE 1: BLOCK DIAGRAM .......................................................................................................................... 10
FIGURE 2: PIN ASSIGNMENT ......................................................................................................................... 12
FIGURE 3: INTERNAL POWER CONSTRUCTION.......................................................................................... 14
FIGURE 4: REFERENCE CIRCUIT FOR POWER SUPPLY ............................................................................ 15
FIGURE 5: REFERENCE CHARGING CIRCUIT FOR CHARGEABLE BATTERY .......................................... 15
FIGURE 6: THE EXTERNAL SWITCH CIRCUIT FOR TIMER ......................................................................... 18
FIGURE 7: SEIKO MS920SE CHARGE AND DISCHARGE CHARACTERISTICS ......................................... 19
FIGURE 8: PERIODIC MODE ........................................................................................................................... 21
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TM
FIGURE 9: ALWAYSLOCATE
MODE ............................................................................................................ 22
FIGURE 10: REFERENCE RESET CIRCUIT USING OC CIRCUIT ................................................................. 23
FIGURE 11: RESTART TIMING ........................................................................................................................ 23
FIGURE 12: CONNECTION OF SERIAL INTERFACES .................................................................................. 24
FIGURE 13: RS-232 LEVEL SHIFT CIRCUIT ................................................................................................... 24
FIGURE 14: PATCH ANTENNA TEST RESULT WITH GROUND PLANE 100MM×60MM .............................. 28
FIGURE 15: L80 MODULE PLACEMENT GUIDE ............................................................................................ 29
FIGURE 16: REFERENCE DESIGN FOR ACTIVE ANTENNA ........................................................................ 30
FIGURE 17: PATCH ANTENNA STATUS DESCRIPTION IN GPSTXT ............................................................ 31
FIGURE 18: MECHANICAL VIEW(UNIT: MM) ............................................................................................. 37
FIGURE 19: BOTTOM DIMENSION(UNIT: MM) .......................................................................................... 38
FIGURE 20: FOOTPRINT OF RECOMMENDATION(UNIT: MM) ................................................................ 38
FIGURE 21: TOP VIEW OF THE MODULE ...................................................................................................... 39
FIGURE 22: BOTTOM VIEW OF THE MODULE .............................................................................................. 39
FIGURE 23: RAMP-SOAK-SPIKE-REFLOW OF FURNACE TEMPERATURE ............................................... 40
FIGURE 24: TAPE AND REEL SPECIFICATION .............................................................................................. 41
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1
Introduction
This document defines and specifies L80 GPS module. It describes L80 module hardware interfaces and
its external application reference circuits, mechanical size and air interface.
This document can help you quickly understand the interface specifications, electrical and mechanical
details of L80 module. Other documents such as L80 software application notes and user guider are also
provided for you. These documents can ensure you use L80 module to design and set up applications
quickly.
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2
Description
2.1. General Description
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L80 GPS module with an embedded patch antenna (15mmx15mmx4mm) and LNA brings high
performance of MTK positioning engine to the industrial applications. It is able to achieve the industry’s
highest level of sensitivity, accuracy and TTFF with the lowest power consumption in a small-footprint
lead-free package. With 66 search channels and 22 simultaneous tracking channels, it acquires and
tracks satellites in the shortest time even at indoor signal level. The embedded flash memory provides
capacity for users to store some useful navigation data and allows for future updates.
L80 module combines with many advanced features including EASY, AIC, LOCUS, AlwaysLocateT M and
Antenna Advisor. These features are beneficial to accelerate TTFF, improve sensitivity, save
consumption and detect antenna status for GPS system. The module supports various location,
navigation and industrial applications including autonomous GPS, SBAS (including WAAS, EGNOS,
MSAS, and GAGAN), QZSS, and AGPS.
L80 simplifies the device’s design and cost because of embedded Patch Antenna and LNA. Furthermore,
L80 not only supports automatic antenna switching function, which can achieve switching between
external active antenna and internal patch antenna but also supports external active antenna detection
and short protection. The detection and notification of different external active antenna status will be
shown in the NMEA message including external active antenna connection, open circuit for antenna and
antenna shortage. So host can query the external active antenna status timely and conveniently.
L80 module is a SMD type module with the compact 16mm x 16mm x 6.45mm form factor, which can be
embedded in your applications through the 12-pin pads with 2.54mm pitch. It provides necessary
hardware interfaces between the module and main board.
The module is fully ROHS compliant to EU regulation.
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2.2. Key Features
Table 1: Module Key Features
Feature
Implementation
Power Supply

Supply Voltage: 2.8V ~ 4.3V
Power Consumption




Acquisition
Tracking
Standby
Backup
Receiver Type


GPS L1 1575.42MHz C/A Code
66 search channels, 22 simultaneous tracking channels
Sensitivity



Acquisition
Re-acquisition
Tracking
-148dBm
-160dBm
-165dBm
TTFF (EASY enabled)



Cold Start
Warm Start
Hot Start
15s typ.@-130dBm
5s typ.@-130dBm
1s typ. @-130dBm
TTFF (EASY disabled)



Cold Start (Autonomous)
Warm Start (Autonomous)
Hot Start (Autonomous)
Horizontal Position
Accuracy (Autonomous)

<2.5m CEP@-130dBm
Max Update Rate

Up to 10Hz,1Hz by default
Accuracy of 1PPS Signal


Typical accuracy <15ns (Time service is not supported)
Time pulse width 100ms
Velocity Accuracy

Without Aid
0.1m/s
Acceleration Accuracy

Without Aid
0.1m/s²
Dynamic Performance



Maximum Altitude 18,000m
Maximum Velocity 515m/s Maximum
Acceleration
4G



UART Port: TXD1 and RXD1
Supports baud rate from 4800bps to 115200bps,9600bps by default
UART port is used for NMEA output, MTK proprietary commands
input and firmware upgrade
Temperature Range


Normal operation: -40°C ~ +85°C
Storage temperature: -45°C ~ +125°C
Physical Characteristics


Size: 16±0.15 x 16±0.15 x 6.45±0.1mm
Weight: Approx. 6.0g
typical : 3.3V
25mA@ VCC=V_BCKP=3.3V
20mA@ VCC= V_BCKP =3.3V
1.0mA @ VCC= V_BCKP =3.3V
7uA@ V_BCKP=3.3V
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UART Port
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35s typ.@-130dBm
30s typ.@-130dBm
1s typ.@-130dBm
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NOTES
1. The power consumption is measured in the open sky with internal patch antenna, meanwhile, EASY,
AIC and SBAS are enabled.
2. If the external active antenna is used, VCC pin will supply power for external active antenna. The
typical additional current consumption is about 11mA@3.3V.
3. The performance of external active antenna is similar to that of internal patch antenna expect for
power consumption.
2.3. Block Diagram
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The following figure shows a block diagram of L80 module. It consists of a single chip GPS IC which
includes RF part and Baseband part, a SPDT, a patch antenna, a LNA, a SAW filter, a TCXO, a crystal
oscillator, short protection and antenna detection circuit for active antenna.
SAW
Filter
LNA
RF Front
End
Active
Interference
Cancellation
Integrated
LNA
15*15*4 Patch
Antenna
SPDT
TCXO
26M
GPS
Engine
ROM
Fractional-N
Synthesizer
ARM7
Processor
RAM
Flash
RTC
EX_ ANT
GPIO
XTAL 32.768K
Protection
Circuit
Active
Antenna
Detection
Peripheral
Controller
PMU
UART
RESET
1PPS
TIMER
V_BCKP
VCC
Figure 1: Block Diagram
2.4. Evaluation Board
In order to help you use L80 module on your applications, Quectel supplies an Evaluation Board (EVB)
with micro USB serial cable and other peripherals to test the module.
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For more details, please refer to the document [1].
2.5. The Protocols Module Supports
Table 2: The Protocols Supported by the Module
Protocol
Type
NMEA
Output, ASCII, 0183, 3.01
PMTK
NOTE
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Input, MTK proprietary protocol
Please refer to document [2] about NMEA standard protocol and MTK proprietary protocol.
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3
Application
The module is equipped with a 12-pin 2.54mm pitch SMT pad that connects to your application platform.
Sub-interfaces included in these pads are described in details in the following chapters.
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3.1. Pin Assignment
1PPS
6
NC
V_BCKP
5
9
NC
VCC
4
10
RESET
GND
3
11
EX_ANT
TXD1
2
12
GND
RXD1
1
7
TIMER
8
L80
(Top View)
Figure 2: Pin Assignment
3.2. Pin Definition
Table 3: Pin Description
Power supply
Pin Name
Pin No.
I/O
Description
DC Characteristics
Comment
Vmax= 4.3V
Vmin=2.8V
Vnom=3.3V
Supply current of no less
than 100mA.
Vmax=4.3V
Vmin=1.5V
Supply power for RTC
domain .The V_BCKP pin
VCC
4
I
Main power
supply
V_BCKP
5
I
Backup power
supply
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Vnom=3.3V
can be directly supplied
power by battery or
connect it to VCC.
Description
DC Characteristics
Comment
System reset
VILmin=-0.3V
VILmax=0.8V
VIHmin=2.0V
VIHmax=3.6V
Low level active. If
unused, keep this pin
open or connect it to VCC.
Reset
Pin Name
Pin No.
RESET
UART port
Pin Name
RXD1
TXD1
10
I/O
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Pin No.
1
I/O
I
Description
DC Characteristics
Receive data
VILmin=-0.3V
VILmax=0.8V
VIHmin=2.0V
VIHmax= 3.6V
Comment
2
O
Transmit data
VOLmin=-0.3V
VOLmax=0.4V
VOHmin=2.4V
VOHmax=3.1V
Pin No.
I/O
Description
DC Characteristics
Comment
I
external active
antenna RF
input
Characteristic
impedance of 50Ω
If unused, keep this pin
open.
I/O
Description
DC Characteristics
Comment
O
One pulse per
second
VOLmin=-0.3V
VOLmax=0.4V
VOHmin=2.4V
VOHmax=3.1V
Synchronized at rising
edge, the pulse width
is100ms. If unused, keep
this pin open.
O
An open drain
output signal
can be used to
control GPS
module main
power on/off
VOLmin=-0.3V
VOLmax=0.4V
VOHmin=2.4V
VOHmax= 3.1V
It belongs to RTC domain.
If unused, keep this pin
open or connect to Ground
externally.
RF interface
Pin Name
EX_ANT
11
Other interfaces
Pin Name
1PPS
TIMER
Pin No.
6
7
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3.3. Power Supply
VCC pin supplies power for BB, RF, I/O, LNA, short protection and antenna detection circuit. The load
current of VCC varies according to the VCC level, processor load, the number of tracked satellites and the
rate of satellite re-acquisition. Using external active antenna will consume additional 11mA from our
module. So it is important to supply sufficient current and make the power clean and stable. VCC supply
ripple voltage should meet the requirement: 54 mV (RMS) max @ f = 0… 3MHz and 15 mV (RMS) max @
f > 3MHz. You should choose the LDO without built-in output high-speed discharge function to keep long
output voltage drop-down period. The decouple combination of 10uF and 100nF capacitor is
recommended nearby VCC pin.
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The V_BCKP pin supplies power for RTC domain. It should be valid when power on the module. The
voltage of RTC domain ranges from 1.5V to 4.3V. In order to achieve a better TTFF, RTC domain should
be valid all the time. It can supply power for SRAM memory in RTC domain which contains all the
necessary GPS information for quick start-up and a small amount of user configuration variables.
The module’s internal power construction is shown as below.
VCC supplies power for PMU and V_BCKP supplies power for RTC domain. TIMER signal, highlighted as
red line in the following figure, belongs to RTC domain and can be used to control the power switch on/off.
For more details about TIMER function, please refer to chapter 3.4.3.
L80_ Module
Power Switch
4
PMU
VCC
ARM
5
Logic
Circuit
7
V_BCKP
TIMER
RTC
Power RTC
Figure 3: Internal Power Construction
Here, we list some power solutions for L80 module, the reference design is shown as below.
The simplest power circuit for L80 module is 3.3V power source connect to VCC pin and V_BCKP pin of
the module directly. In this case, every time to restart the module, the cold start will be implemented. It
doesn’t support backup mode introduced in chapter 3.4.3, as well as EASY technology introduced in
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chapter 3.7.
3.3V
4
C1
10uF
VCC
C2
100nF
L80 MODULE
V_BCKP
5
C3
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100nF
Figure 4: Reference Circuit for Power Supply
Another power solution can implement a backup battery in the condition of VCC off to maintain V_BCKP
on. It will enter into backup mode and benefit TTFF in next stating module. For more details, please refer
to chapter 3.4.3.
Power source supplies power for the VCC pin, The V_BCKP pin can be directly supplied power by an
external rechargeable battery. Furthermore, it is necessary to add an external charging circuit for
rechargeable battery.
Customer can apply a power switch circuit in the front VCC pin for more power saving functions when it is
coordinated with TIMER pin. The detail schematic of power switch circuit is shown in Figure 6.
R2 NC
Power Switch
3.3V
VCC
C1 C2
D1
Charging
Circuit
10uF
4
100nF
TIMER
L80 MODULE
R1
1K
Rechargeable
Battery
5
C3
V_ BCKP
C4
4.7uF
100nF
Figure 5: Reference Charging Circuit for Chargeable Battery
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NOTE
VCC does not supply power for RTC domain in L80 module internally, so the V_BCKP pin must be
powered externally
3.4. Operating Modes
The table below briefly illustrates the relationship among different operating modes of L80 module.
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Table 4: Module States Switch
Current
Mode
Next Mode
Backup
Standby
Full on
Periodic
Backup
N/A
N/A
Refer to
chapter 3.4.3
N/A
Standby
N/A
N/A
Send any
data via UART
N/A
N/A
Full on
Refer to
chapter 3.4.3
PMTK
161
N/A
Refer to
chapter 3.4.4
Refer to
chapter 3.4.5
Periodic
N/A
N/A
Refer to
chapter 3.4.4
N/A
N/A
Always
Locate
N/A
N/A
Refer to
chapter 3.4.5
N/A
N/A
NOTE
AlwaysLocate
N/A
Please refer to document [2] about MTK proprietary protocol for more details.
3.4.1. Full On Mode
Full on mode includes tracking mode and acquisition mode. Acquisition mode is defined as the module
starts to search satellites, determine visible satellites and coarse carrier frequency and code phase of
satellite signals. When the acquisition is completed, it switches to tracking mode automatically. Tracking
mode is defined as the module keeps tracking satellites and demodulates the navigation data from the
specific satellites.
When the combination of VCC and V_BCKP is valid, the module will enter into full on mode automatically
and follow the default configurations as below. You can refer to chapter 3.3 about internal power
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construction to have a good comprehension. You can also use PMTK commands to change the
configurations to satisfy your requirements.
Table 5: Default Configurations
Item
Configuration
Baud rate
9600bps
Protocol
NMEA
Update rate
SBAS
AIC
LOCUS
EASY
Comment
RMC, VTG, GGA, GSA, GSV, GLL and
GPTXT(MTK proprietary protocol)
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1Hz
Enable
Enable
Disable
Enable
EASY will be disabled automatically when update rate
exceeds 1Hz.
3.4.2. Standby Mode
Standby mode is a low-power mode. In standby mode, the internal core and I/O power domain are still
active, but RF and TCXO are powered off, the module stops satellites search and navigation. UART is still
accessible like PMTK commands or any other data, but there is no NMEA messages output.
Sending PMTK command “$PMTK161,0*28” will make L80 module enter into standby mode. Sending any
data via UART can wake the module up. When the module exit from standby mode, it will use all internal
aiding information like GPS time, Ephemeris, Last Position etc, resulting to a fastest possible TTFF in
either Hot or Warm start. The typical standby current consumption in this way is about 1mA @VCC=3.3V.
NOTE
When the external active antenna is used, an additional 11mA will be consumed because the VCC still
supply power for external active antenna in standby mode.
3.4.3. Backup Mode
Backup mode is a lower power mode than standby mode. In this mode, only the backup supply V_BCKP
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is powered on while the main supply VCC is switched off by host or the TIMER signal of L80. In order to
enter into backup mode autonomously via the TIMER pin, an external switch circuit is necessary. The
following figure has shown a typical reference design about the switch circuit for TIMER.
Power Switch
LDO_3.3V
R1
47K
VIN
VOUT
EN
GND
VCC_3.3V
D1
U1
ADP191
TIMER
D2
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GPS_EN
Figure 6: The External Switch Circuit for TIMER
NOTES
1.
2.
3.
4.
U1 is an integrated power switch component. The part number ADP191 is recommended. U1 also
can be replaced by discrete components, please refer to document [3] for more details.
TIMER pin also can be used to control the EN pin of a LDO, please refer to document [3] for more
details.
TIMER and GPS_EN signals form an “OR” logic via the Schottky diodes D1 and D2. GPS_EN is a
GPIO signal comes from the host.
TIMER is an open drain output signal. When TIMER pin is used, please pull it high by using an
external resistor. R1 is the pull-up resistor for TIMER signal.
Keeping GPS_EN signal low and sending PMTK command“$PMTK225,4*2F” will make L80 module enter
into backup mode forever. When this command is executed successfully, TIMER signal will be pulled
down to close the power switch, so L80 module can go into backup mode as the main power VCC is cut
off. For this case, pulling the GPS_EN signal high by host is the only way to wake the module up.
In backup mode, L80 module stops to acquire and track satellites. UART is not accessible. But the
backed-up memory in RTC domain which contains all the necessary GPS information for quick start-up
and a small amount of user configuration variables is alive. Due to the backed-up memory, EASY
technology is available. The typical consumption in backup mode can be as low as 7uA.
As the main power supply for V_BCKP pin is battery. Coin-type Rechargeable Capacitor such as
MS920SE from Seiko can be used and Schottky diode such as RB520S30T1G from ON Semiconductoris
recommended to be used here for its low voltage drop.
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Figure 7: Seiko MS920SE Charge and Discharge Characteristics
3.4.4. Periodic Mode
Periodic mode is a power saving mode of L80 that can control the full on mode and standby/backup mode
periodically to reduce power consumption. It contains periodic standby mode and periodic backup mode.
The format of the command which enters into periodic mode is as follows:
Table 6: PMTK Command Format
Format:
$PMTK225,<Type>,<Run_time>,<Sleep_time>,<2nd_run_time>,<2nd_sleep_time>*<checksum><
CR><LF>
Parameter
Format
Description
Decimal
Type=1 for Periodic Backup Mode
Type=2 for Periodic Standby Mode
Decimal
Full on period (ms)
Sleep_time
Decimal
Standby/Backup period (ms)
2nd_run_time
Decimal
Full on period (ms) for extended acquisition in case GPS
module acquisition fails during the Run_time
2nd_sleep_time
Decimal
Standby/Backup period (ms) for extended sleep in case
GPS module acquisition fails during the Run_time
Checksum
Hexadecimal
Hexadecimal checksum
Type
Run_time
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Example:
$PMTK225,1,3000,12000,18000,72000*16<CR><LF>
$PMTK225,2,3000,12000,18000,72000*15<CR><LF>
Sending “$PMTK225,0*2B” in any time will make the module to full on mode from periodic standby mode.
Sending “$PMTK225,0*2B” just in Run_time or 2nd_run_time can make the module to full on mode from
periodic backup mode.
NOTES
1.
2.
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Periodic backup mode needs the external switch circuit to support, please refer to chapter 3.4.3.
Before entering into periodic backup mode, please ensure the GPS_EN signal is low and power
supply for V_BCKP is alive.
The following figure has shown the operation of periodic mode. When you send PMTK command, the
module will be in the full on mode firstly. After several minutes, the module will enter into the periodic
mode and follow the parameters set by you. When the module fails to fix the position in run time, the
module will switch to 2nd_run_timeand 2nd_sleep_time automatically. As long as the module fixes the
position again, the module will return to Run_time and Sleep_time.
Please ensure the module is in the tracking state before entering into periodic mode. Otherwise the
module will have a risk of failure to track the satellites. If GPS module is located in weak signal
environment, it is better to set the longer 2nd_run_time to ensure the success of re-acquisition.
The average current value can be calculated by the following formula:
I periodic= (I tracking× T1+Istandby/backup× T2)/ (T1+T2) T1: Run_time, T2: Sleep_time
Example:
PMTK225,2,3000,12000,18000,72000*15 for periodic mode with 3s in tracking mode and 12s in standby
mode. The average current consumption is calculated below:
I periodic=(I tracking× T1+I standby× T2 )/(T1+T2)=(20mA× 3s + 1mA× 12s)/(3s+12s)≈4.8 (mA)
PMTK225,1,3000,12000,18000,72000*16 for periodic mode with 3s in tracking mode and 12s in backup
mode. The average current consumption is calculated below:
I periodic=(I tracking× T1+I backup× T2 )/(T1+T2)=(20mA× 3s + 0.007mA× 12s)/(3s+12s)≈4.0 (mA)
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Power
Full on
Run_time Run_time
Sleep_time Sleep_time
2nd_run_time
2nd_sleep_time
2nd_run_time
2nd_sleep_time
Run_time Run_time
Sleep_time Sleep_time
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Figure 8: Periodic Mode
3.4.5. AlwaysLocateTM Mode
AlwaysLocateTM is an intelligent power saving mode. It contains AlwaysLocateTM backup mode and
AlwaysLocateTM standby mode.
AlwaysLocateTM standby mode supports the module to switch automatically between full on mode and
standby mode. According to the environmental and motion conditions, the module can adaptively adjust
the full on time and standby time to achieve a balance between positioning accuracy and power
consumption. Sending “$PMTK225,8*23” and the module returning: “$PMTK001,225,3*35” means the
module accesses AlwaysLocateTM standby mode successfully. It will benefit power saving in this mode.
Sending “$PMTK225,0*2B” in any time will make the module back to full on mode.
AlwaysLocateTM backup mode is similar to AlwaysLocateTM standby mode. The difference is that
AlwaysLocateTM backup mode switches automatically between full on mode and backup mode. The
PMTK command to enter into AlwaysLocateTM backup mode is “$PMTK225,9*22”.The module can exit
from AlwaysLocateTM backup mode by command “$PMTK225,0*2B” sent just after the module has been
waked up from previous backup cycle.
The positioning accuracy in AlwaysLocateTM mode will be somewhat degraded, especially in high speed.
The following picture shows the rough power consumption of L80 module in different daily scenes when
AlwaysLocateTM mode is enabled.
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Figure 9: AlwaysLocateTM Mode
Example:
The typical average consumption is about 3.5mA in AlwaysLocateTM standby mode and 3.0mA in
AlwaysLocateTM backup mode.
NOTES
1.
2.
3.
Power consumption is measured under outdoor static mode with patch antenna. Using external
active antenna will increase the power consumption.
The same as periodic backup mode, AlwaysLocateTM backup mode also needs the external switch
circuit to support, please refer to chapter 3.4.3.
Before entering into periodic backup mode, please ensure the GPS_EN signal is low and power
supply for V_BCKP is alive.
3.5. Reset
L80 module can be restarted by driving the RESET to a low level voltage for a certain time and then
releasing it. This operation will reset the digital part of the GPS receiver. Note that Non-Volatile Backup
RAM content is not cleared and thus fast TTFF is possible. An OC driver circuit shown as below is
recommended to control the RESET.
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RESET
4.7K
Input pulse
47K
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Figure 10: Reference Reset Circuit Using OC Circuit
The restart timing of L80 has been illustrated bellow.
Pulldown
> 10ms
> 650us
VCC
VIH >2.0V
RESET
UART
VIL<0.8V
Invalid
Valid
Invalid
Valid
Figure 11: Restart Timing
3.6. UART Interface
The module provides one universal asynchronous receiver & transmitter serial port. The module is
designed as a DCE (Data Communication Equipment), following the traditional DCE-DTE (Data Terminal
Equipment) connection. The module and the client (DTE) are connected through the following signals
shown as following figure. It supports data baud-rate from 4800bps to 115200bps.
UART port:
 TXD1: Send data to the RXD signal line of DTE.
 RXD1: Receive data from the TXD signal line of DTE.
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Module(DCE)
Customer(DTE)
UART port
TXD1
TXD
RXD1
RXD
GND
GND
Figure 12: Connection of Serial Interfaces
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This UART port has the following features:




UART port can be used for firmware upgrade, NMEA output and PMTK proprietary commands input.
The default output NMEA type setting is RMC, VTG, GGA, GSA, GSV, GLL and GPTXT(MTK
proprietary protocol).
UART port supports the following data rates:
4800, 9600, 14400, 19200, 38400, 57600, 115200.
The default setting is 9600bps, 8 bits, no parity bit, 1 stop bit.
Hardware flow control and synchronous operation are not supported.
The UART port does not support the RS-232 level but only CMOS level. If the module’s UART port is
connected to the UART port of a computer, it is necessary to add a level shift circuit between the module
and the computer. Please refer to the following figure.
SP3238
28
25
1
3
TXD1
Module
3.3V
V+
C1-
GND
C2+
VCC
C2-
V-
24
23
22
19
T1IN
T2IN
T3IN
T4IN
17
T5IN
16
21
20
18
RXD1
C1+
13
/R1OUT
R1OUT
R2OUT
R3OUT
T4OUT
T2OUT
T3OUT
T1OUT
T5OUT
R1IN
R2IN
R3IN
27
2
26
3.3V
4
10
6
7
5
12
8
9
11
ONLINE
15
/STATUS
14
/SHUTDOWN
6
7
8
9
To PC serial port
1
2
3
4
5
GND
Figure 13: RS-232 Level Shift Circuit
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3.7. EASY Technology
EASY technology works as embedded software which can accelerate TTFF by predicting satellite
navigation messages from received ephemeris. The GPS engine will calculate and predict orbit
information automatically up to 3 days after first receiving the broadcast ephemeris, and saving the
predicted information into the internal memory. GPS engine will use this information for positioning if no
enough information from satellites, so the function will be helpful for positioning and TTFF improvement.
The EASY function can reduce TTFF to 5s for warm start. In this case, RTC domain should be valid. In
order to gain enough broadcast ephemeris information from GPS satellites, the GPS module should
receive the information for at least 5 minutes in a good signal condition after fixing the position.
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EASY function is enabled by default. The command “$PMTK869,1,0*34” can be used to disable EASY.
For more details, please refer to the document [2].
3.8. Multi-tone AIC
L80 module provides an advanced technology called multi-tone AIC (Active Interference Cancellation) to
reject RF interference which comes from other active components on the main board.
Up to 12 multi-tone AIC embedded in the module can provide effective narrow-band interference and
jamming elimination. The GPS signal could be recovered from the jammed signal, which can ensure
better navigation quality. AIC is enabled by default, closing it will save about 1mA @VCC=3.3V
consumption. The following commands can be used to set AIC.
Enable AIC function: “$PMTK 286,1*23”.
Disable AIC function: “$PMTK 286,0*22”.
3.9. LOCUS
L80 module supports the embedded logger function called LOCUS. It can log position information to the
internal flash memory automatically when this function is enabled by sending PMTK command
“$PMTK185, 0*22”. Due to this function, the host can go to sleep to save power consumption and do not
need to receive the NMEA information all the time. The module can provide a log capacity of more than 16
hours.
The detail procedures of this function are illustrated bellow:



The module has fixed the position (only 3D_fixed is available);
Sending PMTK command “$PMTK184,1*22” to erase internal flash;
Sending PMTK command “$PMTK185,0*22” to start log;
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


Module logs the basic information (UTC time, latitude, longitude and height) every 15 seconds to
internal flash memory;
Stop logging the information by sending “$PMTK185,1*23”;
Host can get the data from the module via UART by sending“$PMTK622,1*29”.
The raw data which host gets has to be parsed via LOCUS parser code provided by Quectel. For more
details, please contact Quectel’s technical support team.
3.10. Antenna Advisor
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Antenna Advisor is design to detect and notify the different external active antenna statuses including
external active antenna detection circuit, external active antenna connection and external active antenna
shortage. The detections and notifications of external active antenna are listed in the following table.
Table 7: Status of the Antenna
Status of the Antenna
EXT/Patch
NMEA Message
External active antenna is not inserted
Patch
OPEN
External active antenna is inserted and worked normally
EXT
OK
External active antenna is inserted but short-circuited
Patch
SHORT
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4
Antenna Interface
L80 module receives L1 band signal from GPS satellites at a nominal frequency of 1575.42MHz. The LNA
is embedded for better performance. It is an ultra slim module with embedded 15.0×15.0×4.0mm patch
antenna, in addition, L80 can also support external active antenna, and the RF signal is obtained from the
EX_ANT pin. Both internal patch signal and external active antenna signal are intelligently switched
through SPDT.
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4.1. Recommended Circuit for Antenna
4.1.1. Internal Patch Antenna
4.1.1.1. 15*15*4 Patch Antenna
The quality of the embedded GPS antenna is crucial to the overall sensitivity of the GPS system. L80
offers an on-module patch antenna. A 15.0×15.0×4.0mm high-performance patch antenna is chosen for
reducing product size. This antenna is specially designed for satellite reception applications. And it has
excellent stability and sensitivity to consistently provide high signal reception efficiency. The specification
of the antenna used by L80 is described in following table.
Table 8: Antenna Specification for L80 Module with Ground Plane 100mm×60mm
Antenna
type
Patch
antenna
Parameter
Specification
Size
15.0×15.0×4.0mm
Range of receiving
Frequency
1575.42MHz±1.023MHz
Impendence
50 Ohm
Band Width
10MHz minimum
Return Loss ≦-10dB
Frequency Temperature
Coefficient (TF)
0±20ppm/°C
-40°C-85°C
Polarization
RHCP
Right Hand Circular Polarization
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Gain at Zenith
3.4dBi typ
VSWR
1.5 max
Axial ratio
3 dB max
Centre frequency
The test result of the antenna is shown as the following figure. This embedded GPS antenna provides
good radiation efficiency, right hand circular polarization and optimized radiation pattern. The antenna is
insensitive to surroundings and has high tolerance against frequency shifts.
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Figure 14: Patch Antenna Test Result with Ground Plane 100mm×60mm
4.1.1.2. PCB Design Guide
Radiation characteristics of antenna depend on various factors, such as the size and shape of the PCB,
the dielectricconstant of components nearby. For the best performance, it is recommended to follow these
rules listed as below.
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Keep at least 10mm distance to the nearest edge of the mother board. It will be better for L80 to be placed
in the center of the mother board.
Keep enough distance between L80 antenna and tall components, the height of which is more than 6mm,
and the minimum distance (d) is 10mm.
Put L80 on the top of the main PCB, which can guarantee antenna to face to open sky and achieve good
receiving performance during operation.
Device enclosure should be made of non-metal materials especially around antenna area. The minimum
distance between antenna and enclosure is 1mm.
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It is recommended that the mother board is bigger than 80mm×40mm for the better performance. And
pour ground copper on the whole mother board.
Other antennas such as BT\WIFI\GSM should be kept minimum 10mm distance far away from the
embedded patch antenna in L80.
Integrated
chips
d
d
d
d
Other
antenna
Mother board
L80-M39
d
Metal
components
BT/WIFI/GSM
d is supposed to be greater than 10mm and no metal cover used for this area.
Figure 15: L80 Module Placement Guide
4.1.2. External Active Antenna
The following figure is a typical reference design with active antenna. In this mode, DC on the EX_ANT
pin is powered by VCC and supplies power to the external active antenna.
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Active
Antenna
15*15 Patch Antenna
0R
EX_ANT
C2 NM
C1 NM
R1
47nH
56pF
Short
Protection
Circuit
П matching circuit
SPDT
RF-Front
End
Active Antenna
Detection Circuit
Detection signal
Detection signal
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VCC
L80 Module
Figure 16: Reference Design for Active Antenna
C1, R1, C2 are reserved matching circuit for antenna impedance modification. By default, C1 and C2 are
not mounted, R1 is 0 ohm. In this mode, R1 must not be capacitance, because current should flows
through R1 to the antenna. C1 and C2 must not be inductance or resistance to avoid short.
The impedance of RF trace line in main PCB should be controlled by 50 Ohm, and the length should be
kept as short as possible.
NOTE
L80 module provides power supply for external active antenna internally. There is about 0.3V voltage drop
between VCC and external active antenna. If you want to use external active antenna, the voltage drop,
VCC voltage and external active antenna operating voltage need to be considered.
Table 9: Recommended Active antenna Specification
Antenna Type
Specification
Active antenna
Center frequency:
Band width :
VSWR:
Polarization:
Noise figure:
Gain (antenna):
Gain (embedded LNA):
Total Gain:
L80_Hardware_Design
1575.42MHz
>5MHZ
<2 (Typ.)
RHCP or Linear
<1.5dB
>-2dBi
20dB (Typ.)
>18dBi(Typ.)
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4.2. Antenna Detection and Handling Mechanism
L80 module supports automatic antenna switching function. The GPTXT sentence can be used to identify
the status of external active antenna.
If ANTSTATUS=OPEN, it means open-circuit state is dectected and the internal antenna is used at this
time.
If ANTSTATUS=OK, it means external active antenna is connected and the module will use external
active antenna.
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If ANTSTATUS=SHORT, it means short circuit state is dectected and the internal antenna is used.
NOTES
1.
2.
3.
When you use external active antenna and the “OPEN” is displayed in the GPTXT of NMEA
sentence, you have to check the connection status of external active antenna.
If the external active antenna is short-circuited, the “SHORT” will be displayed in the GPTXT of
NMEA sentence.
Because antenna short protection is enabled by default, L80 will switch to embedded patch antenna
automatically in case that external active antenna is short-circuited, which will avoid L80 from
damage. Meanwhile, you need to check the external active antenna.
Example:
“OPEN” is displayed in the GPTXT sentence as below
Figure 17: Patch Antenna Status Description in GPSTXT
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Table 10: GPTXT - Status of Antenna
GPTXT
Display
Ext Active
Antenna Status
Inner Patch
Antenna Status
Attention
OPEN
Unused
Working
You need to check the external active antenna
status if the active antenna is using.
OK
Working
Unused
SHORT
Short
Working
NOTE
Please check the external active antenna
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L80 module only supports external active antenna and cannot use external passive antenna.
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5
Electrical, Reliability and Radio
Characteristics
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5.1. Absolute Maximum Ratings
Absolute maximum ratings for power supply and voltage on digital pins of the module are listed in the
following table.
Table 11: Absolute Maximum Ratings
Parameter
Min
Max
Unit
Power supply voltage(VCC)
-0.3
5.0
V
Backup battery voltage (V_BCKP)
-0.3
5.0
V
Input voltage at digital pins
-0.3
3.6
V
0
dBm
125
°C
Input power at EX_ANT
Storage temperature
NOTE
-45
Stressing the device beyond the “Absolute Maximum Ratings” may cause permanent damage. These are
stress ratings only. The product is not protected against over voltage or reversed voltage. If necessary,
voltage spikes exceeding the power supply voltage specification, given in table above, must be limited to
values within the specified boundaries by using appropriate protection diodes.
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5.2. Operating Conditions
Table 12: The Module Power Supply Ratings
Parameter
VCC
IVCCP
V_BCKP
TOPR
NOTE
Description
Conditions
Min
Typ
Max
Unit
Supply voltage
Voltage must stay within
the min/max values,
including voltage drop,
ripple, and spikes.
2.8
3.3
4.3
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Peak supply current
VCC=3.3V
100
mA
Backup voltage supply
1.5
3.3
4.3
V
Normal Operating
temperature
-40
25
85
℃
1. The figure IVCCP can be used to determine the maximum current capability of power supply.
2. Operation beyond the "Operating Conditions" is not recommended and extended exposure beyond
the "Operating Conditions" may affect the device’s reliability.
5.3. Current Consumption
The values for current consumption are shown in the following table.
Table 13: The Module Current Consumption
Parameter
Conditions
Min
Typ
Max
Unit
IVCC@Acquisition
VCC=V_BCKP=3.3V
25
mA
IVCC@Tracking
VCC= V_BCKP=3.3V
20
mA
IVCC@Standby
VCC= V_BCKP=3.3V
1.0
mA
IBCKP@Backup
V_BCKP=3.3V
7
uA
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NOTE
The tracking current is tested in the following conditions:
 For Cold Start, 10 minutes after First Fix.
 For Hot Start, 15 seconds after First Fix.
5.4. Electro-static Discharge
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L80 module is an ESD sensitive device. ESD protection precautions should still be emphasized. Proper
ESD handing and packaging procedures must be applied throughout the processing, handing and
operation of any application.
The ESD bearing capability of the module is listed in the following table. Note that you should add ESD
components to module pins in the particular applications.
Table 14: The ESD Endurance Table (Temperature: 25℃, Humidity: 45 %)
Pin
VCC
UART
Others
Contact Discharge
Air Discharge
±5KV
±10KV
±3KV
±6KV
±2KV
±4KV
5.5. Reliability Test
Table 15: Reliability Test
Test item
Condition
Standard
Thermal shock
-30°C...+80°C, 144 cycles
GB/T 2423.22-2002 Test Na
IEC 68-2-14 Na
Damp heat,
cyclic
+55°C; >90% Rh 6 cycles for 144 hours
IEC 68-2-30 Db Test
Vibration shock
5~20Hz,0.96m2/s3;20~500Hz,0.96m2/s3-3dB/oct,
1hour/axis; no function
2423.13-1997 Test Fdb
IEC 68-2-36 Fdb Test
Heat test
85°C, 2 hours, Operational
GB/T 2423.1-2001 Ab
IEC 68-2-1 Test
Cold test
-40°C, 2 hours, Operational
GB/T 2423.1-2001 Ab
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IEC 68-2-1 Test
Heat soak
90°C, 72 hours, Non-Operational
GB/T 2423.2-2001 Bb
IEC 68-2-2 Test B
Cold soak
-45°C, 72 hours, Non-Operational
GB/T 2423.1-2001 A
IEC 68-2-1 Test
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6
Mechanics
This chapter describes the mechanical dimensions of the module.
6.1. Mechanical View of the Module
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Figure 18: Mechanical View(Unit: mm)
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6.2. Bottom Dimension and Recommended Footprint
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Figure 19: Bottom Dimension(Unit: mm)
7
6
12
1
Figure 20: Footprint of Recommendation(Unit: mm)
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NOTE
For easy maintenance, please keep a distance of no less than 3mm between the module and other
components in host board.
6.3. Top View of the Module
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Figure 21: Top View of the Module
6.4. Bottom View of the Module
6
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12
Figure 22: Bottom View of the Module
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7
Manufacturing
7.1. Assembly and Soldering
L80 module is intended for SMT assembly and soldering in a Pb-free reflow process on the top side of the
PCB. It is suggested that the minimum height of solder paste stencil is 100um to ensure sufficient solder
volume. Pad openings of paste mask can be increased to ensure proper soldering and solder wetting over
pads. It is suggested that peak reflow temperature is 235~245ºC (for SnAg3.0Cu0.5 alloy). Absolute max
reflow temperature is 260ºC. To avoid damage to the module when it is repeatedly heated, it is suggested
that the module should be mounted after the first panel has been reflowed. The following picture is the
actual diagram which we have operated.
℃
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Preheat
250
Heating
Cooling
Liquids Temperature
217
200
200℃
40s~60s
160℃
150
70s~120s
100
Between 1~3℃/S
50
0
50
100
150
200
250
300
s
Time(s)
Figure 23: Ramp-soak-spike-reflow of Furnace Temperature
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7.2. Moisture Sensitivity
L80 module is sensitivity to moisture absorption. To prevent L80 from permanent damage during reflow
soldering, baking before reflow is required in following cases:


Humidity indicator card: At least one circular indicator is no longer blue
The seal is opened and the module is exposed to excessive humidity.
L80 should be baked for 192 hours at temperature 40℃+5℃/-0℃ and <5% RH in low-temperature
containers, or 24 hours at temperature 125℃±5℃ in high-temperature containers. Care should be taken
that plastic tray is not heat resistant. L80 should be taken out before preheating, otherwise, the tray
maybe damaged by high-temperature heating.
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7.3. ESD Safe
L80 module is an ESD sensitive device and should be handled carefully.
7.4. Tape and Reel
Unit:mm
Quantity per reel:250pcs
Lengh per reel:6.5m
Figure 24: Tape and Reel Specification
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Table 16: Tray Packing
Model Name
L80
MOQ for MP
Minimum Package:250pcs
Minimum Package x4=1000pcs
250pcs
Size: 370mm×350mm×56mm
N.W: 1.5kg
G.W: 2.25kg
Size: 380mm×250mm×365mm
N.W: 6.1kg
G.W:9.4kg
7.5. Ordering Information
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Table 17: Ordering Information
Model Name
Ordering Code
L80
L80-M39
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8
Appendix Reference
Table 18: Related Documents
SN
[1]
[2]
[3]
Document name
Remark
L80_EVB _User Guide
L80 EVB User Guide
L80_GPS_Protocol_Specification
L80 GPS Protocol Specification
L80_Reference_Design
L80 Reference Design
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Table 19: Terms and Abbreviations
Abbreviation
Description
AGPS
Assisted GPS
AIC
CEP
DGPS
EASY
EGNOS
EPO
ESD
GPS
Active Interference Cancellation
Circular Error Probable
Differential GPS
Embedded Assist System
European Geostationary Navigation Overlay Service
Extended Prediction Orbit
Electrostatic Discharge
Global Positioning System
GNSS
Global Navigation Satellite System
GGA
GPS Fix Data
GLL
Geographic Position – Latitude/Longitude
GLONASS
Global Navigation Satellite System
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GSA
GNSS DOP and Active Satellites
GSV
GNSS Satellites in View
HDOP
Horizontal Dilution of Precision
I/O
Input /Output
Kbps
Kilo Bits Per Second
LNA
Low Noise Amplifier
MSAS
MOQ
NMEA
PDOP
PMTK
PPS
PRN
QZSS
RHCP
RMC
SBAS
SAW
TTFF
UART
VDOP
VTG
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Multi-Functional Satellite Augmentation System
Minimum Order Quantity
National Marine Electronics Association
Position Dilution of Precision
MTK Proprietary Protocol
Pulse Per Second
Pseudo Random Noise Code
Quasi-Zenith Satellite System
Right Hand Circular Polarization
Recommended Minimum Specific GNSS Data
Satellite-based Augmentation System
Surface Acoustic Wave
Time To First Fix
Universal Asynchronous Receiver & Transmitter
Vertical Dilution of Precision
Course over Ground and Ground Speed, Horizontal Course and Horizontal
Velocity
WAAS
Wide Area Augmentation System
Inom
Nominal Current
Imax
Maximum Load Current
Vmax
Maximum Voltage Value
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Vnom
Nominal Voltage Value
Vmin
Minimum Voltage Value
VIHmax
Maximum Input High Level Voltage Value
VIHmin
Minimum Input High Level Voltage Value
VILmax
Maximum Input Low Level Voltage Value
VILmin
Minimum Input Low Level Voltage Value
VImax
VImin
VOHmax
VOHmin
VOLmax
VOLmin
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Absolute Maximum Input Voltage Value
Absolute Minimum Input Voltage Value
Maximum Output High Level Voltage Value
Minimum Output High Level Voltage Value
Maximum Output Low Level Voltage Value
Minimum Output Low Level Voltage Value
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