L80 Hardware Design
GPS Module Series
Rev. L80_Hardware_Design_V1.1
Date: 2013-08-10
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About the document
History
Revision
Date
Author
Description
V1.0
2013-07-25
Tony GAO
Initial
V1.1
2013-08-10
Tony GAO
1. Modified the voltage range of VCC pin.
2. Added AADET_N pin in Figure 1 Block
Diagram, and the description of it in Table 3.
3. Modified the description about power supply
in chapter 3.3.
4. Optimized the mechanical dimensions about
the height in Figure 18.
5. Modified the structure of chapter 4.
6. Added content in chapter 4.3 about how to
judge the antenna status via AADET_N pin.
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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 ...................................................................................................................... 11
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 ................................................................................................................ 17
3.4.2. Standby Mode .............................................................................................................. 18
3.4.3. Backup Mode ............................................................................................................... 18
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 Supervisor ................................................................................................................. 26
4 Antenna Interface ............................................................................................................................. 27
4.1. Internal Patch Antenna ............................................................................................................. 27
4.1.1. 15*15*4 Patch Antenna ................................................................................................ 27
4.1.2. PCB Design Guide ....................................................................................................... 28
4.2. External Active Antenna ........................................................................................................... 29
4.3. Antenna Status Indicator .......................................................................................................... 30
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
5.5. Reliability Test .......................................................................................................................... 35
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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 MODULE SUPPORTS ....................................................................................... 11
TABLE 3: PIN DESCRIPTION ........................................................................................................................... 12
TABLE 4: MODULE STATES SWITCH ............................................................................................................. 16
TABLE 5: DEFAULT CONFIGURATIONS ......................................................................................................... 17
TABLE 6: PMTK COMMAND FORMAT ............................................................................................................ 20
TABLE 7: STATUS OF THE ANTENNA ............................................................................................................. 26
TABLE 8: ANTENNA SPECIFICATION FOR L80 MODULE WITH GROUND PLANE 100MM×60MM............ 27
TABLE 9: RECOMMENDED ACTIVE ANTENNA SPECIFICATION ................................................................. 30
TABLE 10: GPTXT - STATUS OF ANTENNA .................................................................................................... 31
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 .......................................... 16
FIGURE 6: THE EXTERNAL SWITCH CIRCUIT FOR TIMER ......................................................................... 18
FIGURE 7: SEIKO MS920SE CHARGE AND DISCHARGE CHARACTERISTICS ......................................... 19
FIGURE 8: PERIODIC MODE ........................................................................................................................... 21
FIGURE 9: ALWAYSLOCATETM 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
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, AlwaysLocateTM and
Antenna Supervisor. 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: 3.0V ~ 4.3V typical : 3.3V
Power Consumption
Acquisition 25mA@ VCC=V_BCKP=3.3V
Tracking 20mA@ VCC= V_BCKP =3.3V
Standby 1.0mA @ VCC= V_BCKP =3.3V
Backup 7uA@ V_BCKP=3.3V
Receiver Type
GPS L1 1575.42MHz C/A Code
66 search channels, 22 simultaneous tracking channels
Sensitivity
Acquisition -148dBm
Re-acquisition -160dBm
Tracking -165dBm
TTFF (EASY enabled)
Cold Start 15s typ.@-130dBm
Warm Start 5s typ.@-130dBm
Hot Start 1s typ. @-130dBm
TTFF (EASY disabled)
Cold Start (Autonomous) 35s typ.@-130dBm
Warm Start (Autonomous) 30s typ.@-130dBm
Hot Start (Autonomous) 1s typ.@-130dBm
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
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
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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
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.
Figure 1: Block Diagram
NOTES
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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.
For more details, please refer to the document [1].
2.5. The Protocols Module Supports
Table 2: The Protocols Module Supports
Please refer to document [2] about NMEA standard protocol and MTK proprietary protocol.
Protocol
Type
NMEA
Output, ASCII, 0183, 3.01
PMTK
Input, MTK proprietary protocol
NOTE
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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.
3.1. Pin Assignment
2
3
4
5
GND
1
TXD1
6
11
10
9
8
12
71PPS
AADET_N
TIMER
NC
GND
V_BCKP
VCC
(Top View)
L80
RESET
EX_ANT
RXD1
Figure 2: Pin Assignment
3.2. Pin Definition
Table 3: Pin Description
Power supply
Pin Name
Pin No.
I/O
Description
DC Characteristics
Comment
VCC
4
I
Main power
supply
Vmax= 4.3V
Vmin=3.0V
Vnom=3.3V
Supply current of no less
than 100mA.
V_BCKP
5
I
Backup power
supply
Vmax=4.3V
Vmin=1.5V
Vnom=3.3V
Supply power for RTC
domain. The V_BCKP pin
can be directly supplied
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power by battery or
connect it to VCC.
Reset
Pin Name
Pin No.
I/O
Description
DC Characteristics
Comment
RESET
10
I
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.
UART port
Pin Name
Pin No.
I/O
Description
DC Characteristics
Comment
RXD1
1
I
Receive data
VILmin=-0.3V
VILmax=0.8V
VIHmin=2.0V
VIHmax=3.6V
TXD1
2
O
Transmit data
VOLmin=-0.3V
VOLmax=0.4V
VOHmin=2.4V
VOHmax=3.1V
RF interface
Pin Name
Pin No.
I/O
Description
DC Characteristics
Comment
EX_ANT
11
I
external active
antenna RF
input
Characteristic
impedance of 50Ω
If unused, keep this pin
open.
Other interfaces
Pin Name
Pin No.
I/O
Description
DC Characteristics
Comment
1PPS
6
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.
TIMER
7
O
An open drain
output signal
can be used to
control GPS
module main
power on/off
VOLmin=-0.3V
VOLmax=0.4V
VOHmin=1.1V
VOHmax= 3.1V
It belongs to RTC domain.
If unused, keep this pin
open or connect to Ground
externally.
AADET_N
8
I/O
Active antenna
detection
VOLmax=0.7V
VOHmin=1.3V
If unused, keep this pin
open. Refer to chapter
4.3.
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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.
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 in
red in the following figure belongs to RTC domain and can be used to control the power switch on/off.
ARM
RTC
Power
Logic
Circuit
PMU VCC
V_BCKP
RTC
Power Switch
4
5
7TIMER
L80_Module
Figure 3: Internal Power Construction
Power supply solutions for L80 module are listed as the following.
The simplest power circuit for L80 module is 3.3V power source connected to VCC pin and V_BCKP pin
of the module directly. In this case, once you powered on the module, the full cold start will be
implemented.
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10uF 100nF L80_Module
3.3V
4
5
VCC
V_BCKP
100nF
C1 C2
C3
Figure 4: Reference Circuit for Power Supply
If your power supply circuit adopts the design mentioned above, L80 module does not support EASY
technology and backup mode and other modes related with it, e.g. AlwaysLocateTM backup mode.
The other way is V_BCKP is fed through a backup battery directly. The module will enter into backup
mode when power source (3.3V) is cut off. Furthermore, it is necessary to add an external charging circuit
for rechargeable battery. The detailed schematic (mount R2 with 0R to replace Power switch) is shown as
below. Note that the capacity of backup battery should be large enough to maintain V_BCKP valid as
there is no charge source when power source (3.3V) is cut off. MS621FE FL11E from Seiko is
recommended. The consumption of V_BCKP is as low as 7uA in backup mode.
You can also apply a power switch circuit to replace R2 when it matches with TIMER pin. In this way, the
module will not only support backup mode but also support periodic backup mode and AlwaysLocateTM
backup mode. The schematic with power supply circuit is shown as below. As power source (3.3V) is
always valid and charge the battery continuously. The capacity of the battery can be small. The detail
schematic for power switch circuit is shown in Figure 6.
For more details about backup mode, periodic backup mode and AlwaysLocateTM backup mode, please
refer to the related chapters.
NOTE
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Power Switch
R2 NC
3.3V
Charging
Circuit
Rechargeable
Battery
4
5
VCC
V_ BCKP
10uF
R1
1K
TIMER
C1 C2
C3 C4
D1
L80_Module
100nF
4.7uF 100nF
Figure 5: Reference Charging Circuit for Chargeable Battery
VCC does not supply power for RTC domain in L80 module, so the V_BCKP pin must be powered
externally. Furthermore, it is strongly recommended to supply power to V_BCKP through a backup
battery, which can ensure L80 module supports EASY technology and improves TTFF after next restart.
For details about TTFF, please refer to chapter 2.2.
3.4. Operating Modes
The table below briefly illustrates the relationship among different operating modes of L80 module.
Table 4: Module States Switch
Current
Mode
Next Mode
Backup
Standby
Full on
Periodic
AlwaysLocateTM
Backup
N/A
N/A
Refer to
chapter 3.4.3
N/A
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
NOTE
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Always
LocateTM
N/A
N/A
Refer to
chapter 3.4.5
N/A
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
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
Comment
Baud rate
9600bps
Protocol
NMEA
RMC, VTG, GGA, GSA, GSV, GLL and
GPTXT（MTK proprietary protocol）
Update rate
1Hz
SBAS
Enable
AIC
Enable
LOCUS
Disable
EASY
Enable
EASY will be disabled automatically when update rate
exceeds 1Hz.
NOTE
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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 “$PMTK161,0*28” will make L80 module enter into standby mode. Sending any
data via UART can wake the module up. When the module exits from standby mode, it will use all internal
aiding information like GPS time, Ephemeris, Last Position etc, resulting to a fastest possible TTFF in
either Hot or Warm start. The typical standby current consumption in this way is about 1mA @VCC=3.3V.
When the external active antenna is used, an additional 11mA will be consumed because the VCC still
supply power for external active antenna in standby mode.
3.4.3. Backup Mode
Backup mode is a lower power mode than standby mode. In this mode, only the backup supply V_BCKP
is powered on while the main supply VCC is switched off by host or the TIMER signal of L80. In order to
enter into backup mode autonomously via the TIMER pin, an external switch circuit is necessary. The
following figure has shown a typical reference design about the switch circuit for TIMER.
VIN VOUT
EN GND
LDO_3.3V VCC_3.3V
TIMER
GPS_EN
R1
47K
D2
D1
Power Switch
ADP191
U1
Figure 6: The External Switch Circuit for TIMER
1. U1 is an integrated power switch component. The part number ADP191 is recommended. U1 also
can be replaced by discrete components, please refer to document [3] for more details.
2. TIMER pin also can be used to control the EN pin of a LDO.
NOTES
NOTE
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3. TIMER and GPS_EN signals form an “OR” logic via the Schottky diodes D1 and D2. GPS_EN is a
GPIO signal coming from the host.
4. TIMER is an open drain output signal. When TIMER pin is used, please pull it high by using an
external resistor. R1 is the pull-up resistor for TIMER signal.
Keeping GPS_EN signal low and sending PMTK command“$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 Semiconductor
is recommended to be used here for its low voltage drop.
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:
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Table 6: PMTK Command Format
Format:
$PMTK225,<Type>,<Run_time>,<Sleep_time>,<2nd_run_time>,<2nd_sleep_time>*<checksum><
CR><LF>
Parameter
Format
Description
Type
Decimal
Type=1 for Periodic Backup Mode
Type=2 for Periodic Standby Mode
Run_time
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
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 enter full on mode from periodic standby
mode.
Sending “$PMTK225,0*2B” just in Run_time or 2nd_run_time can make the module to enter full on
mode from periodic backup mode.
1. The precondition is external switch circuit supports periodic backup mode. For details, please refer to
chapter 3.4.3.
2. 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_time and 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
NOTES
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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)
Power
Run_time Run_time
Sleep_time Sleep_time
2nd_run_time
2nd_sleep_time
Run_time Run_time
Sleep_time Sleep_time
Full on 2nd_run_time
2nd_sleep_time
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 can switch between full on mode and backup mode automatically. 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
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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.
Figure 9: AlwaysLocateTM Mode
Example:
The typical average consumption is about 3.5mA in AlwaysLocateTM standby mode and 3.0mA in
AlwaysLocateTM backup mode.
1. Power consumption is measured under outdoor static mode with patch antenna. Using external
active antenna will increase the power consumption.
2. 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.
NOTES
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4.7K
47K
RESET
Input pulse
Figure 10: Reference Reset Circuit Using OC Circuit
The restart timing of L80 has been illustrated bellow.
VIL<0.8V
VIH >2.0V
Pulldown
> 10ms
RESET
UART Valid ValidInvalidInvalid
VCC > 650us
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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Customer(DTE)
TXD
RXD
GND
Module(DCE)
UART port
TXD1
RXD1
GND
Figure 12: Connection of Serial Interfaces
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
3.3V
T5OUT
/SHUTDOWN
V+
GND
V-
VCC
T4OUT
T2OUT
T3OUT
T1OUT
R3IN
R2IN
R1IN
/STATUS
3.3V ONLINE
R1OUT
R2OUT
R3OUT
/R1OUT
T5IN
T4IN
T3IN
T2IN
T1IN
C2+
C2-
C1-
C1+
Module
RXD1
TXD1
9
8
7
6
5
4
3
2
1
15
14
8
9
11
12
5
7
6
10
4
26
2
27
13
18
20
21
16
17
19
22
23
24
3
1
25
28
GND
To PC serial port
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 get 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.
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 as 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 Supervisor
Antenna Supervisor is designed to detect different external active antenna status including external active
antenna connection, open circuit for antenna and antenna shortage and then notify the module. 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 compact 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.
4.1. Internal Patch Antenna
4.1.1. 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
Parameter
Specification
Notes
Patch
antenna
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
Gain at Zenith
3.4dBi typ
Centre frequency
VSWR
1.5 max
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Axial ratio
3 dB max
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.
Figure 14: Patch Antenna Test Result with Ground Plane 100mm×60mm
4.1.2. 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.
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.
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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.
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.
Mother board
Integrated
chips
Metal
components
Other
antenna
d
d
d
d
d is supposed to be greater than 10mm and no metal cover used for this area.
d
L80-M39
BT/WIFI/GSM
Figure 15: L80 Module Placement Guide
4.2. 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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П matching circuit
L80_Module
EX_ANT
Active
Antenna
R1
0R
C1 NM
C2 NM
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, as current will stream through R1 to
the active antenna. C1 and C2 must not be inductance or resistance to avoid short circuit.
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.
Table 9: Recommended Active Antenna Specification
4.3. Antenna Status Indicator
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 external active antenna is not connected or has poor contact with
antenna feeding point and the internal antenna is used.
If ANTSTATUS=OK, it means external active antenna is connected and the module will use external
active antenna.
Antenna Type
Specification
Active antenna
Center frequency: 1575.42MHz
Band width : >5MHZ
VSWR: <2 (Typ.)
Polarization: RHCP or Linear
Noise figure: <1.5dB
Gain (antenna): >-2dBi
Gain (embedded LNA): 20dB (Typ.)
Total Gain: >18dBi(Typ.)
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If ANTSTATUS=SHORT, it means active antenna is short circuited and the internal patch antenna will be
used automatically.
1. 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.
2. If the external active antenna is short-circuited, the “SHORT” will be displayed in the GPTXT of
NMEA sentence.
3. 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
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
Please check the external active antenna
NOTES
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The pin “AADET_N” also can be used to indicate the status of active antenna. When active antenna is not
connected to EX_ANT or has poor contact with antenna feeding point, AADET_N will keep a high level to
indicate the active antenna absent. AADET_N will change to a low level when active antenna is
connected well.
Active antenna is ONLY available when the voltage of AADET_N is less than or equal to 0.7 V.
NOTE
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5 Electrical, Reliability and Radio
Characteristics
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
Input power at EX_ANT
0
dBm
Storage temperature
-45
125
°C
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.
NOTE
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5.2. Operating Conditions
Table 12: The Module Power Supply Ratings
Parameter
Description
Conditions
Min
Typ
Max
Unit
VCC
Supply voltage
Voltage must stay within
the min/max values,
including voltage drop,
ripple, and spikes.
3.0
3.3
4.3
V
IVCCP
Peak supply current
VCC=3.3V
100
mA
V_BCKP
Backup voltage supply
1.5
3.3
4.3
V
TOPR
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
NOTE
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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
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
Contact Discharge
Air Discharge
EX_ANT
±5KV
±10KV
Patch antenna
±5KV
±10KV
VCC
±5KV
±10KV
UART
±3KV
±6KV
Others
±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
NOTE
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IEC 68-2-1 Test
Cold test
-40° C, 2 hours, Operational
GB/T 2423.1-2001 Ab
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
Figure 18: Mechanical View（Unit: mm）
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6.2. Bottom Dimension and Recommended Footprint
Figure 19: Bottom Dimension（Unit: mm）
Figure 20: Footprint of Recommendation（Unit: mm）
1
6
7
12
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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
Figure 21: Top View of the Module
6.4. Bottom View of the Module
Figure 22: Bottom View of the Module
NOTE
6
12
7
1
1
6
7
12
L80-M39
►
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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.
Time(s)
50 100 150 200 250 300
50
100
150
200
250
160℃
200℃
217
0
70s~120s
40s~60s
Between 1~3℃/S
Preheat Heating Cooling
℃
s
Liquids
Temperature
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.
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
MOQ for MP
Minimum Package:250pcs
Minimum Package x4=1000pcs
L80
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
Table 17: Ordering Information
Model Name
Ordering Code
L80
L80-M39
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8 Appendix Reference
Table 18: Related Documents
SN
Document name
Remark
[1]
L80_EVB _User Guide
L80 EVB User Guide
[2]
L80_GPS_Protocol_Specification
L80 GPS Protocol Specification
[3]
L80_Reference_Design
L80 Reference Design
Table 19: Terms and Abbreviations
Abbreviation
Description
AGPS
Assisted GPS
AIC
Active Interference Cancellation
CEP
Circular Error Probable
DGPS
Differential GPS
EASY
Embedded Assist System
EGNOS
European Geostationary Navigation Overlay Service
EPO
Extended Prediction Orbit
ESD
Electrostatic Discharge
GPS
Global Positioning System
GNSS
Global Navigation Satellite System
GGA
GPS Fix Data
GLL
Geographic Position – Latitude/Longitude
GLONASS
Global Navigation Satellite System
Quectel
Confidential
GPS Module
L80 Hardware Design
L80_Hardware_Design Confidential / Released 44 / 45
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
Multi-Functional Satellite Augmentation System
MOQ
Minimum Order Quantity
NMEA
National Marine Electronics Association
PDOP
Position Dilution of Precision
PMTK
MTK Proprietary Protocol
PPS
Pulse Per Second
PRN
Pseudo Random Noise Code
QZSS
Quasi-Zenith Satellite System
RHCP
Right Hand Circular Polarization
RMC
Recommended Minimum Specific GNSS Data
SBAS
Satellite-based Augmentation System
SAW
Surface Acoustic Wave
SPDT
Single-Pole Double-Throw
TTFF
Time To First Fix
UART
Universal Asynchronous Receiver & Transmitter
VDOP
Vertical Dilution of Precision
VTG
Course over Ground and Ground Speed, Horizontal Course and Horizontal
Velocity
WAAS
Wide Area Augmentation System
Inom
Nominal Current
Imax
Maximum Load Current
Quectel
Confidential
GPS Module
L80 Hardware Design
L80_Hardware_Design Confidential / Released 45 / 45
Vmax
Maximum Voltage Value
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
Absolute Maximum Input Voltage Value
VImin
Absolute Minimum Input Voltage Value
VOHmax
Maximum Output High Level Voltage Value
VOHmin
Minimum Output High Level Voltage Value
VOLmax
Maximum Output Low Level Voltage Value
VOLmin
Minimum Output Low Level Voltage Value
Quectel
Confidential