Quectel L70 GPS module Hardware Design
Quectel L80 EVB is a development board that enables rapid prototyping and evaluation of Quectel's L80 module, a high-performance LTE Cat M1/NB1 module supporting multiple frequency bands and a variety of applications, such as smart metering, asset tracking, and remote monitoring. With an ultra-compact size and low power consumption, the L80 EVB offers reliable connectivity and a rich set of interfaces, including UART, GPIO, and I2C, making it ideal for IoT developers and system integrators.
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L70
Quectel GPS Engine
Hardware Design
L70_HD_V1.0
L70 Hardware Design
Document Title L70 Hardware Design
1.0 Revision
Date 2012-07-13
Released Status
Document Control ID L70_HD_V1.0
General Notes
Quectel offers this information as a service to its customers, to support application and engineering efforts that use the products designed by Quectel. The information provided is based upon requirements specifically provided for customers of Quectel. Quectel has not undertaken any independent search for additional information, relevant to any information that may be in the customer’s possession. Furthermore, system validation of this product designed by Quectel within a larger electronic system remains the responsibility of the customer or the customer’s system integrator. All specifications supplied herein are subject to change.
Copyright this document, distribution to others, and communication of the contents thereof, are forbidden without permission
.
Offenders are liable to the payment of damages. All rights are reserved in the event of a patent grant or registration of a utility model or design. All specification supplied herein are subject to change without notice at any time.
Copyright © Quectel Wireless Solutions Co., Ltd. 2012
Confidential
L70_HD_V1.0 - 1 -
L70 Hardware Design
Contents
mode ............................................................................................ 11
L70_HD_V1.0 - 2 -
L70 Hardware Design
Quectel
Confidential
L70_HD_V1.0 - 3 -
L70 Hardware Design
Table Index
TABLE 7: THE WAYS OF ENTERING AND EXITING FROM STANDBY MODE ......................... 18
TABLE 14: THE MODULE CURRENT CONSUMPTION (PASSIVE ANTENNA) .......................... 28
TABLE 15: THE ESD ENDURANCE TABLE (TEMPERATURE: 25℃, HUMIDITY: 45 %) ........... 28
Quectel
Confidential
L70_HD_V1.0 - 4 -
L70 Hardware Design
Figure Index
FIGURE 6: RTC SUPPLY FROM NON-CHARGEABLE BATTERY OR CAPACITOR .................... 19
FIGURE 7: REFERENCE CHARGING CIRCUIT FOR CHARGEABLE BATTERY ........................ 19
FIGURE 14: REFERENCE DESIGN FOR PASSIVE ANTENNA WITH LNA ................................... 25
FIGURE 15: REFERENCE DESIGN FOR ACTIVE ANTENNA WITHOUT LNA ............................ 26
FIGURE 16: REFERENCE DESIGN FOR ACTIVE ANTENNA WITH LNA .................................... 26
FIGURE 19: FOOTPRINT OF RECOMMENDATION（UNIT:MM） ............................................... 31
Confidential
L70_HD_V1.0 - 5 -
L70 Hardware Design
0. Revision history
Revision Date
1.0 2012-07-10
Author
King HAO
Description of change
Initial
Quectel
Confidential
L70_HD_V1.0 - 6 -
L70 Hardware Design
1. Introduction
This document defines and specifies L70 GPS module. It describes L70 hardware interface and its external application reference circuits, mechanical size and air interface.
This document can help customer quickly understand the interface specifications, electrical and mechanical details of L70 module. With the help of this document and other related documents, customer can use L70 module to design and set up applications easily.
1.1. Related documents
Table 1: Related documents
SN Document name
[1] L70_EVB _UGD
[2] L70_GPS_Protocol
[3] L70_Reference_Design
Remark
L70 EVB User Guide
L70 GPS Protocol Specification
L70 Reference Design
GGA
GLL
GSA
GSV
HDOP
IC
AIC
CEP
1.2. Terms and abbreviations
AGPS
Quectel
Active Interference Cancellation
Circular Error Probable
GPS
GNSS
DGPS
EASY
EGNOS
EMC
EPO
ESD
Differential GPS
Embedded Assist System
Confidential
Global Positioning System
Global Navigation Satellite System
GPS Fix Data
Geographic Position – Latitude/Longitude
GNSS DOP and Active Satellites
GNSS Satellites in View
Horizontal Dilution of Precision
Integrated Circuit
L70_HD_V1.0 - 7 -
L70 Hardware Design
QZSS
RHCP
RMC
RTCM
SBAS
SAW
TTFF
UART
I/O
Kbps
LNA
MSAS
NMEA
PDOP
PMTK
PPS
PRN
Input /Output
Kilo Bits Per Second
Low Noise Amplifier
Multi-Functional Satellite Augmentation System
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
Radio Technical Commission for Maritime Services
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
VDOP
VTG
WAAS
Inom
Imax
Vmax
Vnom
Vmin
VIHmax
Velocity
Wide Area Augmentation System Quectel
Minimum Voltage Value
Maximum Input High Level Voltage Value
VIHmin
VILmax
VILmin
VImax
VImin
VOHmax
Minimum Input High Level Voltage Value
Maximum Input Low Level Voltage Value Confidential
VOHmin
VOLmax
VOLmin
Minimum Output High Level Voltage Value
Maximum Output Low Level Voltage Value
Minimum Output Low Level Voltage Value
L70_HD_V1.0 - 8 -
L70 Hardware Design
2. Product concept
The L70 GPS module brings the high performance of the 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 storing user-specific configurations and allows for future updates.
The L70 module combines with many advanced features including AlwaysLocate
TM
, EASY
TM
, and
AIC. These features are beneficial to reduce consumption and accelerate TTFF for L70 module.
The module supports various location, navigation and industrial applications including autonomous
GPS, SBAS (including WAAS, EGNOS, MSAS, and GAGAN), QZSS, and AGPS.
The L70 is an SMD type module with the compact 10.1mm x 9.7mm x 2.5mm form factor, which can be embedded in customer applications through the 18-pin pads. It provides necessary hardware interfaces between the module and customer’s board.
The module is fully RoHS compliant to EU regulation. Quectel
Feature
Power supply
Implementation
Single supply voltage: 2.8V~4.3V typical : 3.3V
Acquisition 25mA@-130dBm
Tracking 22mA@-130dBm
Standby 0.5mA@VCC=3.3V
Power consumption (passive antenna)
Sensitivity
Confidential
Hot start -157 dBm
Tracking -160 dBm
Sensitivity
(with external LNA)
Time-To-First-Fix(EASY
Cold Start -148 dBm
Reacquisition -160 dBm
Hot Start -160 dBm
Tracking -163 dBm
Cold Start 15s average
@-130dBm
Warm Start
5s average @-130dBm
Hot Start 1s
@-130dBm enabled)
L70_HD_V1.0 - 9 -
RF_IN
L70 Hardware Design
Time-To-First-Fix(EASY disabled)
Cold Start (Autonomous) 35s average @-130dBm
Warm Start (Autonomous) 30s average @-130dBm
Hot Start (Autonomous) 1s@-130dBm
Horizontal Position <2.5 m CEP
Accuracy( @-130dBm )
Max Update Rate
Accuracy of 1PPS Signal
Velocity Accuracy
Acceleration Accuracy
Dynamic Performance
UART Port
Up to 10Hz,1Hz by default
Typical accuracy <15ns (Not support time service)
Time pulse width 100ms
Without Aid 0.1 m/s
Without Aid 0.1 m/s²
Maximum Altitude 18,000 m
Maximum Velocity 515 m/s Maximum
Acceleration 4 G
UART Port: TXD1 and RXD1
Supports baud rate from 4800bps to 115200bps，9600bps with default
UART Port is used for NMEA output, MTK proprietary messages input and firmware upgrade
Temperature range
Normal operation:
-40°C ~ +85°C
Physical Characteristics
2.2. Block diagram
Storage temperature: -45°C ~ +125°C
Size: 10.1±0.15 x 9.7±0.15 x 2.5±0.15mm
Weight: Approx.
0.6g
Quectel
The following figure shows a block diagram of L70 module. It consists of a single chip GPS IC which includes RF part and Baseband part, a SAW filter, a TCXO and a crystal oscillator.
Saw filter
TCXO
Fractional-N
Syntheszer
ROM
RAM
Serial
Flash
Active
Interference
Cancellation
Integrated
LDO
&PMU
GPS Engine
Peripheral controller
ARM7
Processor
RTC
VCC
VCC_RF
V_BCKP
UART
NRESET
EXTINT
1PPS
ANTON
32.768K XTAL
Figure 1: Module block diagram
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L70 Hardware Design
2.3. Evaluation board
In order to help customers on the application of L70 module, Quectel supplies an Evaluation Board
(EVB) with appropriate power supply, RS-232 serial cable, active antenna and other peripherals to test the module.
For more details, please refer to the document [1].
2.4. New technology
2.4.1. EASY technology
By Supplying aided information like ephemeris, almanac, rough last position and time, and satellite status，AGPS can help improve GPS receiver TTFF and the acquisition sensitivity. The L70 module supports EASY technology which is one kind of AGPS.
EASY works as an 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 these information for positioning if no
Quectel supplies power for the RTC circuit is necessary. If no backup power, L70 module cannot store the extended ephemeris information and predict orbit information, in other words, it will become the cold start. Although the EASY also can accelerate TTFF in cold start, the backup power is still strongly recommended.
EASY
TM
Confidential status of EASY. If EASY is enabled, the module returns “ $PMTK869,2,1*36”, else returns
“$PMTK869,2,0*37”.
2.4.2. AlwaysLocate
TM
mode
AlwaysLocate
TM
is an intelligent controller of L70 normal mode and sleep mode. It is one of the power saving modes. According to the environmental and motion conditions, L70 can adaptively adjust the on/off time to achieve the balance between positioning accuracy and power consumption.
L70_HD_V1.0 - 11 -
L70 Hardware Design
The following picture has shown the rough relationship between power consumption and the different scenarios in daily life when the AlwaysLocate
TM
mode is enabled.
Figure 2: AlwaysLocate
TM
mode
The position accuracy in AlwaysLocate
TM mode will be somewhat degraded, especially in high speed.
So this mode is not recommended in the applications of vehicle system.
AlwaysLocate
TM mode is disabled by default. Using the MTK proprietary commands can enable the
AlwaysLocate
TM mode. Please refer to the following commands to set the AlwaysLocate
TM
mode.
Enable AlwaysLocate
Quectel
2.4.3. Multi-tone AIC
mode: $PMTK225,8*23；Return: $PMTK001,225,3*33
Up to 12 multi-tone AIC (Active interference Cancellation) can provide effective narrow-band interference and jamming elimination. The GPS signal could be recovered from the jammed signal,
Confidential external RF interference which comes from other active components on the main board, to improve the capacity of GPS reception without any hardware change in the design.
AIC function is enabled by default. The following commands can be used to set AIC function.
Enable AIC function: $PMTK 286,1*23
Disable AIC function: $PMTK 286,0*22
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L70 Hardware Design
2.5. Protocol
The module supports standard NMEA-0813 protocol and MTK proprietary protocol (PMTK messages) that can be used to provide extended capabilities for many applications. The module is capable of supporting the following NMEA formats: GGA, GSA, GLL, GSV, RMC, VTG .
Table 4: The protocol supported by the module
Protocol
NMEA
PMTK
Type
Output, ASCII, 0183, 3.01
Input, MTK proprietary protocol
Note: Please refer to document [2] about NMEA standard protocol and MTK proprietary protocol.
Quectel
Confidential
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L70 Hardware Design
3. Application interface
The module is equipped with an 18-pin 1.1mm pitch SMT pad that connects to the user application platform. Sub-interfaces included in these pads are described in details in the following chapters.
3.1. Pin assignment of the module
10
11
9
8
GND
RF_IN
VRESET
VCC
12 NC 7
13
GND
ANTON
V_BCKP
6
L70
14
EXTINT0
5
15
VCC_RF
RESERVED
(Top View)
4 TIMEPULSE
16 3 NC RXD1
17 NC
TXD1
3.2. Pin description
Table 5: Pin description
Power Supply
18 RESERVED GND Quectel 1
2
PIN NAME PIN
VCC
V_BCKP
NO.
8
6
I/O DESCRIPTION
I
I
Supply voltage
Backup voltage
DC
CHARACTERISTICS
Vmax= 4.3V
Vmin=2.8V
Vnom=3.3V
Vmax=4.3V
COMMENT
Supply current of no less than 150mA.
Power supply for RTC supply Vmin=2.0V domain when VCC does not supply for the system. Vnom=2.8V
I
BCKP
=7uA@Backup mode
VCC_RF 14 O Output voltage RF section
Vmax=4.3V
Vmin=2.8V
Vnom=3.3V
Imax=50mA
Usually supply for external active antenna or LNA. If unused, keep this pin open.
V
VCC_RF
≈ V
VCC
Reset
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L70 Hardware Design
PIN NAME PIN
NO.
VRESET 9
I/O DESCRIPTION
I System reset, low level active.
DC
CHARACTERISTICS
VILmin=-0.3V
VILmax=0.8V
VIHmin=2.0V
VIHmax=3.6V
COMMENT
If unused, keep this pin open or connect it to the
VCC.
General purpose input/output
PIN NAME PIN I/O DESCRIPTION
NO.
EXTINT0 5 I External interrupt input
DC
CHARACTERISTICS
VILmin=-0.3V
VILmax=0.8V
VIHmin=2.0V
VIHmax= 3.6V
COMMENT
This pin can be used to enter or exit from the standby mode. If unused, keep this pin open.
Internally pulled up.
TIMEPULSE 4 O Time pulse
O Active antenna or external LNA control pin in power standby mode
VOLmin=-0.3V
VOLmax=0.4V
VOHmin=2.4V
VOHmax=3.1V
UART port
TXD1
PIN NAME PIN
RXD1
NO.
3
I/O DESCRIPTION
I Receive data
DC
CHARACTERISTICS
VILmin=-0.3V
Quectel COMMENT
2 O Transmit data VOLmin=-0.3V
VOLmax=0.4V
RF interface
PIN NAME PIN
NO.
I/O DESCRIPTION
VOHmin=2.4V
VOHmax=3.1V
DC
CHARACTERISTICS
RF_IN 11 I GPS signal input Characteristic impedance of 50Ω
COMMENT
Refer to chapter 4
ANTON 13 The typical value is
2.8V.
1 pulse per second (1PPS).
Synchronized at rising edge, the pulse width is100ms. If unused, keep this pin open.
This pin can be used to control the power supply of the Active antenna or the enable pin of the external
LNA in the standby mode.
If unused, keep this pin open.
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L70 Hardware Design
3.3. Operating modes
The table below briefly summarizes the various operating modes of L70 module.
Table 6: Overview of operating modes
Power saving mode
Mode
Acquisition
Tracking
mode mode
Standby mode
Function
The module starts to search satellite, determine visible satellites and coarse carrier frequency and code phase of satellite signals. When the acquisition is completed, it switches to tracking mode automatically.
The module refines acquisition’s message, as well as keeps tracking and demodulating the navigation data from the specific satellites.
Using EXTINT0 pin or PMTK command can make the module enter the standby mode. In this mode, the UART port is still accessible, but has no NEMA messages output, the current consumption of the module is also minimal.
When cutting off the main power supply, the module will enter the
Backup mode backup mode. In this mode, the RTC (Real Time Clock) power supply is needed. It can supply power for backed-up memory which contains all the necessary GPS information for quick start-up and a
Periodic standby mode small amount of user configuration variables.
Periodic standby mode is a periodic mode that can control the on/off supports the module to switch automatically between normal mode and standby mode.
AlwaysLocate
TM
is an intelligent controller of L70 periodic mode.
AlwaysLocate
TM
standby mode supports the module to switch
AlwaysLocate
TM automatically between normal mode and standby mode. According to standby mode
3.4. Power supply
the environmental and motion conditions, the module can adaptively adjust the on/off time to achieve the balance between positioning
Confidential
The main power supply is fed through the VCC pin. It is important that the system power supply circuitry is able to support the peak power. So the power supply must be able to provide sufficient current up to 150mA.
The power supply of RTC circuit is fed through the V_BCKP pin.
For more details, please refer to chapter 3.6.2.
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L70 Hardware Design
3.5. Turn on and Turn off
3.5.1. Turn on
The module will be turned on when VCC is supplied.
3.5.2. Turn off
Shutting down the module's main power supply is the only way to turn off the module. In this case, if the backup power is still present, the module will enter the backup mode.
3.5.3. Restart
L70 module can be restarted by driving the VRESET to a low level voltage for a certain time and then releasing it. An OC driver circuit as shown below is recommended to control the VRESET.
VRESET
Input pulse
Figure 3: Reference reset circuit using OC circuit
The other way to control the VRESET pin is using a button directly. A TVS component needs to be Confidential
VRESET
TVS1
Close to S1
Figure 4: Reference reset circuit using button
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L70 Hardware Design
The restart timing has been illustrated in Figure 5.
VCC
<170ms
Pulldown
> 10ms
V
IH
>2.0V
VRESET
(INPUT)
V
IL
<0.8V
3.6. Power saving modes
Figure 5: Timing of restarting system
3.6.1. Standby mode
Standby mode is one of the power saving modes, in this mode, the UART serial port is still accessible, but has no NEMA messages output, the current consumption of the module is also minimal. The following table has shown the ways how to enter and exit from the standby mode.
Mode
Quectel
Enter the
Changing the level of EXTINT0 pin from high to low. standby mode
Exit from standby mode
Sending the MTK proprietary command“$PMTK l61,0*28 ”.
Changing the level of EXTINT0 pin from low to high.
Note: Recommended to pull EXTINT0 pin high before turning on the module.
3.6.2. Back up mode
When cutting off the main power supply, the module will enter the backup mode. In this mode, the
RTC (Real Time Clock) power supply is needed. It can supply power for backed-up memory which contains all the necessary GPS information for quick start-up and a small amount of user configuration variables. The RTC power supply of module can be directly provided by an external capacitor or battery (rechargeable or non-chargeable) through the V_BCKP pin.
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L70 Hardware Design
Table 8: Pin definition of the V_BCKP pin
Name
V_BCKP
Pin No. Function
6 Backup voltage supply
Note: The V_BCKP could not keep open. The V_BCKP pin should be connected to a battery or a capacitor for GPS module warm/hot start and AGPS.
Please refer to the following figure for RTC backup:
V_BCKP
MODULE
RTC
LDO
Non-chargeable battery or capacitor
Figure 6: RTC supply from non-chargeable battery or capacitor Quectel
1K
Charge Circuit
VCC
Chargeable
Backup Battery
V_BCKP
MODULE
RTC
LDO
Confidential
Figure 7: Reference charging circuit for chargeable battery
Coin-type Capacitor backup
Coin-type Rechargeable Capacitor such as XH414H-IV01E from Seiko can be used.
L70_HD_V1.0 - 19 -
L70 Hardware Design
Figure 8: Seiko XH414H-IV01E charge characteristic
3.6.3. Periodic standby mode
Periodic standby mode is a periodic mode that can control the on/off time of L70 module periodically to reduce power consumption. It supports the module switches automatically between normal mode
Quectel
Confidential
Figure 9: Periodic mode
Sending PMTK command can enter periodic standby mode. The ratio of run time and sleep time can be set by the command. For more details, please refer to document [2] about the MTK proprietary protocol.
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L70 Hardware Design
3.6.4. AlwaysLocate
TM
standby mode
AlwaysLocate
TM
is an intelligent controller of L70 normal mode and standby mode. AlwaysLocate
TM standby
mode supports the module to switch automatically between normal mode and standby mode.
According to the environmental and motion conditions, the module can adaptively adjust the on/off time to achieve the balance between positioning accuracy and power consumption.
For more details, please refer to chapter 2.4.2.
3.7. 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 signal shown as Figure 10. 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
Interface
Quectel
UART Port
TXD1
RXD1
2
3
Transmit data
Receive data
MODULE (DCE)
Serial port
TXD1
RXD1
RXD
GND
GND
Figure 10: Connection of serial interfaces
This UART port has the following features:
UART port can be used for firmware upgrade, NMEA output and PMTK proprietary messages
L70_HD_V1.0 - 21 -
L70 Hardware Design input.
The default output NMEA type setting is RMC, VTG, GGA, GSA, GSV, GLL.
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 supports the 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.
28 27
C1+ V+
25 2
C1GND
1 26
C2+ VCC 3.3V
3 4
C2V-
TXD1
24
23
T1IN
T2IN
T4OUT
T2OUT
22
19
T3IN
T4IN
10
6
7
17
T5IN
T3OUT
T1OUT
T5OUT
5
12
Module
16
21
20
/R1OUT
R2OUT
R3OUT
8
9
11
RXD1
3.3V
18
13
R1OUT
ONLINE
R1IN
R2IN
R3IN Quectel
6
7
8
9
1
2
3
4
5
To PC serial port
GND
3.8.
ANTON
Figure 11: RS-232 level shift circuit
Confidential enable pin of the external LNA. The recommended circuit diagram is shown in Figure 12. When L70 module enters the standby mode, the ANTON pin will be pulled down, the Q1 and Q2 are in high impedance state and the power supply for antenna is cut off. In normal mode, the voltage value of
ANTON is about 2.8V, it will make Q1 and Q2 in the on-state, then VCC_RF will provide power supply for the active antenna. Figure 13 has shown the timing between the ANTON pin and the
EXTINT0 pin.
L70_HD_V1.0 - 22 -
L70 Hardware Design
Table 10: Pin definition of the ANTON
Name Pin No. Function
ANTON 13 Control the power supply of the active GPS antenna or the enable pin of the external LNA.
Active Antenna
LNA
L70_Module
RF_IN
R3 100R
L1 47nH
R1 10R
Q2
Q1
R2 10K
ANTON
VCC_RF
Confidential
Figure 13: Timing of EXTINT0 and ANTON
L70_HD_V1.0 - 23 -
L70 Hardware Design
4. Antenna interface
The L70 module receives L1 band signal from GPS satellites at a nominal frequency of 1575.42MHz.
The RF signal is connected to the RF_IN pin. Customer should use a controlled impedance transmission line of 50 Ohm to connect to RF_IN.
4.1. Antenna
L70 module can be connected to passive or active antenna.
Table 11: Antenna specification for L70 module
Antenna type
Passive antenna
Specification
Center frequency: 1575.42 MHz
Band Width: >20 MHz
Gain: >0 dBi
Polarization: RHCP or Linear
Active antenna Quectel
4.2. Antenna supply
Center frequency: 1575.42 MHz
Band Width: >5 MHz
Minimum gain: 15-20dB(compensate signal loss in RF cable)
Maximum noise figure: 1.5dB
Maximum gain: 50dB
Polarization: RHCP or Linear
Confidential to add for improving receiver sensitivity. It is always beneficial to reserve a П or L passive matching network between the passive antenna and the LNA. Figure14 is the rough reference design. For more details, please refer to document [3].
L70_HD_V1.0 - 24 -
L70 Hardware Design
Passive Antenna
R1 0R
BGA715L7
LNA
L70_Module
RF_IN
C1 NM C2 NM
R2
150R
П matching circuit
R3
100R
ANTON
VCC_RF
Figure 14: Reference design for passive antenna with LNA
Note: VCC_RF is directly connected to the power supply of L70 module internally. If VCC_RF is not suitable to the external LNA, using R2 as a divider or adding an external LDO circuit to get the required voltage. R3 is used as a current limiting resistor. Quectel to RF_IN, the integrated low-noise amplifier of the antenna must be powered by an external correct supply voltage. Generally, the supply voltage is fed to the antenna through the coaxial RF cable. An active antenna’s loading current is between 5mA to 20mA. The inductor L1 outside of the module prevents the RF signal from leaking into the VCC_RF pin and routes the bias supply to the active
Confidential
L70_HD_V1.0 - 25 -
L70 Hardware Design
Active Antenna
П matching circuit
C1 NM
R3 0R
10R
L1 47nH R1
Q1
Q2
C2 NM
L70_Module
RF_IN
R2
10K
ANTON
VCC_RF
Figure 15: Reference design for active antenna without LNA
Note: The rated power of resistor R1 should be chosen no less than 1 watt in case active antenna is shorted unexpectedly. In order to reduce consumption, the value of resistor R2 is not recommended to choose too small.
In order to obtain better receiver sensitivity, an active antenna and an external LNA are recommended.
You also can reserve a П or L passive matching network between the active antenna and the LNA. The rough reference circuit is shown in Figure16. For more details, please refer to document [3].
Active Antenna П matching circuit
C1 NM C2 NM
R3 0R
LNA
RF_IN
L1
R1
Q2
Q1
R4
R5
R2 ANTON
VCC_RF
Figure 16: Reference design for active antenna with LNA
L70_HD_V1.0 - 26 -
L70 Hardware Design
5. Electrical, reliability and radio characteristics
5.1. Absolute maximum ratings
Absolute maximum rating for power supply and voltage on digital pins of the module are listed in
Table 12.
Table 12: Absolute maximum ratings
Parameter
Power supply voltage （VCC）
Backup battery voltage (V_BCKP)
Input voltage at digital pins
VCC_RF output current (Ivccrf)
Input power at RF_IN (Prfin)
Storage temperature
Min
-0.3
-0.3
-0.3
-45
Max
4.3
4.3
3.6
50
0
125
Unit
V
V
V mA dBm
°C
Note: 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,
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Table 13: The module power supply ratings
I
VCCP
*
Parameter Description
VCC Supply voltage
V_BCKP Backup voltage supply
Conditions
Voltage must stay within the min/max values, including voltage drop, ripple, and spikes.
Min
2.8
2.0
Typ
3.3
3.3
Max Unit
4.3 V
Confidential
Peak supply current VCC=3.3V 150 mA
4.3 V
VCC V VCC_RF Output voltage RF section
I
VCC_RF
T
OPR
VCC_RF output current
Normal Operating temperature
50 mA
-40 25 85 ℃
L70_HD_V1.0 - 27 -
L70 Hardware Design
* This figure can be used to determine the maximum current capability of power supply.
Note: Operation beyond the "Operating Conditions" is not recommended and extended exposure beyond the "Operating Conditions" may affect device reliability.
5.3. Current consumption
The values for current consumption are shown in Table 14.
Table 14: The module current consumption (passive antenna)
Parameter Condition
Icc @Acquisition @-130dBm
Icc @Tracking
Icc @Standby
@-130dBm（For Cold Start, 10 minutes after First Fix. For Hot
Start, 15 seconds after First
Fix.）
@VCC=3.3V
Min Typ
25
22
0.5
I
BCKP
@backup @ V_BCKP=3.3V
be re-activated when the module exits from the standby mode.
7
Max Unit mA mA mA uA
5.4. Electro-static discharge
L70 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
Confidential
Table 15: The ESD endurance table (Temperature: 25℃, Humidity: 45 %)
Pin
RF_IN
VCC,GND
UART
Others
Contact discharge
±5KV
±5KV
±3KV
±2KV
Air discharge
±10KV
±10KV
±6KV
±4KV
L70_HD_V1.0 - 28 -
L70 Hardware Design
5.5. Reliability test
Table 16: Reliability test
Test term
Thermal shock
Condition
-30°C...+80°C, 144 cycles
Damp heat, cyclic +55°C; >90% Rh 6 cycles for 144 hours
Vibration shock 5~20Hz,0.96m
2
/s
3
;20~500Hz,0.96m
2
/s
3
-3dB/oct,
1hour/axis; no function
Heat test 85° C, 2 hours, Operational
Cold test
Heat soak
Cold soak
-40° C, 2 hours, Operational
90° C, 72 hours, Non-Operational
-45° C, 72 hours, Non-Operational
Standard
GB/T 2423.22-2002 Test
Na
IEC 68-2-14 Na
IEC 68-2-30 Db Test
2423.13-1997 Test Fdb
IEC 68-2-36 Fdb Test
GB/T 2423.1-2001 Ab
IEC 68-2-1 Test
GB/T 2423.1-2001 Ab
IEC 68-2-1 Test
GB/T 2423.2-2001 Bb
IEC 68-2-2 Test B
GB/T 2423.1-2001 A
IEC 68-2-1 Test
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Confidential
L70_HD_V1.0 - 29 -
L70 Hardware Design
6. Mechanics
This chapter describes the mechanical dimensions of the module.
6.1. Mechanical view of the module
Figure 17: L70 Top view and Side view（Unit:mm）
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Confidential
Figure 18: L70 Bottom dimension（Unit:mm）
L70_HD_V1.0 - 30 -
L70 Hardware Design
Keep Out
Figure 19: Footprint of recommendation（Unit:mm）
Notes
：
1. The keep-out area should be covered by solder mask and top silk layer for isolation between the top layer of host board and the bottom layer of the module.
2. For easy maintenance of this module and accessing to these pads, please keep a distance of no
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1 18
Confidential
9 10
Figure 20: Top view of the module
L70_HD_V1.0 - 31 -
L70 Hardware Design
6.4. Bottom view of the module
18 1
10 9
Figure 21: Bottom view of the module
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Confidential
L70_HD_V1.0 - 32 -
L70 Hardware Design
7. Manufacturing
7.1. Assembly and soldering
L70 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 130um to ensure sufficient solder volume. Pad openings of paste mask can be increased to ensure proper soldering and solder 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.
Preheat Heating
℃
250
217
200
50
150
100
Liquids Temperature
200℃
40s~60s
160℃
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Between 1~3℃/S
Cooling
0 50 100 150 200 250 300 s
Figure 22: Ramp-soak-spike-reflow of furnace temperature
7.2. Moisture sensitivity
L70 is sensitivity to moisture absorption. To prevent L70 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.
L70_HD_V1.0 - 33 -
L70 Hardware Design
L70 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. L70 should be taken out before preheating, otherwise, the tray maybe damaged by high-temperature heating.
7.3. ESD safe
L70 module is an ESD sensitive device and should be careful to handle.
7.4. Tape and reel
Out direction
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Unit: mm
Confidential
Figure 23: Tape and reel specification
L70_HD_V1.0 - 34 -
Shanghai Quectel Wireless Solutions Co., Ltd.
Room 501, Building 13, No.99, TianZhou Road, Shanghai, China 200233
Tel: +86 21 5108 6236
Mail: [email protected]
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Key Features
- High sensitivity, accuracy and TTFF
- Low power consumption
- Small-footprint lead-free package
- 66 search channels and 22 simultaneous tracking channels
- Embedded flash memory
- Support for various location, navigation and industrial applications
- RoHS compliant
- Support for EASY technology
- Support for AlwaysLocateTM mode
- Support for multi-tone AIC
