u-blox LEA-M8S Hardware Integration Manual
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u-blox LEA-M8S Hardware Integration Manual

u-blox LEA-M8S Hardware Integration Manual

M8 concurrent gnss modules
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LEA-M8S / LEA-M8T
u-blox M8 concurrent GNSS modules
Hardware Integration Manual
Abstract
This document describes the features and specifications of the cost
effective and high-performance LEA-M8S and LEA-M8T modules,
which feature the u-blox M8 concurrent GNSS engine with
reception of GPS, GLONASS, BeiDou and QZSS signals.
www.u-blox.com
UBX-13003140 - R07

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  • Page 1 Hardware Integration Manual Abstract This document describes the features and specifications of the cost effective and high-performance LEA-M8S and LEA-M8T modules, which feature the u-blox M8 concurrent GNSS engine with reception of GPS, GLONASS, BeiDou and QZSS signals. www.u-blox.com UBX-13003140 - R07...
  • Page 2 The information contained herein is provided “as is” and u-blox assumes no liability for the use of the information. No warranty, either express or implied, is given, including but not limited, with respect to the accuracy, correctness, reliability and fitness for a particular purpose of the information.

  • Page 3: Table Of Contents

    2.4.2 Active antenna design ................................ 12 Migration to u-blox M8 modules ................18 Migrating u-blox 6 designs to a u-blox M8 module ........................18 Hardware migration LEA-6N -> LEA-M8S ..........................18 Hardware migration LEA-6T -> LEA-M8T ..........................19 Software migration ................................19 Product handling ......................

  • Page 4: Hardware Description

    For this reason, it is important that the supply circuitry is able to support the peak power for a short time (see the LEA-M8S Data Sheet [1] and the NEO/LEA-M8T Data Sheet [2] for detail specification).

  • Page 5: Vdd_Usb: Usb Interface Power Supply

    LEA-M8S / LEA-M8T - Hardware Integration Manual Figure 1: Backup battery and voltage (for exact pin orientation, see the LEA-M8S Data Sheet [1] and the NEO/LEA-M8T Data Sheet [2]) 1.3.3 VDD_USB: USB interface power supply VDD_USB supplies the USB interface. If the USB interface is not used, the VDD_USB pin must be connected to GND.

  • Page 6: Display Data Channel (Ddc)

    UART TXD (PIO 06). The TX Ready function is disabled by default. The TX-ready functionality can be enabled and configured by AT commands sent to the involved u-blox cellular module supporting the feature. For more information, see the GPS Implementation and Aiding Features in u-blox wireless modules [9].

  • Page 7: I/O Pins

    SAFEBOOT_N If the SAFEBOOT_N pin is “low” at start up, the u-blox M8 module starts in Safe Boot Mode and doesn’t begin GNSS operation. The Safe Boot Mode can be used to recover from situations where the Flash has become corrupted.

  • Page 8: Electromagnetic Interference On I/O Lines

    LEA-M8S / LEA-M8T - Hardware Integration Manual Electromagnetic interference on I/O lines Any I/O signal line with a length greater than approximately 3 mm can act as an antenna and may pick up arbitrary RF signals transferring them as noise into the GNSS receiver. This specifically applies to unshielded lines, in which the corresponding GND layer is remote or missing entirely, and lines close to the edges of the printed circuit board.

  • Page 9: Design

    LEA-M8S / LEA-M8T - Hardware Integration Manual 2 Design 2.1 Pin description Function Description Remarks Power Supply Voltage Provide clean and stable supply. Assure a good GND connection to all GND pins of the module 7, 13, 14, Ground 15, 17...

  • Page 10: Minimal Design

    For active antenna design, see section 2.4 2.3 Footprint and paste mask Figure 5 describes the footprint and provides recommendations for the paste mask for the LEA-M8S and LEA-M8T modules. These are recommendations only and not specifications. Note that the copper and solder masks have the same size and position.

  • Page 11: Antenna And Antenna Supervision

    Minimal setup with a good patch antenna Figure 7 shows a minimal setup for a design with a good GNSS patch antenna. Figure 7: Module design with passive antenna (for exact pin orientation see the LEA-M8S Data Sheet [1] and the NEO/LEA-M8T Data Sheet [2])

  • Page 12: Active Antenna Design

    Figure 8 shows a design using an external LNA to increase the sensitivity for best performance with passive antenna. Figure 8: Module design with passive antenna and an external LNA (for exact pin orientation see the LEA-M8S Data Sheet [1] and the NEO/LEA-M8T Data Sheet [2].) The VCC_RF output can be used to supply the LNA with a filtered supply voltage.
  • Page 13 This circuit has to be used if the active antenna has a different supply voltage than the VCC_RF (for example if a 5 V active antenna is used). Figure 10: Active antenna design, direct external supply (for exact pin orientation see the LEA-M8S Data Sheet [1] and the NEO/LEA-M8T Data Sheet [2]) For recommended parts, see Appendix.
  • Page 14 Status reporting At startup, and on every change of the antenna supervisor configuration, the LEA-M8S and LEA-M8T modules will output an NMEA ($GPTXT) or UBX (INF-NOTICE) message with the internal status of the antenna supervisor (disabled, short detection only, enabled).
  • Page 15 MON- Figure 12: Module design with active antenna, internal supply from VCC_RF (for exact pin orientation see the LEA-M8S Data Sheet [1] and the NEO/LEA-M8T Data Sheet [2].)
  • Page 16 1.561 GHz. Therefore, it is not recommended to use digital supply nets to feed the V_ANT pin. Figure 13: Module design with active antenna, external supply (for exact pin orientation see the LEA-M8S Data Sheet [1] and the NEO/LEA-M8T Data Sheet [2])
  • Page 17 LEA-M8S / LEA-M8T - Hardware Integration Manual       • Rbias Equation 1: Calculation of threshold current for open circuit detection If the antenna supply voltage is not derived from VCC_RF, do not exceed the maximum voltage rating of AADET_N.

  • Page 18: Migration To U-Blox M8 Modules

    If using BeiDou, check the bandwidth of the external RF components and the antenna. For information about power consumption, see the LEA-M8S Data Sheet [1] and the NEO/LEA-M8T Data Sheet [2]. It is highly advisable that customers consider a design review with the u-blox support team to ensure the compatibility of key functionalities.

  • Page 19: Hardware Migration Lea-6T -> Lea-M8T

    For overall description of the module software operation, see the u-blox M8 Receiver Description Including Protocol Specification [3]. All features requiring a flash on LEA-6N are not supported on LEA-M8S. (AssistNow offline / save config) UBX-13003140 - R07 Production Information...

  • Page 20: Product Handling

    4.1 Packaging, shipping, storage and moisture preconditioning For information pertaining to reels and tapes, Moisture Sensitivity levels (MSL), shipment and storage information, as well as drying for preconditioning see the LEA-M8S Data Sheet [1] and the NEO/LEA-M8T Data Sheet [2].
  • Page 21 • Temperature fall rate: max 4 °C/s To avoid falling off, the u-blox M8 GNSS module should be placed on the topside of the motherboard during soldering. The final soldering temperature chosen at the factory depends on additional external factors like choice of soldering paste, size, thickness and properties of the baseboard, etc.
  • Page 22 Rework The u-blox M8 module can be unsoldered from the baseboard using a hot air gun. When using a hot air gun for unsoldering the module, a maximum of one reflow cycle is allowed. In general, we do not recommend using a hot air gun because this is an uncontrolled process and might damage the module.

  • Page 23: Eos/Esd/Emi Precautions

    EMI covers is done at the customer’s own risk. The numerous ground pins should be sufficient to provide optimum immunity to interferences and noise. u-blox makes no warranty for damages to the u-blox M8 module caused by soldering metal cables or any other forms of metal strips directly onto the EMI covers.
  • Page 24 LEA-M8S / LEA-M8T - Hardware Integration Manual • When handling the RF pin, do not come into contact with any charged capacitors and be careful when contacting materials that can develop charges (e.g. patch antenna ~10 pF, coax cable ~50 –...
  • Page 25 LEA-M8S / LEA-M8T - Hardware Integration Manual EOS protection measures For designs with GNSS positioning modules and wireless (e.g. GSM/GPRS) transceivers in close proximity, ensure sufficient isolation between the wireless and GNSS antennas. If wireless power output causes the specified maximum power input at the GNSS RF_IN to be exceeded, employ EOS protection measures to prevent overstress damage.

  • Page 26: Applications With Cellular Modules

    LEA-M8S / LEA-M8T - Hardware Integration Manual 4.4 Applications with cellular modules GSM uses power levels up to 2 W (+33 dBm). Consult the LEA-M8S Data Sheet [1] and the NEO/LEA-M8T Data Sheet [2] for the absolute maximum power input at the GNSS receiver.
  • Page 27 LEA-M8S / LEA-M8T - Hardware Integration Manual Measures against in-band interference include: • Maintaining a good grounding concept in the design • Shielding • Layout optimization • Filtering • Placement of the GNSS antenna • Adding a CDMA, GSM, WCDMA band pass filter before handset antenna Out-band interference Out-band interference is caused by signal frequencies that are different from the GNSS carrier (see Figure 20).

  • Page 28: Appendix

    LEA-M8S / LEA-M8T - Hardware Integration Manual Appendix Recommended parts Recommended parts are selected on data sheet basis only. Other components may also be used. Manufacturer Part ID Remarks Parameters to consider Diode ESD9R3.3ST5G Standoff Voltage>3.3 V Low Capacitance < 0.5 pF Semiconductor ESD9L3.3ST5G...

  • Page 29: Design-In Recommendations In Combination With Cellular Operation

      • = integrated  = optimal performance Table 9: Combinations of u-blox GNSS modules with different cellular technologies (2G/3G/4G). See the GPS Implementation and Aiding Features in u-blox wireless modules [9]. UBX-13003140 - R07 Production Information Appendix Page 29 of 31...

  • Page 30: Related Documents

    I2C-bus specification, Version 2.1, Jan 2000, http://www.nxp.com/acrobat_download/literature/9398/39340011_21.pdf GPS Implementation and Aiding Features in u-blox wireless modules, Docu. No. GSM.G1-CS-09007 For regular updates to u-blox documentation and to receive product change notifications please register on our homepage (http://www.u-blox.com) Revision history Revision...

  • Page 31: Contact

    LEA-M8S / LEA-M8T - Hardware Integration Manual Contact For complete contact information, visit us at www.u-blox.com u-blox Offices North, Central and South America Headquarters Asia, Australia, Pacific Europe, Middle East, Africa u-blox America, Inc. u-blox Singapore Pte. Ltd. u-blox AG...

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