LEA-M8S / LEA-M8T - Hardware integration manual
UBX-15030060 - R06
Hardware description
Page 5 of 33
Production information
1
Hardware description
1.1
Overview
LEA-M8S and LEA-M8T are concurrent GNSS positioning modules featuring the high performance
u-blox M8 positioning engine. They are easy to integrate and combine exceptional positioning
performance with highly flexible power, design, and connectivity options. SMT pads allow fully
automated assembly with standard pick-and-place and reflow-soldering equipment for cost-efficient,
high-volume production enabling short time-to-market.
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For specific product features, see LEA-M8S Data sheet [1] and NEO / LEA-M8T Data sheet [2].
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To determine which u-blox product best meets your needs, see the product selector tables on the
u-blox website.
1.2
Configuration
The configuration settings can be modified using UBX protocol configuration messages, for more
information see the u-blox 8 / u-blox M8 Receiver Description Including Protocol Specification [3]. The
modified settings remain effective until power-down or reset. If these settings have been stored in
Battery Backed RAM (BBR), the modified configuration will be retained, as long as the backup battery
supply is not interrupted.
1.3
Connecting power
The LEA-M8S and LEA-M8T positioning modules have up to three power supply pins: VCC, V_BCKP
and VDD_USB.
1.3.1
VCC: Main supply voltage
The VCC pin provides the main supply voltage. During operation, the current drawn by the module can
vary by some orders of magnitude, especially if enabling low-power operation modes. 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
Error! Reference source not found. for
etailed specifications).
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When switching from backup mode to normal operation or at start-up, the LEA-M8S and LEA-
M8T modules must charge the internal capacitors in the core domain. In certain situations, this
can result in a significant current draw. For low-power applications using power save and backup
modes, it is important that the power supply or low ESR capacitors at the module input can deliver
this current/charge.
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Use a proper GND concept. Do not use any resistors or coils in the power line.
1.3.2
V_BCKP: Backup supply voltage
If the module supply has a power failure, the V_BCKP pin supplies the real-time clock (RTC) and
battery-backed RAM (BBR). Use of valid time and the GNSS orbit data at start-up will improve the
GNSS performance, that is, it enables hot and warm starts. If no backup battery is connected, the
module performs a cold start at power-up.
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Avoid high resistance on the V_BCKP line: During the switch from main supply to backup supply,
a short current adjustment peak can cause high voltage drop on the pin with possible
malfunctions.
