Hardware Description; Overview; Configuration; Connecting Power - u-blox M8 Series Hardware Integration Manual

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Hardware description

1.1 Overview

The NEO-M8L modules are 3D dead reckoning GNSS receivers for automotive applications using a
built-in 6-axis sensor (3-axis gyroscope and 3-axis accelerometer) and featuring the high performance
u-blox M8 concurrent positioning engine. Available in the NEO industry standard leadless chip carrier
(LCC) package, 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 & place and reflow-soldering equipment for cost-efficient, high-volume production
enabling short time-to-market.
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For more information about the product features, see the corresponding product data sheet [1],
[2], or [3] in the Related documents section.
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To determine which u-blox product best meets your needs, see the product selector tables on the
u-blox website www.u-blox.com.

1.2 Configuration

The configuration settings can be modified using UBX protocol configuration messages (see the u-
blox 8 / u-blox M8 Receiver Description Including Protocol Specification [4]). The modified settings
remain effective until power-down or reset. If these settings have been stored in battery-backed RAM
(BBR), then the modified configuration will be retained, as long as the backup battery supply is not
interrupted.
For NEO-M8L modules, the configuration can be saved permanently in SQI flash.

1.3 Connecting power

The NEO-M8L 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 be able to support the peak power for a short time (see the
corresponding product data sheet in the Related documents section for the specifications).
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When switching from backup mode to normal operation or at start-up, the NEO-M8L 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 startup will improve the
GNSS performance, as with hot starts, warm starts, AssistNow Autonomous and AssistNow Offline.
If no backup battery is connected, the module performs a cold start at power up.
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A backup supply voltage should be provided to the NEO-M8L to enable navigation by dead
reckoning before the first GNSS fix.
UBX-16010549 - R08
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NEO-M8L - Hardware integration manual
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