NEO-8Q / NEO-M8 - Hardware Integration Manual
UBX-15029985 - R04 Production Information Hardware description
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1 Hardware description
1.1 Overview
u-blox NEO-8Q, NEO-M8N, NEO-M8Q, and NEO-M8M standard precision GNSS modules, and the NEO-M8T
timing GNSS module, all feature the high performance u-blox M8 GNSS engine. Available in the industry
standard NEO form factor in a 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.
For product features, see the corresponding product data sheet in the Related documents.
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 BBR (Battery Backed RAM), then the modified configuration
will be retained, as long as the backup battery supply is not interrupted.
For the NEO-M8N module, configuration can be saved permanently in SQI flash.
1.3 Connecting power
The u-blox NEO-8Q and NEO-M8 series modules have 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 Related documents for the specifications).
When switching from backup mode to normal operation or at start-up, u-blox NEO-8Q and NEO-M8 series
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.
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, 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.
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.
If no backup supply voltage is available, connect the V_BCKP pin to VCC.
As long as power is supplied to the NEO-8Q and NEO-M8 series modules through the VCC pin, the backup
battery is disconnected from the RTC and the BBR to avoid unnecessary battery drain (see Figure 1). In this
case, VCC supplies power to the RTC and BBR.