EVK-M8U - User Guide

UBX-15023994 - R05

Device description

Page 7 of 27

3 Device description

3.1 Interface connection and measurement

For connecting the EVK to a PC, use a standard SUBD-9 cable and the included USB cable. The use of

RS232 and external power supply is optional. USB provides both power and a communications

channel.

Figure 1: Connecting the unit for power supply and communication

3.2 Active antenna

The EVK-M8U evaluation kit includes a GPS / GLONASS / BeiDou antenna with a 3 m cable. It is

possible to connect various active and passive GNSS antennas to the evaluation unit with SMA

connectors.

The recommended maximum antenna supply current for active antennas is 30 mA.

3.3 Evaluation unit

Figure 2 shows the front and the rear panel of the EVK-M8U evaluation unit.

Front panel

Rear panel

Figure 2: EVK-M8U evaluation unit – front and rear panels

3.3.1 Antenna connector

An SMA female jack is available on the front side (see Figure 2) of the evaluation unit for connecting

an active or passive antenna. The EVK provides a DC supply at the RF input of 3.3 V for active

antennas. The maximum supported antenna current is 30 mA; internal protection limits the

maximum short circuit current to 60 mA.

To avoid the damage of RF input caused by ESD or electrical overstress, and to seek maximum

consistency and repeatability of performance independently of the RF component used, the EVK-

M8U has an onboard LNA.

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The connector is only to be used with a GNSS antenna or simulator. Do not connect this equipment

to cable distribution systems.