EVA-8M and EVA-M8 series - Hardware Integration Manual
UBX-16010593 - R06
Design-in
Page 7 of 47
Early Production Information
2
Design-in
In order to obtain good performance with EVA-8M / EVA-M8 series GNSS receiver modules, there are
a number of issues requiring careful attention during the design-in. These include:
•
Power Supply:
Good performance requires a clean and stable power supply.
•
Interfaces:
Ensure correct wiring, rate and message setup on the module and your host system.
•
Antenna interface:
For optimal performance, seek short routing, matched impedance and no stubs.
•
External LNA
:
With EVA-M8 and EVA-M8M modules, an additional external LNA is
mandatory
if a
passive antenna is used. With EVA-M8Q module, an additional external LNA is
recommended
with passive antenna
.
2.1
Power management
2.1.1
Overview
The EVA-8M / EVA-M8 series GNSS modules provide four supply pins:
VCC
,
VCC_IO
,
V_BCKP
and
VDD_USB
. They can be supplied independently or tied together to adapt various concepts, depending
on the intended application. The different supply voltages are explained in the following subsections.
Figure 1 shows an example to supply the EVA-8M / EVA-M8 series modules when not using the USB
interface. In this case, the
VDD_USB
pin is connected to ground.
Figure 1: EVA-8M / EVA-M8 series power supply example
2.1.1.1
Main supply voltage (VCC)
During operation, the EVA-8M / EVA-M8 series GNSS modules are supplied through the
VCC
pin. It
makes use of an internal DC/DC converter for improved power efficiency. In a following step, built-in
