EVA-M8E - Hardware Integration Manual
UBX-15028542 - R05
Contents
Page 18 of 44
Production Information
2.8
Design-in checklist
2.8.1
General considerations
Check power supply requirements and schematic:
Is the power supply voltage within the specified range? See how to connect power in Section 2.1.
For USB devices: Is the voltage
VDD_USB
voltage within the specified range? Do you have a Bus
or Self powered setup?
Compare the peak current consumption of EVA-M8E with the specification of your power
supply.
GNSS receivers require a stable power supply. Avoid series resistance in your power supply line
(the line to
VCC
) to minimize the voltage ripple on
VCC
.
Backup battery
For achieving a minimal Time To First Fix (TTFF) after a power down (warm starts, hot starts),
make sure to connect a backup battery to
V_BCKP
, and use an RTC. If not used, make sure
V_BCKP
is connected to
VCC_IO
.
Antenna/ RF input
The total noise figure including external LNA (or the LNA in the active antenna) should be around
1 dB.
With the EVA-M8E module, an external LNA is mandatory if no active antenna is used to achieve
the performance values as written in the EVA-M8E Data Sheet [1].
Make sure the antenna is not placed close to noisy parts of the circuitry and not facing noisy
parts. (e.g. micro-controller, display, etc.)
To optimize performance in environments with out-band jamming/interference sources, use an
additional SAW filter.
☞
For more information dealing with interference issues see the GPS Antenna Application Note [3].
Schematic
Inner pins of the package must all be connected to GND.
2.8.2
Schematic design-in for EVA-M8E
For a minimal design with the EVA-M8E the following functions and pins need to be considered:
•
Connect the power supply to VCC, VCC_IO and V_BCKP.
•
VDD_USB: Connect the USB power supply to a LDO before feeding it to VDD_USB and VCC or
connect it to GND if USB is not used.
•
Ensure an optimal ground connection to all ground pins of the EVA-M8E module.
•
Choose the required serial communication interfaces (UART, USB, DDC) and connect the
appropriate pins to your application
•
If you need hot or warm start in your application, connect a Backup Battery to V_BCKP and add
RTC circuit.
•
If antenna bias is required, see Appendix A.4.
