MAX-M5Q - Hardware Integration Manual
FTX-HW-13008
Objective Specification
Design
Page 13 of 40
3
Design
3.1
Design checklist
Designing-in a MAX-M5Q module is easy, especially when based on a u-blox reference design. Nonetheless, it
pays to do a quick sanity check of the design. This section lists the most important items for a simple design
check. The design checklist can also help to avoid an unnecessary PCB respin and achieve the best possible
performance. Follow the design checklists when developing any MAX-M5Q GPS/GNSS applications. This can
significantly reduce development time and costs.
3.1.1
Schematic checklist
Power supply requirements
GPS/GNSS positioning modules require a stable power supply. In selecting a strategy to achieve a clean
and stable power supply, any resistance in the
VCC
supply line can negatively influence performance.
Consider the following points:
o
Wide power lines or even power planes are preferred.
o
Avoid resistive components in the power line (e.g. narrow power lines, coils, resistors, etc.).
o
Placing a filter or other source of resistance at
VCC
can create significantly longer acquisition
times.
o
For ground plane design, see section 3.4.3.
Ensure that all power supplies are within the specified range. (See MAX-M5Q Data Sheet, Docu. No FTX-
HW-13003 [1])
Compare the peak supply current consumption of your MAX-M5Q module
with the specification of the
power supply. (See MAX-M5Q Data Sheet, Docu. No FTX-HW-13003 [1])
At the module input, use low ESR capacitors that can deliver the required current/charge for switching
from backup mode to normal operation.
For compatibility (migration path for MAX-7 and MAX-8), Pin 7 (Reserved) must be connected to
VDD
.
Backup battery
Use of valid time and the GPS/GNSS orbit data at startup will improve the GPS/GNSS performance, i.e.
enables hot and warm starts. To make use of these features connect a battery to
V_BCKP
to continue
supplying the backup domain in case of power failure at
VCC
.
If no backup supply voltage is available, connect the
V_BCKP
pin to
VCC
).