User's Manual

MeiG hardware design guide
33
The LTE antenna is the main source of coupling interference for FDD, so users should pay attention
to keeping the audio trace away from the LTE antenna and VBAT during PCB layout and routing. The
filter capacitor of the audio is preferably placed close to the module end and placed next to the
interface end. The audio output should be routed according to the differential signal rules.
The conducted interference is mainly caused by the voltage drop of VBAT. If the Audio PA is directly
powered by VBAT, it is easier to hear the “zizi” sound at the SPK output. Therefore, it is better to
connect in parallel with the input of the Audio PA in the schematic design. Some large capacitance
capacitors and series magnetic beads.
TDD and GND also have a great relationship. If GND is not handled well, many high-frequency
interference signals will interfere with MIC and Speaker through devices such as bypass capacitors, so
users should ensure good performance of GND during PCB design.
5.2.7. Other
The serial port interface of the module should also be kept as short as possible. It is best to walk in a
group when routing, and do not distract the wires.
6. Electrical & Reliability
6.1 Absolute Maximum
The table below shows the absolute maximum values that the module can withstand. Exceeding these
limits can cause permanent damage to the module.
Table 6.1: Absolute Maximum
Paramete
r
Minimum
Typical
Maximum
Unit
VBAT
-
-
6
V
VBUS
-
-
10.5
V
Peak
current
-
-
3
A
6.2 Working Temperature
The table below shows the operating temperature range of the module:
Table 6.2: Module Operating Temperature
Parame
ter
Minimum
Typical
Maximum
Unit
Workin
g
temper
ature
-25
-
75
℃