UM220-IV M0 User Manual
8
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Try to place LDO close to the module in layout
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Widening the power circuit or use copper pour surface to transmit current
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Avoid walking through the high-power or high inductance devices such as
magnetic coil
UART interfaces: Ensure that the signals and baud rate of main equipment
match UM220-IV M0 module’s
Antenna interface: Make sure the antenna impedance matching, and the
circuit is short and smooth, try to avoid acute angle
Antenna position
：
In order to ensure a good signal-to-noise ratio, the
antenna is well isolated from the electromagnetic radiation source, especially
the electromagnetic radiation in the frequency range of 1559 ~ 1605MHz
Try to avoid circuits below UM220-IV M0
This module is a temperature sensitive device, dramatic changes in
temperature will result in reduced performance, keep it as far away from the
high-power high-temperature air and heating devices as possible.
4.2
Avoid Power Connection
Module input port (UM220-IV M0 including: RXD, GPIO) when the module is not powered
on, if there is data input in the above port, it will form a series of power on the module VCC.
When the series voltage is higher than 1.6V, it may cause the failure of starting up when
the module is powered on.
Solution
：
When the module is not powered on, make sure that the IO port connected by the
module is in a high-resistance state or a low level to avoid power connection. Or in the
serial concatenated 1KΩ resistor RX, TX concatenated 33Ω or 1K resistor, other need
PIO concatenated 4.7KΩ resistor in the Pin.
4.3
Antenna
If UM220-IV M0 used the +3V active antenna, suggest use the VCC_RF pin output is
recommended to power the antenna through feed inductance.
