UM220-IV NL User Manual
10
4
Hardware Design
4.1
Design in Considerations
To ensure that UM220-IV NL works properly, please pay attention to the following:
Recommended to connect 1 K
Ω
resistance at RX serial ports, and 33 Ω or 1 KΩ
resistance at TX serial ports; other necessary PIOs require 4.7 KΩ resistance
connected in series at the pin. The resistance can be adjusted slightly according
to the application to achieve better effect.
Connect all the GND pins to ground.
Connect the RF_IN signal to the antenna, and the line should keep 50Ω impedance
matching.
Ensure COM1 is connected to a PC or an external processor. Users can use this
serial port to receive position data. COM1 is also necessary for firmware upgrades.
In order to obtain good performance, special concern should be paid during the design
：
Power supply: Stable and low ripple power is necessary for good performance.
Make sure the peak to peak voltage ripple does not exceed 50mV.
−
Using LDO to ensure the purity of power supply
−
Try to place LDO close to the module in layout
−
Widening the power circuit or use copper pour surface to transmit current
−
Avoid wiring through any high-power or high inductance devices such as
magnetic coils
UART interfaces: Ensure that the signals and baud rate of the main equipment
match that of the UM220-IV NL module
Antenna interface: Make sure the antenna impedance matching, and the circuit is
short and smooth; try to avoid acute angles
Antenna position: In order to ensure a good signal-to-noise ratio, the antenna is
required to be well isolated from any electromagnetic radiation source, especially
the electromagnetic radiation in the frequency range of 1559 ~ 1607MHz
Try to avoid circuits below UM220-IV NL
This module is a temperature sensitive device and dramatic changes in
temperature will result in reduced performance, so keep it as far away from any