UM4B0 User Manual
8
3
Hardware Design
3.1
Design in Considerations
To make UM4B0 work properly, you need to properly connect the following:
The module VCC power-on behavior is repeatable, the initial level is lower than
0.4V, and the undershoot and ringing should be guaranteed to be within 5% VCC
Provide stable power to the VCC pin
Connect all the GND pins to ground
Connect VBAT pin to a 3.0V power supply
Connect ANT_IN signal to the antenna, and ensure the 50-ohm impedance
matching
Connect ANT_PWR to +3.3~5.5 V voltage, then 3.3~5.5 V feed to the
antenna through ANT_IN
Ensure COM1 is connected to a PC or an external processor, and users can use
this serial port to receive position data. COM1 is also necessary for firmware
upgrades
Properly connect the module’s reset pin FRESET_N to ensure complete reset of
the module. It will restore the module to the manufacturing configuration.
When ANT_NLOD, ANT_FFLG and antenna detection indication signal are
connected, the IO without any pull-up/down of the client MCU terminal is
required at the input.
In order to obtain proper performance, special concerns should be paid during the
design:
Power supply: A table and low ripple power supply is necessary for good
performance. Make sure the peak-to-peak voltage ripple does not exceed
50mVpp. It is recommended to use a power chip with current output capacity
greater than 2A to power the board.
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Use LDO to ensure the purity of power supply
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Try to place LDO close to the module in layout
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Widen the tracks of power circuit or use copper pour surface to transmit
current
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Avoid walking through any high-power or high inductance devices such as a
magnetic coil
