UM4B0 User Manual
9
3
Hardware Design
3.1
Design in Considerations
To make UM4B0 to work properly, you need to properly connect the following:
The module VCC power-on has good monotone, the initial level is lower than 0.4V,
and the undershoot and ringing should be guaranteed within 5% VCC
Provide reliable 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 make sure the 50 ohm impedance
matching
Connect ANT_PWR to +3.3~5.5 V voltage, then supply +3.3~5.5 V feed to the
antenna through ANT_IN
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
Properly connect the module’s reset pin FRESET_N to ensure reliable reset of the
module. It will restore to manufactory configuration.
When ANT_NLOD, ANT_FFLG and antenna detection indication signal are connected,
the IO of client MCU terminal is required as input without any pull-up/down.
In order to obtain proper performance, special concerns 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 50mVpp. It is
recommended to use a power chip with current output capacity greater than 2A to
power the board.
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Using 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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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
