User's Manual

MB1749 hardware
UM2358-1
5
MB1749 hardware
5.1
ST25R3916B
The ST25R3916B is directly connected to the filtered 5 V USB supply. There are additional
supply filtering components placed close to the NFC/HF reader IC.
During layout all decoupling capacitors have been placed as close as possible to the
ST25R3916B chip.
For SPI cross-connecting another reader PCB, serial resistors can be removed and CN100
used.
By default, the SPI is the firmware and hardware access bus. The I2C bus can be used
instead by changing J200, J201, J202, J203, J204 and J205.
J206 makes it possible to bypass the internal V
current higher than 350 mA needs to be supported.
/ V
DD_AM
regulators when an output
DD_RF
5.2
Antenna and matching network components
This board contains the matching network and the automatic antenna tuning capacitors
based on varicap.
12/31
UM235x Rev 02