Product Manual

13 INT - interrupt
14 NFC_3V3 - NFC power supply
15 KEY2 I
No connect
16 KEY1 I
No connect
4 Applications
4.1 NOTE
In order to ensure the RF performance of the module in the application to maximize its
effectiveness, users should follow the following rules in use
Principle:
1. The card searching distance can be adjusted by software;
2. The power supply capacity of the module must be greater than 200mA;
Using an internal LDO increases sensitivity, but system power consumption will be slightly
higher.
4.2 Reference manual
st25r3911b.pdf
5 Federal Communications Commission (FCC) Interference Statement
FCC Statement：
This device complies with part 15 of the FCC rules Operation is subject to the following two
conditions: (1) this device may not cause harmful interference, and (2) this device must accept
any interference received, including interference that may cause undesired operation.
NOTE: The manufacturer is not responsible for any radio or TV interference caused by
unauthorized modifications to this equipment. Such modifications could void the user’s
authority to operate the equipment.
NOTE: This equipment has been tested and found to comply with the limits for a Class B
digital device, pursuant to part 15 of the FCC Rules. These limits are designed to provide
reasonable protection against harmful interference in a residential installation. This equipment
generates uses and can radiate radio frequency energy and, if not installed and used in
accordance with the instructions, may cause harmful interference to radio
communications. However, there is no guarantee that interference will not occur in a
particular installation. If this equipment does cause harmful interference to radio or television