N27 Hardware User Guide
Chapter 4 Application Interfaces
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The following figure shows the reference design of the I2C interface.
Figure 4-18 Reference design of the I2C interface
I2C_SCL
I2C_SDA
DATA
SCL
I2C device
N27 module
VDD_1P8
2.2k
Ω
2.2k
Ω
Schematic guidelines:
The I2C interface should be pulled up. If the logic levels of the master and the slave are
inconsistent, add a level shifting circuit.
Do not cross other traces if possible. If crossing is inevitable, route the I2C traces perpendicular
to other traces.
Keep traces far away from areas that might introduce ESD.
Surround the traces with the ground plane if possible.
4.4 RF Interface
Signal
Pin
I/O
Function
Remarks
ANT
59
2G/4G antenna
50Ω impedance
ANT_GNSS
71
GNSS antenna
4.4.1 ANT Interface
ANT of N27 requires
a characteristic impedance of 50 Ω. You should control the impedance of the
traces between the pins and antenna to ensure the RF performance. An impedance matching circuit,
such as the L network, split capacitor network, and pi network is mandatory in between. Pi network is
recommended.
