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LTE-A Module Series
EG18 Hardware Design
EG18_Hardware_Design 47 / 104
Keep (U)SIM card signals away from RF and VBAT traces.
Keep the ground traces between the module and the (U)SIM card connector short and wide. Keep
the trace width of ground and USIM_VDD no less than 0.5mm to maintain the same electric potential.
To avoid cross-talk between USIM_DATA and USIM_CLK, keep them away from each other and
shield them with surrounded ground.
To offer good ESD protection, it is recommended to add a TVS diode array with parasitic capacitance
not exceeding 50pF. The 22
Ω resistors should be added in series between the module and the
(U)SIM card connector to facilitate debugging. Please note that the (U)SIM peripheral circuit should
be close to the (U)SIM card connector.
The pull-up resistor on USIM_DATA line can improve anti-jamming capability when long layout trace
and sensitive occasion are applied, and should be placed close to the (U)SIM card connector.
3.9. USB Interface
EG18 provides one integrated Universal Serial Bus (USB) interface which complies with the USB 3.0 and
USB 2.0 specifications. It supports super speed (5Gbps) on USB 3.0 and high speed (480Mbps) and full
speed (12Mbps) modes on USB 2.0. The USB interface is used for AT command communication, data
transmission, GNSS NMEA sentence output, software debugging, firmware upgrade, and voice over
USB*.
The following table shows the pin definition of USB interface.
Table 11: Pin Definition of USB Interface
Pin Name
Pin No.
I/O
Description
Comment
USB_VBUS
32
DI
Used for detecting the USB connection
Typical 5.0V
USB_DP
34
IO
USB 2.0 differential data bus (+)
Require differential
impedance of 90Ω
USB_DM
33
IO
USB 2.0 differential data bus (-)
USB_SS_ TX_M 37
AO
USB 3.0 super-speed transmission (-)
Require differential
impedance of 90Ω
USB_SS_ TX_P
38
AO
USB 3.0 super-speed transmission (+)
USB_SS_ RX_P
40
AI
USB 3.0 super-speed receiving (+)
Require differential
impedance of 90Ω
USB_SS_ RX_M 41
AI
USB 3.0 super-speed receiving (-)
USB_ID
36
DI
OTG identification
1.8V power domain.
If unused, keep it open
OTG_PWR_EN
143
DO
OTG power control