LTE-A Module Series
EG12 Hardware Design
EG12_Hardware_Design 45 / 97
In order to enhance the reliability and availability of the (U)SIM card in applications, please follow the
criteria below in the (U)SIM circuit design:
Keep placement of the (U)SIM card connector to the module as close as possible. Keep the trace
length as less than 200mm as possible.
Keep (U)SIM card signals away from RF and VBAT traces.
Ensure that the ground 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.
In order to offer good ESD protection, it is recommended to add a TVS diode array of which parasitic
capacitance should be no more than 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.
3.10. USB Interface
EG12 provides one integrated Universal Serial Bus (USB) interface which complies with the USB 3.0 and
2.0 specifications. This USB interface supports super speed (5Gbps) on USB 3.0 and high speed (480
Mbps) and full speed (12 Mbps) modes on USB 2.0. It 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
PI
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