Usb Interface - Quectel LTE-A Series Hardware Design


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 22Ω 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.
USB_VBUS 32
USB_DP 34
USB_DM 33
USB_SS_ TX_M 37
USB_SS_ TX_P 38
USB_SS_ RX_P 40
USB_SS_ RX_M 41
USB_ID 36
OTG_PWR_EN 143
EG18_Hardware_Design
I/O Description
DI Used for detecting the USB connection
IO USB 2.0 differential data bus (+)
IO USB 2.0 differential data bus (-)
AO USB 3.0 super-speed transmission (-)
AO USB 3.0 super-speed transmission (+)
AI USB 3.0 super-speed receiving (+)
AI USB 3.0 super-speed receiving (-)
DI OTG identification
DO OTG power control
LTE-A Module Series
EG18 Hardware Design
Comment
Typical 5.0V
Require differential
impedance of 90Ω
Require differential
impedance of 90Ω
Require differential
impedance of 90Ω
1.8V power domain.
If unused, keep it open
47 / 104