User's Manual

LTE

Module BEC CBRS-12 User Manual

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 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.

3.10. USB Interface

BEC CBRS-12 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 - plus

Require differential

impedance of 90Ω

USB_DM 33 IO USB 2.0 differential data bus - minus

USB_SS_ TX_M

37 AO

USB 3.0 super-speed transmission -

minus

Require differential

impedance of 90Ω

USB_SS_ TX_P

38 AO

USB 3.0 super-speed transmission -

plus