Product Info

Automotive Module Series

AG35 Hardware Design

AG35_Hardware_Design 51 / 129

 Keep the placement of (U)SIM card connector as close as possible to the module. Keep the trace

length as less than 200mm as possible.

 Keep (U)SIM card signals away from RF and VBAT traces.

 Assure 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 with parasitic

capacitance not exceeding 10pF. The 0Ω resistors should be added in series between the module

and the (U)SIM card connector so as to suppress EMI spurious transmission and enhance ESD

protection. The 33pFcapacitors are used for filtering interference of EGSM900. 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 occasions are applied, and should be placed close to the (U)SIM card connector.



The load capacitance of (U)SIM interface will affect rise and fall time of data exchange.

3.10. USB Interface

AG35 contains one integrated Universal Serial Bus (USB) interface which complies with the USB 2.0

specification and supports high-speed (480Mbps) and full-speed (12Mbps) modes. The USB interface is

used for AT command communication, data transmission, GNSS NMEA sentences 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

USB connection detection

Typical 5.0V

Maximum current: 1mA

USB_DM

USB differential data bus (-)

Require differential

impedance of 90Ω

USB_DP

USB differential data bus (+)

GND

Ground

For more details about USB 2.0 specifications, please visit http://www.usb.org/home.

NOTE