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with surrounded ground.
⚫
In order to offer good ESD protection, it is recommended to add a TVS diode array with parasitic capacitance
not exceeding 10 pF. The 22 Ω 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 33 pF capacitors 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.
⚫
NOTE
The load capacitance of (U)SIM interface will affect rise and fall time of the data exchange.
3.10. USB Interfaces
The module provides one USB 3.0 interface and one USB 2.0 interface which support SuperSpeed
USB 3.0) and High-Speed (480 Mbps on USB 2.0) modes.
The USB 3.0 interface is used for data communication with AP by default. The USB 2.0 interface supports AT
command communication, data transmission, software debugging, firmware upgrade and voice over USB*.
Table 12: Pin Description of USB Interface
Pin Name
Pin No.
USB_VBUS
84
USB_DP
85
USB_DM
87
USB_SS_TX_P
93
USB_SS_TX_M
91
USB_SS_RX_P
90
USB_SS_RX_M
88
It is recommended to reserve USB 2.0 for firmware upgrade in application design, and reserve test points for
debugging purpose. The following are the reference circuits of USB 3.0 and 2.0 interfaces.
AG521R-NA_QuecOpen_Hardware_Design
I/O
Description
DI
USB connection detect
AI/AO
USB differential data bus (+)
AI/AO
USB differential data bus (-)
AO
USB 3.0 super-speed transmit (+)
AO
USB 3.0 super-speed transmit (-)
AI
USB 3.0 super-speed receive (+)
AI
USB 3.0 super-speed receive (-)
Automotive Module Series
AG521R-NA QuecOpen Hardware Design
Comment
Compliant with USB 2.0
standard specification.
Require differential
impedance of 90 Ω.
Compliant with USB 3.0
standard specification.
Require differential
impedance of 90 Ω.
(5 Gbps on
50 / 92
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