Usb Interface - Quectel UC20 Manual

3.12. USB Interface

UC20 contains one integrated Universal Serial Bus (USB) transceiver which complies with the USB 2.0
specification and supports high speed (480 Mbps), full speed (12 Mbps) and low speed (1.5 Mbps) mode.
The USB interface is primarily used for AT command, data transmission, GNSS NMEA sentences output,
software debug and firmware upgrade. The following table shows the pin definition of USB interface.
Table 15: USB Pin Description
Pin Name Pin No.
USB_DP 69
USB_DM 70
USB_VBUS 71
GND 72
More details about the USB 2.0 specifications, please visit http://www.usb.org/home.
The following figure shows the reference circuit of USB interface.
USB_VBUS
USB_DM
USB_DP
GND
Module
UC20_Hardware_Design
I/O Description
IO USB differential data bus (positive).
IO USB differential data bus (minus).
Used for detecting the USB interface
PI
connected.
Ground.
Differential layout
Figure 26: Reference Circuit of USB Application
Confidential / Released
UMTS/HSPA Module Series
Close to USB connector
NM_2pF
ESD Array
UC20 Hardware Design
Comment
Require differential
impedance of 90Ω.
Require differential
impedance of 90Ω.
3.0~5.25V.
Typical 5.0V.
USB_VBUS
USB_DM
USB_DP
GND
USB connector
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