Quectel EG25-G - USB Interface

LTE Module Series
EG25-G Hardware Design
EG25-G_Hardware_Design 43 / 100
3.10. USB Interface
EG25-G 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 10: Pin Description of USB Interface
Pin Name
Pin No.
I/O
Description
Comment
USB_DP
69
IO
USB differential data bus (+)
Require differential
impedance of 90Ω
USB_DM
70
IO
USB differential data bus (-)
Require differential
impedance of 90Ω
USB_VBUS
71
PI
USB connection detection
Typical 5.0V
GND
72
Ground
For more details about the USB 2.0 specifications, please visit http://www.usb.org/home.
The USB interface is recommended to be reserved for firmware upgrade in customers’ designs. The
following figure shows a reference circuit of USB interface.
USB_DP
USB_DM
GND
USB_DP
USB_DM
GND
L1
Close to Module
R3
R4
Test Points
ESD Array
NM_0R
NM_0R
Minimize these stubs
Module
MCU
USB_VBUS
VDD
Figure 19: Reference Circuit of USB Application