Usb Interface - Quectel UC15 Hardware Design

3.14. USB Interface

UC15 contains one integrated Universal Serial Bus (USB) transceiver which complies with the USB 2.0
specification and supports high speed (480Mbps), full speed (12Mbps) and low speed (1.5Mbps) mode.
The USB interface is primarily used for AT command, data transmission, software debug and firmware
upgrade. The following table shows the pin definition of USB interface.
Table 20: USB Pin Description
Pin Name Pin No.
USB_DP 62
USB_DM 63
USB_VBUS 64
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.
In order to ensure the USB interface design corresponding with the USB 2.0 specification, please comply
with the following principles.

It is important to route the USB signal traces as differential pairs with total grounding. The impedance
of USB differential trace is 90ohm.
UC15_Hardware_Design
I/O Description
IO USB differential data bus (positive).
IO USB differential data bus (negative).
PI USB detection.
Figure 34: Reference Circuit of USB Application
Confidential / Released
UMTS/HSDPA Module Series
UC15 Hardware Design
Comment
Require differential
impedance of 90Ω.
Require differential
impedance of 90Ω.
3.0~5.25V.
Typical 5.0V.
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