Usb Interface - Quectel SC20 Series Hardware Design

3.9. USB Interface

SC20 series contains one integrated Universal Serial Bus (USB) interface which complies with the USB
2.0 specification and supports high-speed (480 Mbps) and full-speed (12 Mbps) modes. The USB
interface is used for AT command communication, data transmission, software debugging and firmware
upgrade.
The following table shows the pin definition of USB interface.
Table 11: Pin Definition of USB Interface
Pin Name Pin No.
USB_VBUS 141, 142
USB_DM 13
USB_DP 14
USB_ID 16
USB_VBUS can be powered by the USB power or adapter. It can be used for USB connection detection,
as well as for battery charging via the internal PMU. The input voltage of power supply ranges from 4.35 V
to 6.3 V, and the typical value is 5.0 V. SC20 series supports charging management for a single Li-ion
battery, but different charging parameters should be set for batteries with different models or capacities.
The module is available with a built-in linear-charging circuit which supports maximally 1.44 A charging
current.
SC20_Series_Hardware_Design
I/O Description
USB 5 V power input and USB
PI
insertion detection
AIO USB 2.0 differential data (-)
AIO USB 2.0 differential data (+)
AI USB ID detect
Smart Module Series
Comment
Vmax = 6.3 V
Vmin = 4.35 V
Vnom = 5.0 V
Compliant with USB 2.0
standard.
Require differential
impedance of 90 Ω.
High level by default.
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