STUSB03EQR datasheet(15/20 Pages) STMICROELECTRONICS

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STUSB03E

Functional description

15/20

Functional description

The STUSB03E is designed to provide USB connectivity in mobile systems where available system

supply voltages are not able to satisfy USB requirements. The STUSB03E can operate down to supply

voltages of 1.6V and still meet USB physical layer specifications. As shown in the circuit above, the

STUSB03E takes advantage of the USB supply voltage, VBUS, to operate the transceiver. The system

voltage, VIF, is used to set the reference voltage used by the digital I/O lines interfacing to the system

controller. Internal circuitry provides translation between the USB and system voltage domains. VIF will

typically be the main supply voltage rail for the controller.

In addition, a 3.3V, 10% termination supply voltage, VPU, is provided to support speed selection. VPU can

be disabled or enabled under software control via the CON input. This allows for software-controlled

connect or disconnect states. A 1.5K resistor is required to be connected between this pin and the D- line

when operating in low speed mode. In full speed mode either an internal pull-up resistor or an external

one connected between VPU pin and D+ line can be used; the desired configuration is chosen by tying

RSEL pin to VIF or GND.

The use of ESD transient protection devices is not required for operation, but is recommended.

STUSB03EQR 데이터시트(PDF) 15 Page - STMicroelectronics