STUSB02E datasheet(15/20 Pages) STMICROELECTRONICS

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STUSB02E

7 Functional Description

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Functional Description

The STUSB02E is designed to provide USB connectivity in portable systems where available system

supply voltages are not able to satisfy USB requirements. The STUSB02E can operate down to supply

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

STUSB02E 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+ or

D– lines to respectively specify full speed or low speed operation.

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

STUSB02E 数据表(PDF) 15 Page - STMicroelectronics