VCCIO/VDDD Power Domain of USB-Serial Controllers – KBA89413 | Cypress Semiconductor
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VCCIO/VDDD Power Domain of USB-Serial Controllers – KBA89413
What precautions should you take when the VCCIO supply (for CY7C65213) or the VDDD supply (for CY7C65211 and CY7C65215) of the USB-Serial Bridge Controller device is connected to 2 V or less?
VCCIO/VDDD is the input supply to the USB-Serial Bridge Controller device Core and IO domains, and VCCD is the output of the internal voltage regulator. USB-Serial devices support a voltage range from 1.71 V to 5.5 V on the VCCIO/VDDD supply.
If the VCCIO/VDDD supply is 2 V or less, connect the VCCD to VCCIO/VDDD. You also need to select VDDD is less than 2 V while configuring the device using the USB-Serial Configuration Utility. For more details, please refer to Section 22.214.171.124.2, ”VDD is less than 2 V” of the Configuration Utility User Guide. You can download the Configuration Utility and its User Guide from the USB-Serial Software page.
For a VCCIO/VDDD supply greater than 2 V, decouple the VCCD pin to the ground with a 1 μF capacitor.