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Power on FX3 CYUSB3014 | Cypress Semiconductor

Power on FX3 CYUSB3014

Summary: 1 Reply, Latest post by Dhritiman Kashyap on 11 Mar 2016 06:20 AM PST
Verified Answers: 0
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sanyahill_1599811's picture
9 posts


mine design progresses and the next challenge is the correct understanding of supply to the chip supply CYUSB3014. The Kit EZ-USB FX3  powered by USB bus or external power supply, such as the Spartan S601 Kit. My design has its own supply chain, all the necessary 5 V, 3.3 and 1.2 volts. In datasheet "EZ-USB FX3 Technical Reference Manual" on page 94 says: "1. Wait for a valid VBus voltage" and "Any PHYs that are enabled need to be disabled when the VBus voltage is removed. The entire previous procedure needs to be repeated when valid VBus is detected again" and "Note that USB 3.0 PHY on the FX3 needs to be turned off when VBus is removed or a host disconnect is discovered by other means. If the 3.0 PHY is left turned on, the 3.0 link startup is liable to fail when connected again to the host." What correctly is that mean? Can I supply only pin VBUS or VBATT (or both) from USB bus to comply with these requirements disable PHY when the device is not connected to USB, but other voltages (VIO[1..5], CVDDQ, VDD, AVDD, U3TXVDDQ/U3RXVDDQ) take from my power chain all time without interruption? Or I must take all voltages from VBUS by means of LDOs like in EZ-USB FX3 reference schematic?


kash's picture
Cypress Employee
112 posts


You should connect the VBUS pin of FX3 to the VBUS from the upstream. This is to detect host connection/disconnection. The rest of the supplies can be externally powered by using the external supplies you have on board.

You can refer to the schematics of the FX3 development kit (not the explorer kit !) for reference. Here you have the option to use a self powered design.

You can download the schematics here:






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