Power on FX3 CYUSB3014 | Cypress Semiconductor
Power on FX3 CYUSB3014
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?