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Hello, I am using the CY7C65213-28PVXIT on my new PCB design. I want to configure the bridge for USB Bus Powered. I have looked on page 15 Figure 15 and would like to know it it is okay to filter the VBUS power that is connected to VCC and VCCIO?
Thank you
Joe
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Hello,
The schematic looks fine.
Optionally, if you want to reset the device using a hardware switch (push button), you can connect a pull up resistor to VCCIO and a capacitor to ground to met the 1us reset condition. Please refer to point 7 in this KBA: USB-Serial: Hardware Design Schematic Checklist - KBA231249
Thanks,
Yatheesh
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Hi,
It is okay to filter the VBUS power connected to VCC and VCCIO.
Please refer to the CYUSBS232 RDK schematics for reference https://www.cypress.com/file/123296/download
Also, please note that there should be a 0.1uF decoupling capacitor before both the VCC and VCCIO pins close to the IC. There should be no capacitors before the choke.
Please follow the schematics shared above.
Best Regards,
Mallika
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Hello, thank you very much for responding to my message. I noticed that VCCIO is from a Linear (U3) with Vin VBUS. What is the output voltage of U3? Do recommend I do the same on my schematics?
Thank you
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Hello,
VCCIO directly drives the IO pins and hence is recommended to be regulated.
Typical values for VCCIO is 1.8V and 3.3 V as mentioned in the CY7C65213 datasheet ,Table 3.
You can use a regulator to output 3.3V to VCCIO.
If you want to use 1.8V IO signaling (i.e. VCCIO = 1.8V), you need to remove the decoupling capacitor on VCCD and short VCCIO to VCCD.
Refer to VCCD pin Details column in CY7C65213 datasheet, Table 3. DC Specifications.
Thanks,
Yatheesh
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Hello, well if I open my eyes and read the datasheet then it will tell me that Vref if between 1.165 and 1.235 and using the equation for Vout I get 3.33V.
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Hello,
Yes 3.33 V is fine. You can regulate VCCIO to any voltage as per your requirement ( between VCCIO min and Max values mentioned in the datasheet).
We only recommend to regulate the VCCIO pin voltage so that any variations in supply will not affect the IO pin voltages as the VCCIO drivers the IO pins directly (not internally regulated).
3.3V and 1.8V recommendation was from the typical values in the datasheet.
Thanks,
Yatheesh
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Hello, thank you for responding to my question. I have added the regulator:
How do things look now? Any Red Flags?
Thank you
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Hello,
The schematic looks fine.
Optionally, if you want to reset the device using a hardware switch (push button), you can connect a pull up resistor to VCCIO and a capacitor to ground to met the 1us reset condition. Please refer to point 7 in this KBA: USB-Serial: Hardware Design Schematic Checklist - KBA231249
Thanks,
Yatheesh
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Hello, thank you very much for looking over my schematics and mentioning the reset. I will keep things as is.
Thank you and have a Happy New Years!