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[SOLVED] FT232RL wrong voltage at VCCIO and 3V3OUT pins

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estratos

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Similar to this user:
https://www.edaboard.com/threads/210881/

I'm having problems with a custom FT232RL board. I've designed lots of FT232-based boards in the past, but always with an additional LDO to power my MCU from Vbus (5V). This time I want the FT232RL to power my MCU from its internal 3.3V LDO but voltage at the VCCIO and 3V3OUT pins is higher than that:

With my MCU board unplugged: VCCIO = 3.3VOUT = 4.1 V
With my MCU board plugged: VCCIO = 3.3VOUT = 3.8 V

Apart from this issue, the board is working well (USB comms, UART comms, LED's, etc).

This is my circuit:
FT232RL.png

100nF decoupling capacitors are close to VCCIO and 3V3OUT pins. Additionally, I've tried placing some other values like 10uF and 1uF but nothing changes.

Thanks guys for your feedback!
 
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estratos

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FYI, I've found where the problem is. My FTDI IC's where bought from an eBay store, all showing a ref number "0550-A". Well none of these chips are able to regulate to 3.3V. Using new FT232RL IC's purchased from Mouser solved the problem.
 

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