STUSB4500L Logic Voltage

dpcaffrey-kea · ‎2023-10-06

I am wondering what the logic voltage is for the I/O pins on the STUSB4500L. Under operating conditions they are listed as 0V to 4.5V, but the example circuit shows I2C pullup resistors to 3.3V. Is it safe to connect these I/O pins directly to a 3.3V logic level microcontroller, or will that require a level shifter?

TDK · ‎2023-10-09

They're open drain (OD) outputs, they're never driven high by the chip, they can only be driven low. You will need an external pullup in order to pull them up to 3V3 (or whatever).

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TDK · ‎2023-10-08

High/low digital input voltage thresholds are listed in the Electrical characteristics table. These pins are compatible with 0-3.3V logic.

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dpcaffrey-kea · ‎2023-10-09

Thank you for your response. When these pins are acting as outputs, will they drive the voltage higher than 3v3? I do not see a "High level output voltage" in the table you showed (or anywhere in the datasheet)

TDK · ‎2023-10-09

They're open drain (OD) outputs, they're never driven high by the chip, they can only be driven low. You will need an external pullup in order to pull them up to 3V3 (or whatever).

If you feel a post has answered your question, please click "Accept as Solution".

dpcaffrey-kea · ‎2023-10-09

Excellent, thank you for your help!