USB 8451 I2C 3V3

[stevesteve]

I wish to communicate with a I2C device that uses 3V3 I2C levels. I know the USB 8451 will accept a 3V3 I2C input as a 'high' logic level, but can the USB 8451 provide a I2C output at 3V3 logic levels to the target device?

Do I need to add an external  voltage level shifter IC between the USB-8451 and the target I2C device?

[crossrulz · Accepted solution]

The 8451 does not have a build-in pull-up resistor.  So the voltage level will depend on whatever pull-up you have on the lines.  The 8451 just needs a voltage of at least 2V to register a high, with a maximum input voltage of 5.8V (but would not suggest exceeding 5.5V).