About ADUM2250 I2C isolator logic level

Hello Tarzan,

I am a little confused by your question.  The standard CMOS I/O levels are Hih =0.7xVdd and Vil=0.3xVdd  The Vil threshold to 3.3V is 0.99V which is sufficiently higher than the Vol generated by the ADuM125x on side 1.  Are you running non-standard logic levels?

Best regards,

MSCantrell

Hi MSCantr

Thanks for your reply.

I see your point.

This MCU has a couple of I2C ports and some I2C port is configured to I/O pin of 0.2V*Vdd and one I2C is 0.3V*Vdd.

I Just wonder what is the way to solve the level problem if ADUM2250 is used non-standard-logic level pins.

Best regards,

Tarzan

Hello Tarzan,

We have had customers use repeaters in the past.  They act like voltage translators in some respects.  You can also use the ADuM1250 and flip the chip around so the side 2 buffers face the low threshold component.  This only works if at least one of the sides of the bus conform to CMOS input levels.

Mark Cantrell

781-937-1486

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