OPT3001-Q1: Pull-up Bias for I2C

hideyuki sakai

Mastermind 6250 points

Part Number: OPT3001-Q1

Dear, Sir.

My customer is evaluating OPT3001-Q1 for their system, now.

They are making several questions as below.

Please give your advice.

1. They will supply 3.3V for OPT3001-Q1 and 5V will be supplied for

I2C pull-up bias source. I suppose this kind of usage will be no problem

because this device has "5.5V Tolerant I/O", but I would like to double-confirm

this. Is it no problem?

2. 3.3V will be OFF at system sleeping. 5V will continue to be supplied.

Is it no problem? They are concerning as the device break-down due to this

condition.

Best Regards,

H. Sakai

over 7 years ago

0 Alex Bhandari-Young over 7 years ago

TI__Mastermind 25895 points

Hi Hideyuki,

1. Yes this is okay, refer to the "Operating range of I2C pull-up resistor" spec in the electrical table of the datasheet
2. This will not damage the device, also see the same spec from 1, which says that VDD ≤ VI²C. However, the device will power off if 3.3V is lost so it will not be sleeping

Best,

Alex

0 hideyuki sakai over 7 years ago in reply to Alex Bhandari-Young

Mastermind 6250 points

Dear, Alex-san.

Thank you for your valuable advice.

You mentioned the device will not be sleeping even if 3.3V is OFF.
Does it means the device is still operating due to sneak current through pull-up
resistor from 5V?

Best Regards,
H. Sakai

0 Alex Bhandari-Young over 7 years ago in reply to hideyuki sakai

TI__Mastermind 25895 points

No device will be completely powered off.

Best,

Alex

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OPT3001-Q1: Pull-up Bias for I2C