2.8 to 3.3 volt I2C translation using PCA9306. (Corrected post stating the part I want to use)

Tim Reilly94896

Other Parts Discussed in Thread: PCA9306

I need to level shift between 2.8 and 3.3 volts. I was planning on using a PCA9306. The 2.8V I2C signals are on SCL1 and SDA1. The way I read the data sheet is that I should have EN > 2.8 + .6 or 3.4 volts minimum in this case. Can I simply tie the EN to 5 volts in this case and set VREF2 = 3.3 Volts? It seems I really don't care about clamping on the 3.3 volt side in this case because the output voltage can't go above the pull up resistor source voltage on the 3.3 volt side of the translator.

Thanks,

Tim

over 13 years ago

0 Michael S over 13 years ago

TI__Mastermind 21285 points

Customer issue has been resolved.

0 Andre over 10 years ago in reply to Michael S

Prodigy 40 points

Hi,

Can you elaborate on the resolution? We're tackling the same issue (2V8 <=> 3V3) and suspect the part to hang the bus very infrequently. We have EN connected to 3V3 via the 200KOhm resistor.

Regards,

Andre

0 Michael S over 10 years ago in reply to Andre

TI__Mastermind 21285 points

Hi user4448533 (might want to change that in your profile). Welcome to the E2E forums.

When posting a response, please be aware of a thread's age before posting a reply. If there is not a recent and active thread that discusses your issue, please feel free to create a new thread and refer back to the older one.

The problem was that VREF2 was not 0.6V higher than VREF1. This requirement is mentioned in section 9.2.1 of the device datasheet and is expanded upon, along with the requirement of the Rpu at the EN/VREF2 node, in this post.

0 Andre over 10 years ago in reply to Michael S

Prodigy 40 points

Thank you Michael.

Andre

0 Jonathan Valdez over 10 years ago in reply to Andre

TI__Genius 16510 points

Andre,

I would also like to point out that if you have another question or issue you'd like help with, please feel free to post in the I2C forum that we are in currently (The PCA9306 is supported in this forum by me), and I will be happy to help you.

Interface

Interface forum

2.8 to 3.3 volt I2C translation using PCA9306. (Corrected post stating the part I want to use)