TUSB322I: I2C VIH/ VIL for pull high 5V application

Ben Kuo

Part Number: TUSB322I

Tool/software:

Hi Team,

We can found I2C VIH/VIL data from datasheet, but only find it in 1.8V~3.3V. Could you share VIH/VIL for 5Vcc application?

Per my understood, VIH should be (~0.7) *Vcc and VIL should be (~0.3)*Vcc.

Please share more detail with us. Thanks.

Regards,

Ben

11 months ago

0 J 11 months ago

TI__Genius 13266 points

Hi Ben,

For 5 Vcc application, the device still supports up to 3.3V I2C per datasheet. Therefore, I2C pullup will have to be to 3.3V.

Thanks,

0 Ben Kuo 11 months ago in reply to J

TI__Expert 7570 points

Hi J,

In datasheet, I2C can support up to 5V(section 6.3). And also in Intel CRB, they recommend customer to pull up to 5V.

Could you help to double confirm if I2C pull high cab be up to 5V or not?

Regards,

Ben

0 Clemens Ladisch 11 months ago

Guru 317080 points

The I²C switching levels are designed to be compatible with 1.8 V, regardless of the supply (so V_IL is very low). You can pull them up to a higher voltage, but the absolute maximum ratings and the recommended operating conditions contradict each other. Anyway, with V_DD = 5 V, you can pull up to 5 V.

0 Liang Tsai 11 months ago in reply to Clemens Ladisch

TI__Expert 4890 points

Hi Clemens,

To clarify, if I pull the I2C level to 5V, the VIH and VIL level would still stick with the specification for 3.3V in the data sheet?

Best,

Liang Tsai

0 J 11 months ago in reply to Liang Tsai

TI__Genius 13266 points

Hi Liang,

I am consulting my coworker on this so I will get back to you once I hear back.

Best,
J

0 David (ASIC) Liu 11 months ago in reply to J

TI__Guru**** 177476 points

Ben

Section 6.3 defines the voltage range when SCL/OUT2 and SDA/OUT1 are OUT1 and OUT2 signals. If you look at section 6.5, it states that I2C voltage range is from 1.65V to 3.6V.

Thanks

David

0 Liang Tsai 11 months ago in reply to David (ASIC) Liu

TI__Expert 4890 points

Hi David,

Thanks for the clarification. However, I am still unclear about which data in the data sheet to follow for the I2C voltage. Is it 3.6v or 5V? If it could only pull to 3.6V Max, why intel CRB recommends to pull up to 5V.

Thanks for the support!

Best,

Liang Tsai

0 Liang Tsai 11 months ago in reply to Liang Tsai

TI__Expert 4890 points

Hi David,

Any update on this?

Best,

Liang Tsai

0 J 11 months ago in reply to Liang Tsai

TI__Genius 13266 points

Hi Liang,
You can only pull up to the 3.3V, because TUSB322I was designed to support up to 3.3V I2C. The datasheet also says 5V max because those pins are used for GPIO mode (as OUT1 and OUT2) and in that case you can support up to 5V. However, this is not the case on 12C mode.
Thank you.

Best,
Jae

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TUSB322I: I2C VIH/ VIL for pull high 5V application