The voltage range of the Open drain pin


Does VDD_IN apply to the VDD included in the provisions described in the following data sheet?
If this is the case, then the minimum value of Vih will exceed the maximum value when VDD_IN(=5V).
How should I understand this?

Best Regards,

It is for 3.3 OD pin as the maximum value is 3.3+10%.

Do you mean VDD=3.3V?
Also, is this stated on NVIDIA’s documentation?

Yes, I mean the VDD is 3.3v in max in your picture.
If VDD is 5V in max and the pin is for 5V level, then it should be 5.5v in max in the table.

This table says that the maximum value of Vih is 3.63, which is wrong, and VDD+10% is actually correct?

Hi Trumany,

Could you please comment on Vih’s max value?

Best Regads,

Hi, please find below detail comments from our team:

  1. The “VDD” referenced in Table 34: Open Drain Pin Type DC Characteristics is referring to the power supply of the corresponding IO rail. You would need to look in the PinMux spreadsheet to see how we’ve connected VDD for that specific pin, i.e. there are groups of pins that each have their own corresponding VDD.
  2. Ordinarily the min and max ranges are given with respect to VDD. However, these open drain pins are special. They are designed to be 3.3V tolerant. In other words, despite the voltage being 1.8V, you can still safely pull it to 3.3V (with proper software configuration). The 3.63V gives you 10% margin to account for any power supply ripple, etc.
  3. In order for the pin to correctly function as 3.3V tolerant, there is a corresponding bit in the pinmux register that needs to be enabled. This is shown in the spreadsheet in the “3.3V Tolerance Enable” column. If the IO rail is 1.8V and you inputting a 3.3V signal (like the I2C), then you should set this bit.

Example 1:
• Look at pins 185, 187 in Xavier NX spreadsheet (Signal Names I2C0_SCL, I2C0_SDA).
• These pins are under a 1.8V header, meaning the module has their corresponding VDD connected to 1.8V.
• Table 17 of the data sheet mentions these are pulled up to 3.3V on module.
• Consequently the spreadsheet enables 3.3V tolerance for their pins because they have VDD=1.8V, but connect to 3.3V.

Example 2:
• Look at pins 232, 234 in Xavier NX spreadsheet (Signal Names I2C2_SCL, I2C2_SDA).
• These pins are also under a 1.8V heading, i.e. their VDD=1.8V.
• Table 17 of the data sheet mentions these are pulled to 1.8V.
• We do NOT want to set the 3.3V tolerance in this case. That is only used in the case where VDD=1.8V and you are connecting to 3.3V.

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