TPS6521855: I2C input capacitance

Kazuki Itoh

Genius 9175 points

Part Number: TPS6521855

Hi team,

Could you please let me know the I2C input capacitnce for the devices below?

1. TPS6521855

2. LP873345

My customer needs the value to simulate I2C signal integrity.

Best regards,

Itoh

over 1 year ago

0 James Steenbock over 1 year ago

TI__Genius 15085 points

Hi Itoh,

The capacitive load for each of the I2C bus lines for both the TPS6521855 and the LP873345 is 400pF.

For confirmation see Section 4.6 of the TPS6521855 datasheet and Section 6.6 of the LP8733xx datasheet.

Regards,

James

0 Kazuki Itoh over 1 year ago in reply to James Steenbock

TI__Genius 9175 points

Hi James-san,

My customer doesn't mean the capacity load requirement for the bus line.
They care about the actual input capacitance of each PMIC.
Generally it is supposed to be 10pF according to I2C standard (It can vary a little bit depending on ICs).

I have one more question.
Could you please let me know the current sink capability of SCL/SDA?
My customer would like to drive it with master x1 and slave x1, with 400kHz signal.
They need to adjust the pull-up resistance.

Regards,

Itoh

+1 James Steenbock over 1 year ago in reply to Kazuki Itoh

TI__Genius 15085 points

Hi Itoh,

The following images are the extent of the necessary information from the TPS6521855 datasheet. Specifications that are not included in the datasheet are not required for proper device operation.

We also have this documentation that discusses I2C bus capacitance in more detail (TI document):

https://www.ti.com/lit/pdf/scpa054

For more details on the LP8733xx device, I would recommend opening a separate E2E with the LP8733xx device tagged specifically.

Regards,

James

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TPS6521855: I2C input capacitance