BQ27520-G4: I2C communication speed

Masashi Mineda

Expert 1305 points

Part Number: BQ27520-G4

Tool/software:

Dear Sirs and Madams,

We are considering using the BQ27520-G4.

We would like to confirm the I2C specifications for communicating with an external MCU.

I have confirmed that the BQ27520-G4 datasheet specifies the I2C clock frequency as 400kHz (max).

In I2C fast mode, 400kHz operation is common, but I think that tolerances are taken into consideration.

For example, 400kHz +/- XX kHz

Is there any tolerance for error regarding this 400kHz (max)?

Regards,

Masashi

6 months ago

0 Alan Frias 6 months ago

TI__Mastermind 30810 points

Hello Masashi,

Could you specify what are you referring to as for "Tolerance for error regarding this 400kHz(max)".

Thank you,
Alan

0 Masashi Mineda 6 months ago in reply to Alan Frias

Expert 1305 points

Hi Alan,

The MCU and BQ27520 are connected via I2C, and the I2C SCL is generated from I2C Master of the MCU.

In this case, 400 kHz is used for the I2C Master's SCL, but this 400 kHz clock has some error.

The data sheet for the BQ27520 states that the frequency is 400 kHz (max), but is there any acceptable error?

For example,

I2C Master SCL of the MCU : 400kHz +/-3%

I2C Slave SCL of BQ27520 : 400kHz(max) *Does this mean that 400kHz + 3% is not acceptable?

Regards,

Masashi

+1 Alan Frias 6 months ago in reply to Masashi Mineda

TI__Mastermind 30810 points

Hello Masashi,

TI doesn't have a "% error" with its I2C since it follows the I2C protocol meaning that if you follow the standard practice with it than you shouldn't see any errors.

Thank you,
Alan

0 Masashi Mineda 6 months ago in reply to Alan Frias

Expert 1305 points

Hi Alan,

I have checked other I2C slave products such as BQ devices and ADCs, as well as the NXP I2C bus specifications, and understood your answer.

Regards,

Masasashi

0 Alan Frias 6 months ago in reply to Masashi Mineda

TI__Mastermind 30810 points

Hello Masashi,

Thank you for the feedback.

Regards,
Alan

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BQ27520-G4: I2C communication speed