PCA9543A: the input rise/fall time of I2C in Timing Requirements

user6527039

Prodigy 70 points

Part Number: PCA9543A
Other Parts Discussed in Thread: TCA9539,

The requirement of input rise/fall time (ticr and ticf) of I2C is 20 + 0.1Cb to 300 ns in the datasheet.

I think there is no requirement on the minimum side in the I2C standard.

Why is it necessary for this IC?

What happen if the rise or fall time is lower than 20ns?

over 4 years ago

+1 Tyler Townsend over 4 years ago

TI__Guru 62928 points

Hello,

I found another forum post about a similar question for the TCA9539:

https://e2e.ti.com/support/interface-group/interface/f/interface-forum/723840/tca9539-i2c-input-rise-and-fall-time-for-fast-mode

The PCA9543A should work below minimum rise time spec in the datasheet. The datasheet goes off of the I2C standard for timing parameters for fast-mode operation. I believe that there is a minimum rise time spec because it helps to lessen EMI.

A rise time that is lower than 20ns should be okay for this device.

Regards,

-Tyler

Interface

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PCA9543A: the input rise/fall time of I2C in Timing Requirements