AnsweredAssumed Answered

I2C rise time at 100KHz (ADT7410)

Question asked by kc996 on Apr 9, 2015
Latest reply on Apr 9, 2015 by Lluis

Hi

We are using the ADT7410 on an I2C bus with several other I2C devices.
Our bus runs at 100 KHz (standard mode).
The SCL/SDA rise time for ADT7410 is quoted at 0.3uS for 0-400Hz on the
datasheet.
All of our other I2C devices and indeed the I2C standard quote a rise time of
1uS for 0-100KHz and 0.3uS for 100-400Khz.
Our bus currently has a rise time of 0.5uS approx which technically is out of
spec for the ADT7410.
My question is therefore for 100Khz operation does sthe ADT7410 still require a
rise time of 0.3uS? or can it tolerate up to 1uS as the I2C standard states?


I saw a very similar query answered on another Analog part which stated that it did need 0.3uS at all frequencies.
If the ADT7410 does indeed need a rise time of 0.3uS at 100KHz then the device does not comply with the I2C standard.

 

I realise stronger pull ups would fix the issue but surely the device must comply with the standard?
Thanks Kevin.

Outcomes