SN75DP139: I2C Port Driving Current issue

user4263714

Prodigy 120 points

Part Number: SN75DP139

SN75DP139 has a Sink and a Source I2C Port to connect with Master and Device.

So,What do this 2 Port Source current and Sink current?

The spec do not have these details

over 6 years ago

0 Michael.Walker over 6 years ago

TI__Mastermind 19720 points

The SN75DP139 I2C current for both will be 4 mA.

0 user4263714 over 6 years ago in reply to Michael.Walker

Prodigy 120 points

I think 4 mA is too small,the reason is HDMI spec shows SDA pullup resister between 1.5K~2K, and the display device SDA should have pullup resister to ensure the SDA rise time, if that, current is exceed the SN75DP139 sink current for 4mA,
Can u help to recheck it? thanks!

0 Michael.Walker over 6 years ago in reply to user4263714

TI__Mastermind 19720 points

4 mA is the correct because the 4 mA will drop the voltage on a 5V or 3.3V rail to zero as the picture below shows. The rise time does not depend on the current that the device's I2C can pull the rise time only depends of the RC time constant of the line.

Interface

Interface forum

SN75DP139: I2C Port Driving Current issue