I'm reading the datasheet of TCA9548A:


I'm confused about how the I_OL and I_I are defined. Any help and comments are welcome.



There's a screenshot of the Application Report: Understanding the I2C Bus enter image description here

Does the red arrow mean I_OL, which is at least 3mA? And I_I means the current into the pin when the MOSFET is off and there's no Pull-up resistor?


2 Answers 2


TI has descriptions of these electrical specifications in Understanding and Interpreting Standard-Logic Data Sheets.

\$I_{OL}\$: Low-Level Output Current (page 33)

The current into an output with input conditions applied that, according to the product specification, establishes a low level at the output

\$I_I\$: Input Current (page 44)

The current into an input (current into a terminal is given as a positive value)

  • \$\begingroup\$ Hi. Thanks for your answer. I edited my question. Can you say if my understanding is right? \$\endgroup\$
    – vvttr
    Commented Oct 30, 2023 at 16:11
  • \$\begingroup\$ @vvttr: You're welcome. You should have opened a new question instead of editing this question to ask a new question. Since you are a new user: What should I do when someone answers my question? \$\endgroup\$
    – toolic
    Commented Oct 30, 2023 at 16:25

Iol is how much the chip can sink current on SDA, which means when communicating with the chip itself.

It means that the chip conforms to the standard [email protected] and also able to drive full bus load at 400 kHz which requires [email protected].

Ii is the leakage current of all the listed pins when either connected to GND or supply.

These are defined under 1.65V to 5.5V supply and other default conditions unless otherwise mentioned.

  • \$\begingroup\$ Hi. Thanks for your answer. I tried to understand what you mean. Can you tell me if my understanding is right? \$\endgroup\$
    – vvttr
    Commented Oct 30, 2023 at 16:12
  • \$\begingroup\$ @vvttr Almost right. Yes the 3mA relates to the FET when it is active. Thr 1uA relates to when the chip is not active, but the bus is high due to pull-up or low due to some other chip pulling down, be it the master or another slave. \$\endgroup\$
    – Justme
    Commented Oct 30, 2023 at 16:36

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