ISO1540: SDA / SCL connect

Hello Ishiwata,

Thanks for reaching out.

Both SDA and SCL are bidirectional in nature in ISO1540 and ISO1640. Which means that yes you can connect in above configuration.

You're planning to use this specifically for I2C communication right?

Regards
Varun

Hi Ishiwata,

Shuji Ishiwata said:

(1) I am assuming a connection configuration where Side 1 is the SLAVE and Side 2 is the MASTER.　
In the datasheet below, it says that when Side 1 is the MASTER and Side 2 is the SLAVE, it performs optimally.
What concerns or effects would there be if Side 1 were the SLAVE and Side 2 were the MASTER?

This is because ISO1640 can have only one node connected to Side1 and including the bus cap limitation of 40pF - it is recommended to have Master on Side1 in a typical multi slave operation

If you have single SLAVE device then either way will work

Shuji Ishiwata said:

(2) I understand that SCL and SDA have exactly the same characteristics, but is that correct? Are there any differences

Yes, that is correct but only for a particular side. Side1 SDA/SCL is different from Side2 SDA/SCL. Refer Section 8.5 for details on this.

You can also our FAQ : https://e2e.ti.com/support/isolation-group/isolation/f/isolation-forum/757564/faq-why-is-the-logic-low-level-output-voltage-vol1-up-to-0-8v-on-side1-of-the-iso1540-iso1541-and-iso1640-iso1641-bidirectional-i2c-isolators

Shuji Ishiwata said:

(3) In 9.2.2 Detailed Design Procedure, it says 0.1uF, but the circuit diagram says 0.01uF.
Which is correct?

The minimum value and the correct value is 0.1uF. 

You can refer to EVM Schematics and Layout for your reference : https://www.ti.com/lit/ug/sllu322a/sllu322a.pdf?ts=1752830138710&ref_url=https%253A%252F%252Fwww.ti.com%252Ftool%252FISO1640EVM

Regards
Varun