ISO1540: ISO1540 Connection Diagram

Mehmet Kilerci

Part Number: ISO1540

Tool/software:

Hi,

In application, there are two different GND levels and two ICs. We want to connect these two IC's to just one I2C line. Can we use ISO1540 in this configuration as shown below?

Best regards.

8 days ago

+1 Varun Kumar 8 days ago

TI__Intellectual 1965 points

Hi Mehmet,

Thanks for reaching out.

The Above Application should work Just fine with ISO1540.

Few things that you need to take care and change:

SDA1/SCL1 side is a single node side, recommended to be connected to master MCU. Please Refer this FAQ Post: (+) [FAQ] ISO1640: Why are the maximum load capacitance and load current ratings for Side 1 of the ISO1640/ISO1641 less than Side 2? - Isolation forum - Isolation - TI E2E support forums
VOL1(max) is 0.8V, so the logic compatibility between Side1 I2C device and ISO1540 needs to be verified before using datasheet VIL(min) values of Side1 I2C device. Refer this post to understand the device working and architecture better: (+) [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? - Isolation forum - Isolation - TI E2E support forums

Regards

Varun

0 Mehmet Kilerci 7 days ago in reply to Varun Kumar

Prodigy 20 points

Hi Varun,

Thanks for your response.

Best regards.

Isolation

Isolation forum

ISO1540: ISO1540 Connection Diagram