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ISO1540: Lower VIL Alternative Solution

Jim CHEN
Expert 4795 points

Part Number: ISO1540
Other Parts Discussed in Thread: PCA9306, PCA9515, LSF0102

Dear Team,

My customer's I2C architecture is as below block diagram.

They found that ISO1540's VIL spec is maximum 0.5V, they want to know if there is any other solution that has lower VIL than 0.5V to replace ISO1540.

Do you have any suggestion or advice?  

Thank you.

Regards,

Jim

  • 0
    Guru 325100 points

    The ISO1540 will work with any low-level input voltage below 0.5 V. Why would you want a lower VIL limit? Is the question about some VOL? What is the actual problem the customer is trying to solve?

  • 0
    TI__Guru 57145 points

    Hi Jim,

    Thanks for sharing the block diagram.
    I am not sure if I understand the requirement correctly. ISO1540 SDA1 & SCL1 pins have a VOL spec of max 0.8V and we usually see customers asking if we have a device with lower VOL spec. Is this also what your customer is looking for? Does your customer require ISO1540 VOL to be <0.5V?

    On the other hand, VIL spec is usually preferred to be higher. The device has a VIL max spec of 0.5V and it is preferred to have a higher VIL max like 0.8V, 1V or even 0.3*VCC.

    Please do share customer schematic showing all the above 4 devices and also showing the devices connected to the other side of LSF0102, PCA9306 and PCA9515 so that I can check their input and output thresholds and comment if this is going to work fine.

    Please see below FAQ for more details on ISO1540 VOL spec, thanks..

    Regards,
    Koteshwar Rao

  • 0 in reply to Koteshwar Rao
    TI__Guru 57145 points

    Hi Jim,

    I hope your questions are answered. I will go ahead and close this post but if you do have further questions then do reply to this E2E post, thanks.

    Regards,
    Koteshwar Rao