• State
  • Locked Locked
  • Replies 3 replies
  • Subscribers 16 subscribers
  • Views 1072 views
  • Users 0 members are here
Support feedback
Options
Options
Similar topics

This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

Bidirectional digital isolation

David Garcia53
Prodigy 20 points
Other Parts Discussed in Thread: ISO1540

Other than a I2C isolation device (ISO1540), I can't seem to find any other bidirectional isolation IC.  I need to isolate serial 1-Wire com lines, and don't believe the ISO1540 can handle straight digitally pulsed interface signals. 

Does anyone have any information on this issue?

  • 0
    TI__Intellectual 2855 points

    Hi David,

    To help you better with this query, can you please brief about your application?

    Please can you let us know the minimum VIL,VOL and maximum VIH,VOH threshold voltages  of the comm lines in the system?

    Regards

    Tejas 

  • 0 in reply to Tejas Hommaradi
    Prodigy 20 points

    Hello Tejas,

    The specifications for the comm line is based on requirements of the Dallas Semiconductor DS2505 EPROM.  Unfortunately, I couldn't attach the pdf of the datasheet, but it should be readily available online.

    Thanks

    David

  • 0 in reply to David Garcia53
    TI__Intellectual 2855 points

    Hi David,

    One side of ISO1540 is DS2505, and what is on the other side of ISO1540? 

    Based on DS2505 data sheet I have calculated the following to see if DS2505 and ISO1540 are compatible.

    For the scenario where ISO1540 is sending data out and DS2505 is receiving: 

    The DS2505 input  VIL (max) and VIH (min) are 0.8V and 2.2V respectively. The VOL (max)  of ISO1540 output (side 2) is 0.4V and  VOH is VCC - voltage drop across the pull up resistor. So it can be made compatible by carefully selecting the pull up resistor value.

    For the scenario where DS2505 is sending data out and ISO1540 is receiving: 

    The DS2505 output VOL(Max) and VOH (Typ)  is 0.4V and 2.8V respectively. The VIL(max) and VIH(min) of ISO1540 (side 2) is 0.3*VCC2 and 0.7*VCC2

    assuming 3.3V supply to ISO1540 the  VIL(max) and VIH(min) will be 0.99V and 2.31V respectively. looks compatible with 3.3V supply.

    These calculations are for communication, this will not support programming of DS2505 and also we have to similarly check the voltage thresholds of the device on side 1 of ISO1540 before we conclude.

    Regards

    Tejas