ISO122 Supply voltages

Can I use ISO122 with +Vs = 15V and -Vs = 0V/GND, for both sides input and Output. And if we can then is it possible to have Input voltage range upto 12.5V with these supplies?

3 Replies

  • Nilesh,

    A negative power supply is required on both input and output to handle input/output signals down to 0V. For signals ranging from 0V to 12.5V, I recommend a power supply of -5V and +18V on both input and output sides.

    Without negative supplies on input and output the lower end of the signal range would be approximately 3V.

    Regards, Bruce.

  • In reply to Bruce Trump:

    Hello Bruce, 

    Thank you. What is the level of isolation voltage(min. to max.) that we can have if we use ISO122 IC with 

    +Vs1=5V, -Vs1=GND1=0V and +Vs2=5V, -Vs2=GND2=0V. 

  • In reply to nilesh khupase1:


    The power supply voltage does not affect the isolation voltage capability of the ISO122. The isolation voltage rating is determined by the integrity of the insulating materials used between the input and output sections.

    The power supply voltages you propose will not allow the ISO122 to pass a signal. The minimum rated supply is +/-4.5V (or 9V, single supply). Signal swing capability with this minimum supply would be very limited.

    Regards, Bruce.