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ISO1050 VI, VCANH, working insulation voltage, Isolation volatage

Other Parts Discussed in Thread: ISO1050

Hi team,

My customer wish to use ISO1050 in their 48V system, but they have some concern about the bus fault protection as the CANH/CANL cable may short to the power supply. So, would you please help with questions below? thanks.

1) the voltage range of Vi or Vic (voltage at bus pins, separately or common mode) is -12V~12V : is this means that when the voltage on CANH and CANL is within -12V~12V range, ISO1050 should be working correctly?

2) the VCANH or VCANL (Absolute Max Ratings, voltage range at any bus teminal) is -27V~40V: is this means that when the voltage on CANH and CANL is within -27~40V range, the CANH and CANL will not be damaged? will ISO1050 still working correctly when bus voltage is in this range (-27~-12V, +12V~+40V)? If not, what will happen? will the CAN controller receive any wrong data from ISO1050?

3) the working insulation voltage is 560V for ISO1050DUB and 1200V for ISO1050DW (use ISO1050DW 1200V as example): is this means that when the voltage on CANH and CANL is within 1200V range, the CANH and CANL will not be damaged? Will ISO1050 still working correctly when bus voltage is in this range?  If not, what will happen? will the CAN controller receive any wrong data from ISO1050? if yes, what is the difference between Bus Fault protection voltage range(-27~40V) and working insulation voltage range?

4) is that safe to use ISO1050 in a 48V system?

Kevin

  • Hi Kevin,
    1) VCANH/VCANL w.r.t. GND2 being between -12V to 12V is the recommended operating region. The device will work properly.
    2) When VCANH/VCANL w.r.t. GND2 is between -27V to 40V, You are right the device will not get damaged with the but the device might not work properly. CAN controller will get wrong data.
    3) In simple terms , Working insulation voltage is the voltage difference between GND1 and GND2 for which there Isolator is rated. This is not CANH/CANL to GND2 as you have interpreted.
    4) You can operate the ISO1050 in 48V system as along as you are which the Recommended operating conditions. You will need to step down the 48V to 3-5.5V and then give 48V to the VCC2-GND2. You should also ensure that even during fault conditions the Absloute max ratings are not violated.
    Regards,
    Sarangan Valavan
  • Hi SaranganValavan

    I am a newbie for CAN bus interface. Can you please clarify the below question ?

    Planning to use ISO1050 tranceiver..

    Even I have similar requirement for CAN transceiver to operate between 5 to 24 V CAN bus..Looking for protection & functionally working till +/-24V on Datalines as well.

    I will step down the voltage to 5V and provide it for VCC2. So what will be the voltage level at CANH & CANL ? Since the bus voltage is 24V, If other master on the bus drives the datalines at 24 V, Will it not damage the IC ?


    Bottom Line of the whole question is, Will the ISO1050 work properly for 5 to 24 Volt CAN bus when i connect VCC2=5V & VCC1=3.3V ?

    Thanks
    Pandiyan