PTC fuse Voltage rating

Discussion in 'General Electronics Chat' started by cages, May 23, 2011.

  1. cages

    Thread Starter New Member

    Jul 3, 2010
    19
    0
    I am working on making changes to an electronics design. The circuit board is powered by a 24V battery.
    There is a PTC resetable fuse on the boards power input, the data sheet for the part indicates that the maximum voltage is 15Vdc. I would assume that in a fault condition the whole 24V will be accross the PTC.

    Is there something I am missing about the Maximum Voltage rating of PTC resetable fuses that would make the part suitable?
    This is the first time I am using a PTC device in a design.
    The part is:SMD250F-2 (link to specification below)
    http://www.tycoelectronics.com/catalog/pn/en/RF0313-000?RQPN=SMD250F-2

    Thanks
     
  2. cages

    Thread Starter New Member

    Jul 3, 2010
    19
    0
    I found a link on the Tyco electronics website that answers my question-

    http://www.tycoelectronics.com/catalog/bin/TE.Connect?C=22878&M=HELP&BML=&PID=487412&N=29409&RQS=C~1^M~BYPN^TCPN~RF0313-000^RQPN~SMD250F-2

    "Vmax Operating-
    The maximum voltage across a PolySwitch device under a typical fault condition. In many circuits, this is the voltage of the power source in the circuit. It may be possible to use a PolySwitch device at a higher voltage, but each such use must be individually qualified."

    The design I am working on might be fine (has been qualified) but I think it might be worth using a PTC fuse
    with a higher Vmax (>24V).

    Thanks
     
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