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TIOS101: TIOS101 operating voltage

bbrienzo
Prodigy 90 points
Part Number: TIOS101

I'd like to use the TIOS101 in a 24V-48V application.

The datasheet shows an absolute max rating on VCC and OUT of 55V, but a recommended max of only 36V.  What is the reason for the wide difference in absolute vs recommended?  Is it because of the internal LDO dissipating too much heat at >36V?  And if so, does that mean I can use the version without the internal LDO safely and continuously at 48V?  Or are there other components that also don't like >36V?

Ben

  • 0
    TI__Mastermind 19360 points

    Hi Ben,

    Thank you for your question and interest in this device.

    First, I will point out that last year the absolute max voltage was increased from 55V to 60V.  We did some additional testing and were able to increase this limit.  The current version of the datasheet has this value and if you have an older version of the datasheet, I wanted to point out there is a newer one.  Sometimes your browser will use a cached version instead of displaying the new one, so if you can't view the updated one, you may need to clean out your browser's cache to get the new one.

    But to the source of your question, the device was designed, characterized, and guaranteed for operation with a maximum supply voltage of 36V.  The device will not break if a higher voltage less than the absolute maximum is used, but the parameters cannot be guaranteed.  And yes, one of the predominant factors is the excess heating that results from using a higher voltage.  The device has a thermal shutdown feature to protect itself and I would not recommend disabling the current limit monitoring feature that will disable the output in an event of an over current condition that could cause damage to the device if it overheats.  With the larger voltage, more current and heat will result from the residual voltage drop through the reverse blocking diodes and transistors.

    One of the primary reasons for the large absolute max voltage levels compared with the maximum recommended operating voltage is the need to protect the device from damage that results in the overshoot and kickback voltages generated from various inductive and capacitive loads.  For example, if there was a large inductor or Relay connected to the OUT pin.  Even if the supply voltage is only a typical 24V, the kickback voltage when the inductor is demagnetizing will be very large and could cause damage to the device.  The TIOS101 does have some ability to clamp this voltage to a tolerable range and prevent damage, but generally speaking, these types of applications is why the device was designed to survive some larger voltages, even though this is not an endorsement to operate at a static higher voltage condition.

    I hope this helps answer your question.

    Regards,

    Jonathan