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TPS2553-Q1: Confirmation on the maximum voltage which can be applied at the output pin of this device

Part Number: TPS2553-Q1
Other Parts Discussed in Thread: TPS2553

HI,

I have a query on the Maximum output voltage which can be safely applied to this device:

In the datasheet its mentioned as below:

According to this The maximum voltage which can be applied safely to device is 7V? is it correct?

In our automotive application, The output of this device goes out of our board through a connector. There are chances that this output may be shorted to Battery ( in this case about 32V) or shorted to Ground. can the device protect itself against these conditions without damaging?

Also, There is Reverse voltage protection feature in built in this device as shown below:

As per my understanding:

At the instant, the output voltage goes above the input voltage by about 190 mV for 7 ms, The device raises the fault flag.

My question is:

Does this device shut itself off for any voltages above 5.19V?  Will this reverse voltage protection work at 12V,24V,36V Applied at the output pin?

Please resolve my queries.

Thanks

Kunmit

  • Hi, Kunmit,

    I can't see the picture you attached. But according to your description, please see my reply below:
    1. [Q]can the device protect itself against these conditions without damaging?
    [A]This part can protect itself against short to ground without damaging, please refer figure20 in datasheet. But it can't be used in short to battery case. This part maximum voltage on OUT pin is 7V, we don't recommend apply a voltage over 7V on OUT pin. In your case, battery voltage is 32V, TPS2553-Q1 will be damaged.
    2. [Q]Does this device shut itself off for any voltages above 5.19V? Will this reverse voltage protection work at 12V,24V,36V Applied at the output pin?
    [A]Only when Vin=5V, the device will shut itself off when a voltage above 5.19V is applied on OUT pin, because the reverse voltage comparator trip point is VOUT-Vin , not Vout. Please refer 6.5 electrical characteristics. And this part can't be used at 12V,24V,36V, these voltages are out of recommended operation conditions.
  • Hi Bob,

    Thanks for your reply.

    with respect to your answer to my 2nd query, I have the following doubt:

    As you explained if the Input voltage to the device is 5V, then the device will shut itself off in case the voltage at the OUT pin is > 5.19V because of the reverse voltage comparator trip point. My next question is, if the Vin=5V, and if we apply 32V at the output, does the device still shut off?( because the output voltage is>5.19V) or will the device be damaged?.

    Thanks for your support.

    Regards

    Kunmit

  • Hi, Kunmit,

    This part is a low-voltage part, the max voltage on VOUT is 7V. If you apply 32V at output, the part will be damaged no matter how much Vin is, even though this part is disable or power off or under reverse voltage protection. The MOS inside can't sustain so much voltage.

    Regards,
    Bob
  • Hi Bob,

    Thanks for your reply.

    Since it is clear that voltage >7V cannot be sustained at the OUT pin of the Mosfet, I Guess in Our application we need to protect the pin.

    In our application, there are chances of short to Battery ( short to 32V) for this OUT pin. In this case, I feel we can use this IC OUT pin provided we have to protect it from short to battery.

    For this we can use a  Zener Diode( possibly a 5.1V) at the OUT pin before giving to external world, which can limit the voltage in case of short to battery condition. Please refer to attached image below for rough connections. Is it OK? Will the TPS2553 sustain the voltage at the OUT pin this case?

    Thank

    Kunmit

  • Hi, Kunmit,

    I got what you mean. I am not sure if the Zener Diode response time is fast enough to clamp VOUT from 32V to 5V. So I suggest you monitor VOUT voltage when you short VOUT to battery. If the voltage peak is smaller than 7V, it's okay to use zener diode. Otherwise not.

    Besides, FYI, some customers use TVS for short battery protection not zener diode, cuz TVS has faster response time.

    Regards,
    Bob
  • Thanks Bob for your reply.