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SN6505B: what's the Absolute Maximum Ratings Peak output switch current @ 90 degree C?

Part Number: SN6505B

Hi 

in SN6505B datasheet, the Absolute Maximum Ratings Peak output switch current @ 25 degree C is 2.4A.

Recommended Operating Conditions Output switch current - Primary side is 1A.

now customer's application input is 5V, they can see 1.2A peak inrush current at SN6505B startup, and in some projects, the output capacitor is even larger, so the peak current will be 1.8A. inrush current waveform is as below.

customer want to know what's the Absolute Maximum Ratings Peak output switch current @ 90 degree C of SN6505B?

can 1.8A inrush current be support by SN6505B at 90 degree C?

  • Hi Max,

    All the values listed as typical (and not as min or max) in datasheet are the values measured at TA = 25C. 2.4A of peak output switch current specified in absolute maximum ratings of SN6505x datasheet is the maximum (and not typical) the device can support across temperature. Hence this current spec is valid for upto TA = 125C.

    Please note that the absolute maximum ratings provided in datasheet are not be operated at regularly and are only meant as limits for undesired fault conditions. Inrush current is going to happen every time there is system power-up and is considered to be part of regular device operation. Hence the recommended current limit spec of 1A from datasheet would be applicable even for inrush current.

    Considering that the 1.8A of inrush current is only happening for about 10ms, it may not affect device's lifetime but since this is exceeding recommended operating conditions we would not be able to guarantee device's lifetime under such operation.

    Let me know if you have any other questions, thanks.


    Regards,
    Koteshwar Rao
  • In reply to Koteshwar Rao:

    Hi Rao,

    becuase SN6505B has a fixed soft start, if customer needs to reduce inrush current to below 1A, how does customer do?

    thanks.

  • In reply to Max Han:

    Hi Max,

    I understand your concern. With the suggested decoupling capacitors, we do not expect to see much of inrush current.
    Do you know what is the input and output decoupling capacitors is customer using? Alternatively, you can also send me customer schematic over email if possible. Thanks.


    Regards,
    Koteshwar Rao