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TPS746: 1.2Vout Dropout voltage vs Iout

daisuke kawasaki
Expert 4545 points

Part Number: TPS746

Hi expert,

My customer is concern about the dropout since the condition may be close to the marginal as below.

But TPS746 datasheet is not yet showing the table of dropout voltage vs Iout due to preview stage.  

  • Condition : Vin 1.8V -> Vout 1.2V, Iout = ~0.7A

Customer is picking up this device due to its small package.

Can you share the relative data if available?

Thank you and best regards,

Daisuke KAWASAKI

  • 0
    TI__Guru 55940 points

    Hi Daisuke,

    Dropout is linear with regards to output current.  As output current decreases, the maximum dropout (or minimum headroom Vin - Vout) required for regulation also decreases.

    At your conditions you have 600 mV headroom.  This is enough headroom to fulfill our maximum dropout specification at 1 A; therefore, you will have enough headroom for 0.7 A as well.  While the limits may change slightly before this LDO is fully released, we do not expect them to move very much.

    If we calculate the expected maximum dropout for 700 mA we find that there is ample margin:

    Vdo700mA / 700 mA = Vdo1A / 1 A

    Vdo700mA / 700 mA = 580 mV / 1 A

    Vdo700mA = 406 mV

    Very Respectfully,

    Ryan