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Dropout voltage of LM350K STEEL/NOPB @ 3A out out current

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Replies: 6

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Part Number: LM350K STEEL/NOPB (unable to select)

Dropout voltage of LM350K STEEL/NOPB @ 3A output current.

whats the minimum voltage i can give to get 5.0 V @ 3 A

or

other device with 5 volt adjustable output @ 3A, TO-3 STEEL package.
least possible dropout voltage.

  • Hello Madiwalesh,

    The LM350 Minimum Operating Vin to ensure 3A output = Vout+3V = 5.0V+3.0V = 8.0V

    That will cause 6W (3A x 3V) to be dissipated in the K (TO-3 / NDS) package. A heat sink will be needed.

    I do suggest that you consider a Buck SMPS as it will give superior efficiency (less heat).

    If a linear regulator is required, here are some options with lower Vin to Vout requirements:

    LM1084 - 5A Low Dropout Positive Regulators

    www.ti.com/.../LM1084

    LM1085 - 3A Low Dropout Positive Regulators

    www.ti.com/.../LM1085

    LP3856 - 3A Fast Ultra Low Dropout Linear Regulator

    www.ti.com/.../LP3856

    LP3873 - 3A Fast Ultra Low Dropout Linear Regulator

    www.ti.com/.../LP3873

  • In reply to Donald Jones:

    Thanks for the reply   

    Thanks for the suggestion. SUGGESTION you have made is the cause this question rose to us. The constraint  to us is we already have a board made with LM350K STEEL/NOPB  (TO-3 STEEL) Metal Can Package, with input voltage 9.0 V. We are in plan to insert a PCB with SMPS (BUCK) & reduce 9.0 v to minimum possible, before supplying 9.0 V to LM350K STEEL/NOPB. since the Board already present cannot be changed can i get any device with lesser drop out but (TO-3 STEEL) Metal Can Package

    can i get a graph of Dropout voltage or (minimum required) vs current driven for LM350K STEEL/NOPB.??



  • In reply to MADIWALESH PATTAR:

    " ... can i get a graph of Dropout voltage ..."

    Yes, from the LM350 datasheet ...

  • In reply to Donald Jones:

    can i get any device with lesser drop out but (TO-3 STEEL) Metal Can Package

  • In reply to MADIWALESH PATTAR:

    List of every TI regulator in the TO-3 package that can deliver at least 3A:

    Part Number

    Description

    Minimum Vin-Vout

    LM138

    LM138 5-Amp Adjustable Regulator

    3.0 V

    LM338

    LM338 5-Amp Adjustable Regulator

    3.0 V

    LM323-N

    LM323 3-Amp, 5-Volt Positive Regulator

    2.5 V

    LM350-N

    LM350 3-Amp Adjustable Regulator

    3.0 V

    Looks like the LM323 is just a bit lower.

  • In reply to Donald Jones:

    Thank you. will have a look into it.

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