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replacement for the RC1117S33T — Parallax Forums

replacement for the RC1117S33T

Matt BattleMatt Battle Posts: 172
edited 2006-12-12 01:17 in General Discussion
Hey all,

I know this has nothing to do with parallax products but i know there is alot of you electronics folks out there. I am looking for a replacement for the obsolete Fairchild Semiconductor's RC1117S33T-ND which is a Voltage Regulator for 3.3V at 1A in a SOT-223 package. Thanks

Regards,
Matthew

Post Edited (Matt Battle) : 12/6/2006 10:03:06 PM GMT

Comments

  • Paul BakerPaul Baker Posts: 6,351
    edited 2006-12-07 03:04
    ADP3338AKCZ-3.3RL7
    LM3940IMP-3.3
    LX8117A-33CST

    Ive only matched those specs you provided, you'll need to check the datasheets to see if any other needed parameters match.

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    Paul Baker
    Propeller Applications Engineer

    Parallax, Inc.
  • Matt BattleMatt Battle Posts: 172
    edited 2006-12-07 03:55
    Hey Paul,

    Thanks for your help. It looks like the LX8117A-33CST-ND is going to be the one I will be using in place of the RC1117S33T-ND. The other two parts have come up as obsolete.

    Regards,
    Matthew
  • Matt BattleMatt Battle Posts: 172
    edited 2006-12-11 21:02
    Hello everybody,

    I know that voltage regulators run hot but is there anything I can do to cool down a SOT-223 package regulator? Does anybody recommend something else that is more efficient then that? I was told to look into switching regulators. Would that be a beneficial and cost effective switch ?

    Thanks everybody,
    Matt
  • PJAllenPJAllen Banned Posts: 5,065
    edited 2006-12-11 22:54
    The best (only?) thing to do here, linear-wise,·would be to decrease the input voltage (that is, decrease the input to output differential.)
  • Matt BattleMatt Battle Posts: 172
    edited 2006-12-11 23:35
    Yea, that is what I was thinking but it would up to the end-user to remember and follow the warning about using a power supply above 6v.
  • PJAllenPJAllen Banned Posts: 5,065
    edited 2006-12-11 23:55
    If you're making a printed-circuit board, you could leave (exposed) copper beneath the regulator IC, the ground plane in that area would not get solder-masked, as an albeit imperfect heatsink.
  • Paul BakerPaul Baker Posts: 6,351
    edited 2006-12-11 23:56
    Switching regulator can be used, they are more efficient, and produce less heat. But they can be tempermental in thier use (component placement, minimum current draw and other things) and require more external components (almost always an inductor and frequently a mosfet). You would need a buck type regulator for your application.

    ▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
    Paul Baker
    Propeller Applications Engineer

    Parallax, Inc.
  • Matt BattleMatt Battle Posts: 172
    edited 2006-12-12 01:17
    Paul Baker (Parallax) said...
    Switching regulator can be used, they are more efficient, and produce less heat. But they can be tempermental in thier use (component placement, minimum current draw and other things) and require more external components (almost always an inductor and frequently a mosfet). You would need a buck type regulator for your application.

    Thanks Paul for the input. Room is limited on the board that I am using so I am stuck with the SOT-223 package I am using. I will be designing a new board the next few weeks and I will be using a voltage regulator in a TO-220 with a heat sink to help distribute the heat.
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