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BS2p 15uF 16V cap availability — Parallax Forums

BS2p 15uF 16V cap availability

FlyingFishFingerFlyingFishFinger Posts: 461
edited 2007-11-23 19:49 in General Discussion
Hi-
my understanding is that this component is a 15uF 16V tantalum cap. I'm planning on rebuilding a Stamp module on my own board, but I can't seem to find this part. Digikey, Mouser and Avnet all have it, but no one has it in stock and the minimum order quantities are 500 or 2000, depending on where you look.
Is there anywhere else I can find 5-10 of these capacitors?
Thanks

Raf

▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
You've got to play the game.
You can't win.
You can't break even, except on a very cold day.
It doesn't get that cold.
~Laws of Thermodynamics~

Comments

  • LilDiLilDi Posts: 229
    edited 2007-11-21 18:55
    http://www.jameco.com
  • RDL2004RDL2004 Posts: 2,554
    edited 2007-11-21 18:58
    Mouser search - capacitors tantalum 15uf 16v in stock

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    - Rick
  • Chris SavageChris Savage Parallax Engineering Posts: 14,406
    edited 2007-11-21 21:17
    It might also help to pick a more common value such as 16uF @ 16V. Take care.

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    Chris Savage
    Parallax Tech Support
  • FlyingFishFingerFlyingFishFinger Posts: 461
    edited 2007-11-21 21:47
    How close (or not) must I be to the given value of 15uF 16V?
    Thanks

    Raf

    ▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
    You've got to play the game.
    You can't win.
    You can't break even, except on a very cold day.
    It doesn't get that cold.
    ~Laws of Thermodynamics~
  • RDL2004RDL2004 Posts: 2,554
    edited 2007-11-22 12:51
    Are you trying to re-create the Stamp in surface mount? The schematic for the 2P-24 doesn't specify tantalum. It looks like it's just a filter cap on the regulator output. Low ESR may be all that's important (low drop-out regulators are known for this), a larger value and/or higher working voltage may be fine.

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    - Rick
  • FlyingFishFingerFlyingFishFinger Posts: 461
    edited 2007-11-22 18:05
    Yes and no. I have a project I'm rebuilding surface mount and I would like to integrate the Stamp. Low ESR? Ok, thanks[noparse]:)[/noparse]

    Raf

    ▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
    You've got to play the game.
    You can't win.
    You can't break even, except on a very cold day.
    It doesn't get that cold.
    ~Laws of Thermodynamics~
  • RDL2004RDL2004 Posts: 2,554
    edited 2007-11-23 11:29
    Assuming you use the same regulator as the BS2P-24, attached is the data sheet for the LT1121 and here are the relevant parts:

    Other features of the LT1121/LT1121-3.3/LT1121-5 include
    the ability to operate with very small output capacitors. They
    are stable with only 0.33μF on the output while most older
    devices require between 1μF and 100μF for stability. Small
    ceramic capacitors can be used, enhancing manufacturability.

    and

    The LT1121 is designed to be stable with a wide range of
    output capacitors. The minimum recommended value is 1μF
    with an ESR of 3Ω or less. For applications where space
    is very limited, capacitors as low as 0.33μF can be used if
    combined with a small series resistor. Assuming that the
    ESR of the capacitor is low (ceramic) the suggested series
    resistor is shown in Table 6. The LT1121 is a micropower
    device and output transient response will be a function of
    output capacitance. See the Transient Response curves
    in the Typical Performance Characteristics. Larger values
    of output capacitance will decrease the peak deviations
    and provide improved output transient response.

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    - Rick
    pdf
    pdf
    LT1121_datasheet.pdf
    175K
  • FlyingFishFingerFlyingFishFinger Posts: 461
    edited 2007-11-23 17:24
    Ah actually I had just downloaded that yesterday, but I haven't gotten around to reading it in full yet. Also, I'm not sure if I'm going to be using that reg or not, because I want it to power my entire board, not just the stamp relevant components. I'll be looking for something a little more high-powered.
    Thank you though

    Raf

    ▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
    You've got to play the game.
    You can't win.
    You can't break even, except on a very cold day.
    It doesn't get that cold.
    ~Laws of Thermodynamics~
  • Mike GreenMike Green Posts: 23,101
    edited 2007-11-23 17:35
    You'll have to figure out which regulator you're going to use before you can decide on the output capacitor value.

    Also, with a 5V or 3.3V output, you don't need a 16V capacitor. With a 5V output, anything from about 6V up should do.
  • FlyingFishFingerFlyingFishFinger Posts: 461
    edited 2007-11-23 19:00
    Thanks Mike, I'll keep that in mind.
    I feel stupid asking this, but the Stamp's regulator doesn't seem like a switcher...don't those normally need inductors? Is it linear?
    Thanks

    Raf

    ▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
    You've got to play the game.
    You can't win.
    You can't break even, except on a very cold day.
    It doesn't get that cold.
    ~Laws of Thermodynamics~
  • Mike GreenMike Green Posts: 23,101
    edited 2007-11-23 19:26
    The Stamp's regulator is linear. The amount of power involved is low and the complexity, cost, and space requirements for a switching regulator are too high to justify for the on-module regulator. If you're planning to draw higher currents (1/2 to 1A or more) or run with significant voltage drop (inputs above 7.5V), do seriously consider a switcher.
  • FlyingFishFingerFlyingFishFinger Posts: 461
    edited 2007-11-23 19:49
    I'm thinking that if I want to drive servos from the reg, I need a switcher. Can I feed the output from one directly into the Stamp?
    Raf

    ▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
    You've got to play the game.
    You can't win.
    You can't break even, except on a very cold day.
    It doesn't get that cold.
    ~Laws of Thermodynamics~
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