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Very low voltage drop transistor

  1. Jul 6, 2004 #1

    Cliff_J

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    I'd like to construct a fast-reacting current overload protection device. And rather than use a FET as a short to blow a fuse I'd rather just use a semiconductor in series that I can open on overload. This is similar in operation to some "intelligent circuit breakers" based on a Intra Technologies' MOSFET switch.

    Anyone know of any common (cheap) off-the-shelf FETs that with really low voltage drops? Thanks in advance.

    Cliff
     
  2. jcsd
  3. Jul 6, 2004 #2

    chroot

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    I think you mean FETs with really low on resistance. You should be able to do parametric searches at both the manufacturers' websites and on distributor websites.

    - Warren
     
  4. Jul 6, 2004 #3

    Gokul43201

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    ...like analog.com and digikey.com
     
  5. Jul 25, 2004 #4
    I'm not sure that this is the right way to solve the problem. If I were you, I'd go to the library and get a book on ESD protection in ICs. As a matter of fact, when I worked as an IC design engineer, we had a circuit like this in our intellectual properties library. Essentially, there was a resistor across the gate and drain of an n-type MOSFET. When a sudden current surge rushed across this resistor, the channel activated... in other words the drain was shorted to the source and most of the current went straight to ground without damaging the circuit.

    Individually-packaged, ordinary MOSFETs are almost impossible to come by... although I think you individually access the FETs of 500 series inverter. Most individually-packaged FETs are either power devices or RF devices. If you want circuit protection, then you're looking at power devices. If you want to reduce the channel (or source-to-drain) resistance, then I would just suggest tying several FETs in parallel.

    QuantumCowboy
     
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