Parallel MOSFET

Discussion in 'General Electronics Chat' started by ojotoxy, May 22, 2009.

  1. ojotoxy

    Thread Starter Member

    Jan 6, 2009
    If I connect, say 3 or 4 MOSFETs in parallel, to increase current capability, spread heat, and reduce cost..
    They are connected in parallel, as in gate-gate, source-source, drain-drain.
    It should have 3 times the gate capacitance, but that shouldn't affect speed,
    3x the max current,
    1/3 the on state resistance.

    What happens to the transconductance?
    If it's used as a switch is there a potential problem if they don't turn on all at the same moment, even if only nS apart?

    Need help, thanks.
    Last edited: May 23, 2009
  2. mindmapper

    Active Member

    Aug 17, 2008
    3 times the gate capacitance, also means that the driver needs to be three times as powerful, othervise it would affect speed.

    If one is slightly slower/faster than the other wouldn't matter as long as they don't operate at very high frequency. If the switching loss is high, the slow/fast transistors will take more heat dissipation than the other.