What are the considerations when using MOSFETs in parallel?

When MOSFETs are used in parallel, a current imbalance is caused during switching transitions by a mismatch between each device characteristics and between circuit wiring layout of each MOSFETs.
This current imbalance could increase power losses and lead to destruction of a MOSFET. Exercise care concerning current imbalance.

Preventing this current imbalance.

  1. Make a symmetrical layout of circuit wiring.
  2. Assemble MOSFETs to one heatsink so that the thermal dissipation condition is the same for each MOSFET.
  3. Use an external gate resistor for each MOSFET.
  4. Secure a large current margin, considering current imbalance.
    Based on consideration of the above items, please confirm that your circuit does not have a problem.

For using MOSFETs in parallel, please refer to “MOSFET Paralleling (Parasitic Oscillation between Parallel Power MOSFETs): Power MOSFET Application Notes.”