The output devices in a power module are usually not switched on or off at the same time. After the bottom switch has been opened, closing the top switch, due to the associated high dV/dt, can cause a current to flow through the parasitic drain-gate capacitance of the bottom switch and through the gate resistor, into the gate driver. This current is called Miller current and it can cause the gate voltage of the bottom switch to rise above the gate's threshold voltage, closing the switch. This is a very unfavorable situation as the resulting shoot-through current will destroy the half-bridge.

The solution is to implement an active device (FET) to clamp the gate of the bottom switch to ground when the switch is supposed to be open, hence the name 'active Miller clamp'. The clamp is on as soon as the bottom switch's gate voltage drops below a certain voltage when it is switched off and releases when the gate driver turns the bottom switch back on again.

Both SA110 and SA310 are equipped with active Miller clamping.