TYPICAL SYSTEM OPERATION

The MSK4358 is designed to be used with a +270 volt high voltage bus, +15 volt low power bus, and +5 volt logic signals.

Proper derating should be applied when designing the MSK4358 into a system. High frequency layout techniques with ground

planes on a printed circuit board is the only method that should be used for circuit construction. This will prevent pulse jitter caused

by excessive noise pickup on the current sense signal or the error amp signal.

Ground planes for the low power circuitry and high power circuitry should be kept separate. The two sections of the hybrid are

completely isolated, and can float relative to each other without referencing one to the other. An RC filter will filter out the current

spikes and keep the detected noise for that circuit down to a minimum.

The logic signals coming from the typical motor controller IC are set up for driving N channel low side and P channel high side

switches directly, and are usually 15 volt levels. Provision should be made for getting 5 volt logic signals to the MSK4358 of the

correct assertion levels. Typically, the low side signals out of the controller are high active and the high side are low active.

Inverters are shown in the system schematic for the high side controller output.

PRELIMINARY Rev. B 11/01

5