Power ground for the sense resistor, R S , should be connected as close to the device as possible, and should be returned separately to the ground pins of the device. R S should be non-inductive, and the circuit board ground run should be as large as physically possible. Both current and voltage controlled. The A3958 incorporates a fixed-off time PWM circuit to regulate the current in the winding of the DC motor. Use external Schottky diodes in parallel with the internal DMOS body diodes.
Heat sinks are also a possibility.
However, Schottky diodes are typically the preferred solution. This page may not display correctly without a javascript-enabled browser.