DRV8411: Current rating question verses DRV8833

The DRV8411 data states that it is a 4 Amp driver, which is quite a bit more than the DRV8833 which is rated as 1.5A RMS or 2A peak; however, both the FET resistance and the thermal resistance of the DRV8411 part appear to be higher than those of the DRV8833... normally this would mean that the DRV8411 would be able to drive less current. I was wondering if there was more information on this.