DRV8711: The phase current parameter of the motor is 4A but IFS is 4.5

Hi experts,

   Nice to e-meet you! This is GREE FAE Skylar. 

   There is a question from GREE about DRV8711.  The phase current parameter of their motor is 4A. But when they tested their board performance, if they want to run the maximum speed of the motor, IFS should be set 4.5. If the IFS is not set 4.5, the speed of motor will be much slower.

• The phase current parameter of their motor is 4A. Is this max value or RMS value?
• Could you pls help tell me if the IFS is set to 4.5, will it lead to damage the motor?

    Look forward to have your reply. Thanks. 

BR,

Skylar