Using the EPC21601, is it possible to drive the gates of a BLF189XRA (1500 Watt Power LDMOS) in a push pull manner. I need to drive the gates at 40MHz; this would probably be through a gate driver transformer and each gate needs approximately 1.5 W of power between -4 V and +11 V
Yes, a push-pull through a 1:1 gate drive transformer with CT primary and secondary is possible: Primary - Two EPC21601 driving a CT primary with the CT connected to 12V, Secondary - Use the CT and one of the outside winding to create a 6V push pull gate drive. It will double the drive current. Maybe have a Zener diode clamp to protect the gate on the -6 negative swing. You can think of the EPC21601 as a low side gate driver + medium power GaN FET with an Open drain output.