according to the data sheet it looks to be possible to do a full shut down (off) (without controlling the PWR_EN) by sending a SEQDWN command to the password protected SEQ6 register.
In my case it is not happening even though I know I am writing to the register correctly. I tried to set the OFF bit in the STATUS register also. Nothing works. What is the proper commands to trigger a full shut down without controlling the PWR_EN pin?