When evaluating the TPS650861 device with the EVM, BOOSTXL-TPS650861, or a custom board it is important to first program the device using the OTP generator tool, which can be found on the product page on TI.com and linked below in this FAQ. Even if you do not wish to burn the settings into the one time programable (OTP) memory setting all registers according to the OTP generator tool is required for the device to work as expected.
This initial programming step is necessary because there are registers not shown in the datasheet that are set by the OTP generator tool. Instructions on using the OTP generator tool can be found in section 4 of the TPS650861 Non-Volatile Memory Programming Guide linked below.
Relevant document links: