There is no provision to disable DC-DC. Not connecting the DC-DC components to IC pins may result in misbehaving/non-working of the IC.
MAX16826
Production
The MAX16826 high-brightness LED (HB LED) driver is designed for backlighting automotive LCD displays and other display applications such as industrial...
Datasheet
MAX16826 on Analog.com
There is no provision to disable DC-DC. Not connecting the DC-DC components to IC pins may result in misbehaving/non-working of the IC.