The PMIC chip has 4 terminations. The sum of the pins in this unit is 4. On the chip, there are pins for the 4 axis. This device has a regulator type called FIXED POSITIVE SINGLE OUTPUT LDO REGULATOR, which means it operates on a DC voltage.
LP3991TL-3.0 Features
LP3991TL-3.0 Applications
There are a lot of Texas Instruments LP3991TL-3.0 Linear Voltage Regulators applications.