The preregulated 1.85-V mode of operation applies an external regulated 1.85 V directly at pins 10, 25, 33, 36, 37, 39, 44, 48, and 54 of the device. The VBAT and the VIO are also connected to the 1.85-V supply. This mode provides the lowest BOM count version in which inductors used for PA DC/DC and ANA1 DC/DC (2.2 and 1 µH) and a capacitor (22 µF) can be avoided.
In the preregulated 1.85-V mode, the regulator providing the 1.85 V must have the following characteristics:
The regulator must be placed as close as possible to the device so that the IR drop to the device is very low.