The documentation is only valid for the LPC55xx and LPC55Sxx families. In power down mode, some of peripherals for LPC55xx are power off, which means that the peripherals lose it’s power in power-down mode, so it is required to reinitialize the peripherals after waking-up from power down mode. The DOC lists the peripherals which lose power in power down mode and are required to initialize, introduces the procedure to enter the power down mode, and the procedure to reinitialize the peripherals after waking-up from power down mode.
The doc is attached and power scheme is also attached.
