This application note describes the usage of the DC-DC Switching Mode Power Supply (SMPS) converter for the MKW39A/38A/37A/38Z/37Z families. This document covers operating voltages, types of circuit operation, hardware design guidelines, software configuration, and power capabilities. It's a complementary document from the AN5025. The DC-DC converter for MKW3x is a dual output converter that supports two operating modes: Bypass and Buck. In Bypass mode, the DC-DC converter is disabled and the supply pins of the microcontroller must be supplied externally. In Buck mode, the DC-DC converter is enabled and requires a DC supply in the range of 1.8 V to 4.2 V (during startup the minimum required is 2.1 V).

This document provides information on distance measurements depending of the Bluetooth LE data rate (1Mbps, 2Mbps, LR S=2 & LR S=8). The FRDM-KW38 boards are used to perform the measurements. Results are similar on KW37 and KW39.  

In addition of the Design Guideline, PCB hardware package find here the design in check list to build sucessfully your own PCB