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.