48 MHz is the sweet spot for a low-power 32-bit controller handling sensor fusion, USB data logging, or LIN-bus body control. It is not a high-throughput DSP core; the M0+ trades peak MIPS for lower active current and a smaller code footprint. For a design that needs USB host/device capability without a separate PHY, this part keeps the BOM count down.
Memory and peripheral budget
The 23 GPIO pins limit parallel I/O expansion.
NXP lists the MKL26Z128VFM4 as Active. The part is still in NXP's production portfolio.
HVQFN (5x5 mm) with wettable flanks. The wettable flank feature allows AOI verification of solder joints on the hidden QFN pads.