Active production — no end-of-life risk for this BOM line
No last-time-buy window to watch, no forced redesign on the horizon. For a production BOM that already qualifies this 100-WLCSP variant, the supply outlook is stable.
80 MHz Cortex-M4 with 1 MB Flash — what the memory and speed mean for fit
That Flash density supports a full RTOS, a TCP/IP stack, and a moderate application image with room for field-upgrade staging. The 320 KB SRAM covers double-buffered graphics frames or a large audio buffer without external memory. The Cortex-M4 includes a single-precision FPU and DSP instructions, so sensor fusion or motor-control loops run in firmware rather than needing a separate coprocessor.
Peripheral set and connectivity — what is on-chip
An integrated LCD controller drives segment displays directly. Brown-out detect and a watchdog timer are built in, reducing external supervisory IC count.
100-WLCSP package — board-level considerations
This part comes in a 100-ball WLCSP (4.62 x 4.14 mm body). The fine-pitch wafer-level package saves board area but requires a controlled SMT process — the solder mask and stencil aperture need to match the 0.4 mm ball pitch. The 83 I/O count in this footprint gives good routing density for a mixed-signal design.
Supply voltage and power profile
The STM32L4 series is ST's ultra-low-power line; the active current at 80 MHz is typically under 100 µA/MHz in run mode, and stop-mode draw drops to a few microamps. For battery-powered or energy-harvested designs, this part is sized to extend run time.