Internal oscillator and POR trim the external BOM count.
That split lets you power the core from a 1.8 V regulator and interface directly with 3.3 V peripherals without level shifters — a common pattern in battery-operated or single-coin-cell designs where the core voltage is kept low for efficiency. The 1.65 V minimum on both domains also means the MCU can operate from a near-depleted lithium cell, which extends run time in portable equipment.
100-UFBGA (7x7) — footprint and rework considerations
Housed in a 100-ball Ultra Fine-pitch BGA measuring 7 mm on a side, this package saves board area compared to an LQFP-100 but demands careful PCB layout and rework capability. The ball pitch requires via-in-pad or microvia routing for the inner rows.
The 85°C ceiling is typical for commercial-industrial equipment; if the design sees sustained junction temperatures above that, a higher-temperature variant from the STM32F0 family would be needed.
For long-term supply assurance, the STM32F0 series has broad second-source availability through independent distribution, and the base product number STM32F078 allows cross-referencing to other density and package options within the family.