Memory ceiling and analog integration — what fits in 32 KB / 8 KB
The STM32F051R6T7TR: The 19-channel 12-bit ADC lets you sample multiple analog inputs without an external mux, and the single 12-bit DAC provides one analog output for setpoint generation or waveform synthesis. The internal oscillator saves the crystal BOM cost for applications that can tolerate ±1% accuracy over temperature.
The base product number is STM32F051, and the series is STM32F0. For dual-sourcing, the STM32L151CBU6A is a different architecture (Cortex-M3 at 32 MHz, 1.8 V supply, 85°C max) — not a pin-compatible second source, but a lower-power sibling if the project later needs USB and extended battery life.
The MCU is supplied in a 64-LQFP package with a 10x10 mm body, surface-mount. Supply voltage range is 2.0 V to 3.6 V, covering 3.3 V and 2.5 V rails. ROHS3 compliant.