64 MHz Cortex-M0+ in a 4x4 mm QFN — what it fits
The STM32G071GBU3: The 28-UFQFPN package (4x4 mm) keeps the board footprint small, and the 26 I/O lines plus a 12-channel 12-bit ADC and two 12-bit DACs cover sensor interfacing and control loops in a compact design.
This is a 28-lead QFN with an exposed pad underneath. The 4x4 mm body has low thermal mass, so it reflows fast — preheat the board to 150°C, then hit the package with hot air at 320°C for about 20 seconds. The pad is small enough that solder bridging between the perimeter leads is unlikely if your stencil aperture is right. MSL 3 out of the bag — bake at 125°C for 24 hours if the moisture barrier bag has been open longer than the floor-life window.
ST lists the STM32G071GBU3 as Active.