64-TFBGA — rework and layout reality
This part comes in a 64-ball TFBGA (5x5 mm body) — fine-pitch, no exposed paddle. The 0.5 mm ball pitch means a 4-layer board with microvias is the practical minimum for routing all 51 I/O plus supply and ground. Under the hot-air station, pre-bake at 125°C for 24 hours if the moisture-barrier bag has been open past the floor life; MSL 3 is typical for this class. Will it survive rework? Yes, with a decent preheat and a rework nozzle sized to the body. The small thermal mass reflows cleanly.
Supply range and power budget
At 32 MHz the core draws in the low milliamps range; stop-mode current is typically under 2 µA with the RTC running.