Memory map and peripheral fit
The 640 KB SRAM is unusually generous for this class — enough for dual display buffers or a large audio sample cache. The connectivity set includes CANbus for industrial fieldbus, USB OTG for host/device switching, and an EBI/EMI bus for glueless connection to external SRAM, NOR Flash, or LCD controllers.
This is a standard-production STM32L4R series device, widely stocked across the distribution channel. For dual-sourcing or supply resilience, note that the STM32L151CBU6A is a different series (STM32L1, Cortex-M3 at 32 MHz) and is not a pin-compatible or functional substitute — the L4R5's 120 MHz core, 1 MB Flash, and 640 KB SRAM are in a higher performance tier. No direct second-source alternate exists; the STM32L4R5 is a single-sourced ST part.