Peripheral set and connectivity — what the 65 I/O give you
The STM32L476MEY6TR: 65 I/O lines, brown-out detect/reset, DMA, LCD controller, PWM, WDT. Connectivity includes CANbus, I²C, IrDA, LINbus, MMC/SD, QSPI, SAI, SPI, SWPMI, UART/USART, USB OTG. Two 12-bit DACs and sixteen 12-bit ADC channels. Internal oscillator.
Package and mounting — 81-UFBGA / WLCSP
The STM32L476MEY6TR is offered in an 81-ball Ultra-Fine-Pitch BGA (UFBGA) or Wafer-Level Chip-Scale Package (WLCSP). Both are surface-mount only and require controlled reflow profiles. The fine pitch and small ball diameter mean the PCB layout must follow the manufacturer's recommended land pattern and solder-mask opening closely. Moisture sensitivity level (MSL) is not stated in this listing, but standard practice for this package class is MSL 3 — bake before reflow if the sealed bag has been open beyond the floor-life window.
The base product number is STM32L476, and the STM32L4 family has broad second-source and cross-compatible siblings within the series — pin-compatible across density and feature variants.