84 MHz Cortex-M4 in a wafer-level chip-scale package
The STM32F401CBY6TT is an STMicroelectronics STM32F4-series MCU built around an ARM Cortex-M4 core clocked at 84 MHz. The 49-ball WLCSP (0.4 mm pitch) saves board area for wearables, sensor nodes, and compact control modules, but demands controlled assembly — the wafer-level package is moisture-sensitive and requires a reflow profile matched to the 0.4 mm ball pitch.
Peripheral set and I/O budget
The 10-channel 12-bit ADC (A/D 10x12b) covers analog inputs for battery monitoring, knob position, or ambient-light sensing. On-chip peripherals include DMA, PWM timers, a watchdog, brown-out reset, and POR — enough to run a modest RTOS or bare-metal control loop without external supervisory ICs.
It is not rated for under-hood or downhole environments — those call for the -40 to 125 °C extended-range siblings in the STM32F4 family. The internal oscillator trims the BOM by one crystal, though an external clock source improves timing accuracy for USB or CAN operation.
STMicroelectronics lists the STM32F401CBY6TT as Active. No last-time-buy or phase-out notice is in effect. For dual-sourcing resilience, the STM32F401 series includes pin-compatible density variants (e.g., 256 KB Flash / 64 KB RAM) in the same WLCSP-49 footprint — a BOM-level swap without board respin.