84 MHz Cortex-M4 for control-loop throughput
The STM32F401RBT6TR is an STM32F4-series ARM Cortex-M4 MCU clocked at 84 MHz, delivering the DSP instruction set and single-cycle MAC that a Cortex-M3 lacks. For a motor-drive current loop or a sensor-fusion algorithm running at a few kilohertz, the 84 MHz ceiling leaves margin above the 32 MHz of the STM32L1 sibling without pushing into the higher-power STM32F405 range. 128 KB of on-chip flash and 64 KB of SRAM (64K x 8) give the firmware budget for a moderate application stack — a FreeRTOS kernel with a USB CDC class driver and a few peripheral handlers fits within 80 KB of flash, leaving the rest for application code. The 64 KB SRAM handles the runtime heap and DMA buffers without external memory.
Package and board-fit: 64-LQFP 10x10 mm
Housed in a 64-LQFP package with a 10x10 mm body and 0.5 mm pitch, the STM32F401RBT6TR requires a 4-layer PCB for reliable fan-out of the inner rows. The 50 I/O lines include the peripheral multiplexing for USB OTG, SDIO, and multiple SPI/I²C/UART interfaces — enough for a sensor hub or an HMI panel controller without a port expander. The 1.7 V floor is low enough to operate on a nearly-depleted battery without a boost converter, though the flash access time may require wait-states at the lower end of the voltage range.
Industrial temperature grade and peripheral set
The on-chip peripherals include DMA channels for memory-to-peripheral transfers without core intervention, PWM timers for motor or LED drive, and a watchdog timer for fail-safe reset. The 12-bit ADC offers 16 multiplexed channels — enough to sample multiple analog sensor inputs (thermistors, current shunts, potentiometers) in a round-robin sequence without an external mux.
Active lifecycle and compliance
It is ROHS3 compliant, meeting the EU RoHS directive without exempted substances. The tape-and-reel packaging (TR suffix) is the standard reel quantity for automated pick-and-place assembly; cut-tape (CT) options are also listed for prototype runs.