The STM32F401xD from STMicroelectronics is a Space Qualified Microcontroller with Clock Rate 32 kHz to 26 MHz, Operating Frequency 84 MHz, Internal RAM Memory SRAM : 96 kB, Flash Memory 384 kB, Supply Voltage 1.7 to 3.6 V. Tags: Surface Mount. More details for STM32F401xD can be seen below.