The STM32F303Cx from STMicroelectronics is a Space Qualified Microcontroller with Clock Rate 32 kHz to 32 MHz, Operating Frequency 72 MHz, Internal RAM Memory SRAM : 32 to 40 kB, Flash Memory 128 to 256 KB, Supply Voltage 2 to 3.6 V. Tags: Surface Mount. More details for STM32F303Cx can be seen below.