C8051F388-B MCUs Silicon Labs C8051F388-B MCUs are fully integrated mixed-signal System-on-a-Chip MCUs. These MCUs feature high-speed 8051µC core, 4352 or 2304 bytes RAM, and 64kB or 32kB flash. The operating supply voltage ranges from 2.7V to 5.25V and operating temperature ranges from -40°C to +85°C. Silicon Labs C8051F388-B MCUs are available in 48-pin TQFP, 32-pin LQFP, and 32-pin QFN packages.