The Holtek HT66F0025 is an 8-bit MCU with the HT8 core, featuring a 12-bit ADC with selectable bandgap reference for stable, accurate conversion in varying voltage and temperature conditions. Designed for battery-powered and AC supply applications, it offers strong ESD/EFT protection and flexible clocking with both an 8 MHz high-speed RC oscillator (±2% accuracy) and a 32 kHz low-frequency RC oscillator.