High speed flash analog-to-digital converters are used in modern high-performance telecommunication systems. Furthermore, high effective resolution of such converter should be provided. The paper presents a design of a flash analog-to-digital converter with high effective number of bits. As an example, the 8-bit flash ADC in 180 nm CMOS has been implemented. Simulation confirms efficiency of proposed design. The effective resolution of presented design achieves 6.9 bits.