This paper describes a 10b 204MS/s analog-to-digital converter (ADC) employing a pipelined successive approximation register (SAR) architecture for low power consumption and small area. To improve the operation frequency, the pipelined SAR ADC consists of two channels with a proposed asynchronous timing technique. This technique increases the amplification time of a residue opamp. To reduce power and area, the opamp is shared between two channels. A reference buffer with a deglitch circuit reduces the glitch and settling time of reference voltages. The prototype ADC fabricated in a 65nm CMOS process shows a SNDR of 55.2dB and a SFDR of 63.5dB with a 2.4MHz input at 204MS/s. The ADC occupies 0.22mm² and dissipates 9.15mW at a 1.0V supply. The FoM of the ADC is 95.4fJ/conversion-step.