This paper presents a time-efficient dither-injection digital circuit in digital domain for pipelined successive approximation register analog-to-digital converter (SAR ADC). Compared with the conventional dither injection method, the proposed method can achieve faster injection speed and reduce the disturbance during the quantization of the ADC. Only 1 LSB dither injection is discussed in this method. Simulation results show more than 8 times speed improvement comparing to the conventional configuration.