This paper describes a 16-bit fiied point digital signal processor (DSP), which is targeted for telecommunication applications such as modems or low-bitrate speech CODECs. A variable pipeline multiplieraccumulator (MAC) unit and several additional circuits such as a dual-purpose shift register are used to improve performance per MIPS. The DSP chip is fabricated with 0 5 pm CMOS process and achieves 40 MIPS and 80 MOPS-peak performance at 3.0V. PSI-CELP (Pitch Synchronous Innovation Code Excited Linear Prediction) speech CODEC can be implemented on this DSP with enough margin.