A 64-bit 100-MHz multimedia DSP core has been designed using 0.15-µ m CMOS technology. An improved Auto-Backgate-Controlled MT-CMOS (ABC-MT-CMOS) circuit with a charge pump is adopted to suppress the standby leakage current. The dynamic active current of whole chip was simulated to optimize the size of a switch for a power supply control. The DSP core chip, which integrates 300-kgate Logic, 64-kbyte SRAM and charge pump circuit, has 8-µ A standby leakage current. The reduction rate is 1/250.