Asynchronous SRAMs Renesas Electronics Asynchronous SRAMs are based on high-performance, high-reliability CMOS technology. The technology and innovative circuit design techniques provide a cost-effective solution for high-speed async SRAM memory needs. Fully static asynchronous circuitry requires no clocks or refresh for operation. Renesas delivers asynchronous SRAM in RoHS 6/6-compliant (Green) packaging using industry-standard package options.