Microchip introduced the 23A640, 23K640 (23X640), 23A256 and 23K256 (23X256) 8- and 32-Kbyte stand-alone serial SRAM devices. The devices feature an industry-standard SPI interface and enable increased design flexibility, while reducing design and production costs, and time to market. Microchip’s serial SRAM devices are all available in 8-pin SOIC, PDIP and TSSOP packages. In 10,000-unit quantities, the 23X640 devices are priced at $0.48 each for the SOIC package; $0.50 each for the PDIP package, and $0.51 each for the TSSOP package. The 23X256 devices are priced in 10,000-unit quantities at $0.90 each for the SOIC package; $0.91 each for the PDIP package, and $0.93 each for the TSSOP package.
The 23A640 and 23A256 devices have an operating voltage range of 1.7 – 1.95V. The 23K640 and 23K256 devices have an operating voltage range of 2.7 – 3.6V. All of the devices are well suited for applications involving bulk data transfers; DSP and other math algorithms (e.g. FFT and DFT); audio/video, speech encoding, VoIP and Internet applications. Specific examples include applications in the consumer (Internet appliances, Internet radios and printers); industrial (utility meters, vending machines); and medical markets (portable patient-monitoring devices), among others.
Microchip’s serial SRAM devices provide a simple and inexpensive way for designers to add more RAM to their application while keeping the same MCU, or even using a smaller one if replacing parallel external RAM with serial RAM. In addition, the devices feature a bus speed of 20 MHz for fast access, and low operating and standby currents to help extend battery life. They are available in 8-pin packages but only use four MCU pins, compared with 16 to 24 pins for parallel RAM.