The DS1644-120 is an analog integrated circuit, manufactured by Analog Devices, that is designed for reliable, low-cost, high-endurance serial presence detect (SPD) applications. It is a 256-Kbit CMOS nonvolatile, static random-access memory (NVRAM) that is organized as 32K x 8 bits. It is packaged in a 20-pin SSOP, SOIC, and PDIP. The device is powered by a 2.5 to 5.5 V single-voltage supply and operates from 2.2 to 5.5 V, making it ideal for use in low-voltage applications. Its onboard write-protect circuitry allows for secure and reliable data storage. The DS1644-120 can provide up to 10 years of data retention at 25°C and allows for up to 1 million write/erase cycles. It is ideal for applications that require robust and reliable storage of large sets of SPD data.