X25021

The X25021 is a CMOS 2048-bit serial E²PROM, internally organized as 256 x 8. The X25021 features a Serial Peripheral Interface (SPI) and software protocol allowing operation on a simple three-wire bus. The bus signals are a clock input (SCK) plus separate data in (SI) and data out (SO) lines. Access to the device is controlled through a chip select (CS) input, allowing any number of devices to share the same bus.

The X25021 also features two additional inputs that provide the end user with added flexibility. By asserting the HOLD input, the X25021 will ignore transitions on its inputs, thus allowing the host to service higher priority interrupts. The WP input can be used as a hardwire input to the X25021 disabling all write attempts, thus providing a mechanism for limiting end user capability of altering the memory.

The X25021 utilizes Xicor's proprietary Direct Write™ cell, providing a minimum endurance of 100,000 cycles per byte and a minimum data retention of 100 years.