DESCRIPTION
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.

FEATURES
• 1MHz Clock Rate
• SPI Modes (0,1 & 1,0)
• 256 X 8 Bits
    —4 Byte Page Mode
• Low Power CMOS
    —10µA Standby Current
    —3mA Active Current
• 2.7V To 5.5V Power Supply
• Block Lock Protection
    —Protect 1/4, 1/2 or all of E2PROM Array
• Built-in Inadvertent Write Protection
    —Power-Up/Power-Down protection circuitry
    —Write Latch
    —Write Protect Pin
• Self-Timed Write Cycle
    —5ms Write Cycle Time (Typical)
• High Reliability
    —Endurance: 100,000 cycles per byte
    —Data Retention: 100 Years
    —ESD protection: 2000V on all pins
• 8-Lead PDlP Package
• 8-Lead SOIC Package