DESCRIPTION
The Microchip Technology Inc. 25AA640/25LC640/25C640 (25xx640*) is a 64K bit serial Electrically Erasable PROM. The memory is accessed via a simple Serial Peripheral Interface (SPI) compatible serial bus. The bus signals required 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.
Communication to the device can be paused via the hold pin (HOLD). While the device is paused, transitions on its inputs will be ignored, with the exception of chip select, allowing the host to service higher priority interrupts.

FEATURES
• Low power CMOS technology
   - Write current: 3 mA typical
   - Read current: 500 µA typical
   - Standby current: 500 nA typical
• 8192 x 8 bit organization
• 32 byte page
• Write cycle time: 5ms max.
• Self-timed ERASE and WRITE cycles
• Block write protection
   - Protect none, 1/4, 1/2, or all of array
• Built-in write protection
   - Power on/off data protection circuitry
   - Write enable latch
   - Write protect pin
• Sequential read
• High reliability
   - Endurance: 1M cycles (guaranteed)
   - Data retention: > 200 years
   - ESD protection: > 4000 V
• 8-pin PDIP, SOIC, and TSSOP packages
• Temperature ranges supported:
   - Commercial: (C) 0°C to +70°C
   - Industrial: (I) -40°C to +85°C
   - Automotive: (E) (25C640) -40°C to +125°C