The AT28C256 is a high-performance electrically erasable and programmable read-only memory. It features fast read access time, automatic page write operation, fast write cycle times, low power dissipation, and more.
The AT28C256 is a 256‑Kbit electrically erasable programmable read‑only memory organized as 32 K × 8 bits. It offers fast 150 ns read access, low power consumption, and a 64‑byte page write capability. The device is compatible with both CMOS and TTL logic levels and operates from a single 5 V supply.
The datasheet provides pin configurations, timing diagrams, electrical characteristics, operating temperature ranges, and protection features. Both hardware and software data‑protection mechanisms are described, along with optional chip‑erase mode and device‑identification EEPROM space.
| Memory size | 256 Kbit (32 K × 8) |
|---|---|
| Read access time | 150 ns |
| Page write cycle time | 3 ms or 10 ms max |
| Page size | 64 bytes |
| Supply voltage | 5 V ±10 % |
| Standby current (CMOS) | 200 pA |
| Active current (CMOS) | 50 mA |
| Data retention | 10 years |
| Operating temperature (commercial) | 0 °C to 70 °C |
| Operating temperature (industrial) | -40 °C to 85 °C |
| Operating temperature (military) | -55 °C to 125 °C |
The device operates from a single 5 V supply with a tolerance of ±10 %.
Up to 64 bytes can be written in a single page write operation.