AT29C040A is a 5V in-system programmable and erasable read-only memory (PEROM) with features such as fast read access time, sector program operation, hardware and software data protection, etc.
The AT29C040A is a 5‑volt‑only in‑system flash programmable and erasable read‑only memory (PEROM) organized as 4 Mbits (512 K × 8). It provides fast 90 ns read access, low active current (40 mA) and ultra‑low standby current (100 pA), and can endure over 10 000 program cycles per sector. The device includes hardware and software data‑protection features, boot‑block lockout, and a product‑identification mode.
The datasheet details pin configurations for 32‑lead PLCC and TSOP packages, block diagram, device operation (read, byte load, program), timing specifications, absolute maximum ratings, and electrical characteristics such as input/output voltage levels and leakage currents. Package dimensions and mechanical drawings are also provided.
| Read Access Time | 90 ns |
|---|---|
| Supply Voltage | 5 V ±10% |
| Sector Size | 256 Bytes |
| Number of Sectors | 2048 |
| Active Current | 40 mA |
| Standby Current | 100 pA |
| Endurance | >10,000 cycles per sector |
| Input High Voltage (TTL) | 2.0 V |
| Output High Voltage (CMOS) | 4.2 V |
Each sector contains 256 bytes of memory.
The device uses DATA polling; the I/O6 pin toggles until the program cycle completes, after which valid data is presented.
The device is programmed with 5‑volt‑only commands; no higher input voltage is needed.
It has two 16‑KB boot blocks that can be locked out individually.