The M27C256B is a 256Kbit EPROM available in UV (ultra violet erase) and OTP (one time programmable) ranges. It is ideally suited for microprocessor systems and is organized as 32,768 x 8 bits. The FDIP28W (window ceramic frit-seal package) has a transparent lid which allows the user to expose the chip to ultraviolet light to erase the bit pattern. A new pattern can then be written to the device by following the programming procedure. For applications where the content is programmed only one time and erasure is not required, the M27C256B is offered in PDIP28, PLCC32 and TSOP28 (8 x 13.4 mm) packages.
The M27C256B is a 256‑Kbit EPROM offered in UV (ultraviolet erase) and OTP (one‑time programmable) versions. It is organized as 32,768 × 8 bits and is supplied in FDIP28W, PDIP28, PLCC32 and TSOP28 packages. The document provides electrical characteristics, absolute maximum ratings, operating modes, programming procedures and system design recommendations.
Key features include a 45 ns access time, low‑power standby mode (100 µA), and a programming voltage of 12.75 V. Detailed tables list voltage ranges, leakage currents, timing parameters and mechanical dimensions for each package type, helping designers integrate the device into microprocessor systems.
| Access Time | 45 ns |
|---|---|
| Active Supply Current (Read) | 30 mA |
| Standby Current | 100 µA |
| Programming Voltage | 12.75 V ±0.25 V |
| Programming Time per Word | 100 µs |
| Supply Voltage (Read) | 5 V ±10 % |
| Ambient Operating Temperature | -40 °C to 125 °C |
| Storage Temperature | -65 °C to 150 °C |
| Package Types | FDIP28W, PDIP28, PLCC32, TSOP28 |
The device requires a programming voltage of 12.75 V ±0.25 V.
In standby mode the M27C256B draws about 100 µA.
The access time is specified as 45 ns.
It is available in FDIP28W, PDIP28, PLCC32 and TSOP28 packages.