This data sheet introduces TMS27C256 series and TMS27PC256 series 32768 bits (262144 bits), ultraviolet (UV) light erasable, electrically programmable read-only memories (EPROMs) and programmable read-only memories (PROMs).
The TMS27C256 and TMS27PC256 are 32768 by 8-bit read-only memories (ROMs) fabricated using power-saving CMOS technology. The TMS27C256 is an ultraviolet (UV) light erasable electrically programmable ROM (EPROM), while the TMS27PC256 is a one-time programmable (OTP) PROM. Both devices are pin compatible with existing 256K MOS ROMs, PROMs, and EPROMs and operate from a single 5-V power supply in read mode.
| Technology | CMOS |
|---|---|
| Operating Voltage | 5 V |
| Programming Voltage | 13 V |
The signature code is 9704, where 97 is the manufacturer code and 04 is the device code.
The nominal programming time is four seconds using a Vpp of 13 V and a Voc of 6.5 V.
Yes, it is erased by exposing the chip to a high intensity ultraviolet light with a wavelength of 2537 A.