UT28F256 is a 32K x 8 programmable memory device that supports industry standard programmers, has 45ns and 40ns maximum address access time, TTL compatible input and TTL/CMOS compatible output levels, three-state data bus, low operating and standby current
The UT28F256 is a 32K × 8‑bit radiation‑hardened PROM offering asynchronous operation, low standby current, and fast address access times of 45 ns (40 ns version). It is designed for high‑speed systems operating in harsh radiation environments and features TTL‑compatible inputs and CMOS/TTL‑compatible outputs.
The device is available in 28‑lead flat‑pack or DIP packages, supports a supply voltage of 5 V ± 10 % (4.5‑5.5 V), and can tolerate a total ionizing dose of up to 1 E6 rad(Si). Ordering requires specification of lead finish, total dose, and access‑time options.
| Memory size | 32K × 8 bits |
|---|---|
| Maximum address access time | 45 ns (40 ns version) |
| Supply voltage | 5.0 V ±10% (4.5 V‑5.5 V) |
| Operating current | 125 mA @25 MHz |
| Standby current | 2 mA (post‑rad) |
| Total radiation dose tolerance | 1 E6 rad(Si) |
The device provides a maximum address access time of 45 ns, with a faster 40 ns version available.
It operates from a 5 V supply with a ±10 % tolerance, i.e., between 4.5 V and 5.5 V.
The PROM is rated for a total ionizing dose of up to 1 E6 rad(Si).