One-time programmable behavior – can a programmed PROM be changed later by applying a small electrical charge?

Introduction / Context: Memory families differ in whether content can be altered after initial programming. PROMs (programmable read-only memories) are designed for one-time programming, unlike EPROM/EEPROM/Flash which support erasure and rewriting. This item checks whether PROM contents can be changed electrically after programming.

Given Data / Assumptions:

• PROM programming creates permanent physical changes (fuse blown or antifuse formed).
• No erase mechanism is provided by design.
• We are not discussing EPROM or EEPROM.

Concept / Approach: Because PROM cells are altered irreversibly during programming, there is no subsequent electrical operation that restores the original state. Therefore, the assertion that a small electrical charge can change PROM contents later is false. Any device that can be erased by electrical means is not a classic PROM; it is an EEPROM or Flash device.

Step-by-Step Solution:

Verification / Alternative check: Datasheets describe PROMs as OTP (one-time programmable). In contrast, EPROMs mention UV windows; EEPROMs/Flash list electrical erase commands. PROMs lack such sections entirely.

Why Other Options Are Wrong: UV erasers affect EPROM, not PROM. Reversing charge is inapplicable to fuse links. Temperature does not provide an erasure mechanism.

Common Pitfalls: Mixing up acronyms (PROM vs EPROM vs EEPROM) and assuming all “programmable ROMs” are rewritable.

Final Answer: Incorrect