Question

How can ultraviolet erasable PROMs be recognized?

(a) There is a small window on the chip

(b) They will have a small violet dot next to the #1 pin

(c) Their part number always starts with a “U”, such as in U12

(d) They are not readily identifiable, since they must always be kept under a small cover

The question was asked in a national level competition.

I want to ask this question from Programmable Read Only Memory topic in portion Memory Devices of Digital Circuits

Answer 1

Correct choice is (a) There is a small window on the chip

Best explanation: An ultraviolet erasable PROMs have small window on the chip with black marked. Such type of PROMS are called EPROMS which are cleared by exposing it to UV radiation. They are re-programmable.