What is a PEROM ?

Do you have a question? Post it now! No Registration Necessary.  Now with pictures!

Threaded View
I saw these mentioned online somewhere and wondered what this kinda chip is
? Is it in the same family as EPROM EEPROM, etc ?


Re: What is a PEROM ?

Skeleton Man wrote:
Quoted text here. Click to load it

These are the types I'm familiar with.

1) Mask ROM. These are used for permanent read-only
    memory. There is a one time fee, to make the mask for
    the ROMs. Typically, you might do this, if you needed
    100,000 identical devices, like firmware for something.
    For smaller production runs, use something else.

2) Fuseable ROM. Its been many years since I used these.
    These can be programmed once, and use something
    like Titanium-Tungsten. In the lab, I burned up $3000
    worth of these, while doing product development. Great
    fun when the boss finds out. They're not reprogrammable.

Now starts the devices based on Flash technologies.

3) OTP - this would be a flash memory which is one
    time programmable. It would allow, for example,
    a custom serial number to be placed in each component,
    as well as, say, some firmware. These might be used
    for the SPD chip on memory DIMMs, as an example. No
    erase options available.

4) EPROM - eraseable programmable read only memory.
    By means of a UV window and a UV light source, the
    device can be erased and returned to the all 1's state.
    More common in the 32 pin DIP era. Many happy hours
    spent with the UV light and trays of chips.

5) EEPROM - electrical eraseable EPROM. No window on this
    one, it can be erased electrically, with the right
    voltage applied. These would be used on motherboards.

Your "PEROM" appears to be another way of stating (4).
Until you mentioned it, I didn't even know anyone was
using a term like that. It's always been "EPROMs" with
my friends.

Both (4) and (5) have limits to the number of write/erase


Re: What is a PEROM ?

Skeleton Man wrote:
Quoted text here. Click to load it

A PEROM is a dyslexic EPROM -- it automatically applies random
transpositions to the data stored in it. ;-0

John McGaw
[Knoxville, TN, USA]

Site Timeline