Continue to Site

Welcome to

Welcome to our site! is an international Electronics Discussion Forum focused on EDA software, circuits, schematics, books, theory, papers, asic, pld, 8051, DSP, Network, RF, Analog Design, PCB, Service Manuals... and a whole lot more! To participate you need to register. Registration is free. Click here to register now.

EPROM/EEPROM compatibility

Not open for further replies.


Newbie level 1
Jun 19, 2015
Reaction score
Trophy points
Activity points
Hi gurus,

I'm a newbie and trying to find out if I can directly replace INTEL 27128 EPROM with drop in replacement EEPROM without modifications of the circuit. Obviously provided I use the same size chip and burn the bin into EEPROM starting at the same address. i.e. the content will be identical.

What would be the recommended EEPROM?


Many of the drop-in replacements for EPROM DIP packages are becoming increasingly scarce.

Can you program flash devices?

If so, there are recommended Flash drop-in replacements available for the 27C128 and larger series EPROMs.

I've not examined an Intel 27128 in quite a while, so do your research and double check the pinout, that being said if a 27C128 is a drop-in replacement, you might consider the SST27SF512, which was specifically designed as a drop-in replacement for 27C128 to 27C512.

They are still available from a few distributors:

Auto Enthusiast Moates C2 SST 27SF512 Chip

SST27SF512 Datasheet

Device Operation

The SST27SF512/010/020 are a low cost flash solution
that can be used to replace existing UV-EPROM, OTP,
and mask ROM sockets. These devices are functionally
(read and program) and pin compatible with industry
standard EPROM products.
In addition to EPROM func-
tionality, these devices also support electrical Erase
operation via an external programmer. They do not
require a UV source to erase, and therefore the pack-
ages do not have a window.

However, be on the alert of inexpensive Chinese knockoffs, apparently due to the scarcity of these devices, there are a number of Chinese vendors rebranding one time programmable (OTP) devices as genuine SST27SF512s. Needless to say, once they are programmed, there is no second chances.

Genuine SST27SF512s have laser inscribed logos and part numbers, so watch out devices with common silk screening print.

You may need to relocate the program code to address 0xC000 during programming.

Also, check with some of the auto enthusiast forums, as they routinely replace the legacy EPROMs in automobiles with custom code.


Not open for further replies.

Part and Inventory Search

Welcome to