On 2/14/26 11:48, Neil Cherry wrote:
62256s are common, and are the same format as a 27256, with a slight pinout difference. (A14 vs. /WR vs. Vpp)
There are 62128s, but a very different kind, not the same format as a 27128 EPROM. The 62128 is 128K*8, while the 27128 is 16K*8. This is a source of confusion when people compare them to 62256s, which are 32K*8.
Ah the lovely 62128 16kx8 SRAM, never could figure out why they were made when the 62256 was common place. Didn't seem to fit the pattern of the 2K, 8K, & 32k SRAM at the time.
The 62128 16Kx8 do exist but they are rare. I don't have any (I think). Everyone is now using the number as 128Kx8 SRAM much more confusion.
As Dave notes 6116, 6264 and 62256 are the common SRAM in JDEC form. Not a 100% match for the equivalent ROM.
You can get pulls from Ebay but there are other who sell pulls or old stock such as:
Huh! I've never seen any of those, in anything, anywhere. I wonder if they are 62256 dies that were binned. -Dave -- Dave McGuire, AK4HZ New Kensington, PA