static memory chips for HP48 upgrade


I can't seem to find these chips: static ram, 128kB (128kB x 8), SO32, low power on idle, 70ns-85ns access time.

Does anyone know how I can buy, say, 3 of them without having to make a minimum order of $100.00 as is required by many distributors who actually have them?


Try M5M51008DFP70HIA0-ND from $4.50 each, in stock.

I have some older Toshiba TC551001CF's that you may have if you don't mind desoldering them from a board...


I got mine from .

(I don't know if I got parts that conform exactly to your specs, but they work.)

At the time I purchased (several years ago!) Futurlec would take a no-minimum order. I'll leave it to interested parties to discover whether that's still true.

I do remember being pleased with their prompt service. (Again, this was several years ago.)

Good luck!


Hi H.D.

Let me know in a day or two if you still can't source the parts you need.

Best wishes!

Don Wallace


Oh, I forgot to mention that I need a 128kB chip (the one posted above is a 1MB chip) since I'm upgrading my 48G (starts with 32kB ram). I was hoping to upgrade to 384kB (128kB main ram, 128kB port 1, and 128kB port 2).

So far, has all the _other_ parts I need (74HC00, 74HC174, 104 and 143 SMD thin film resistors) but nothing resembling 128kB (8-bit) static ram chips.

Sadly, no distributor has a search feature that allows descriptive words as opposed to knowing part numbers. Mouser electronics is an exception, but they too do not carry the 128kB sized ram chips.

#12 -- Components -- Integrated Circuits -- Memory -- RAMs

(I couldn't resist.)

Two parts are listed: a "628128" and a "681000", each 128Kx8 CMOS static RAM for $5.90 and $2.90/piece (respectively), in stock. (With a Hitachi data sheet available online for the former.) They're referred to as 1 megabit (not megabyte) chips because 128K words x 8 bits ~= 1 million bits. They seem to come in several packages, so make sure they have available (and that you order) the surface mount, dual inline package.

I think that one of those parts is the same type of which I bought several way back when, and they're working today.

Good luck!

[ . . . and I've finally got 'round to reading the other thread, so you already know most of the above. Sorry!]

Edited: 20 Sept 2005, 10:22 p.m.

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