HP Forum Archive 15

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static memory chips for HP48 upgrade Message #1 Posted by H.D. on 19 Sept 2005, 5:28 p.m. 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?

Re: static memory chips for HP48 upgrade Message #2 Posted by Randy on 19 Sept 2005, 5:59 p.m., in response to message #1 by H.D. Try M5M51008DFP70HIA0-ND from http://digikey.com $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...

Re: static memory chips for HP48 upgrade Message #3 Posted by Paul Brogger on 19 Sept 2005, 6:09 p.m., in response to message #1 by H.D. I got mine from www.futurlec.com . (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!

Re: static memory chips for HP48 upgrade Message #4 Posted by don wallace on 19 Sept 2005, 6:15 p.m., in response to message #1 by H.D. Hi H.D. Let me know in a day or two if you still can't source the parts you need. donwallace63@yahoo.com.au Best wishes! Don Wallace

Re: static memory chips for HP48 upgrade Message #5 Posted by H.D. on 19 Sept 2005, 8:15 p.m., in response to message #1 by H.D. 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, futurlec.com 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.

Re: static memory chips for HP48 upgrade Message #6 Posted by Paul Brogger on 20 Sept 2005, 9:10 p.m., in response to message #5 by H.D. www.futurlec.com -- 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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