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Best IC Calculator Question Answered

I am looking for a chip just like the ones used in any calculator that does multiplication addition and subtraction. THe device i am looking to build has to be as thin as a credit card have a 8 character segment lcd and only be able to do addition and subtraction. so i need to be able to have buttons" 1 to 0 + - and = and . "nothing more. i looked at some attiny ics but they require a another ic to drive the lcd. also the the data entered need to stay in if the power of the ic goes out. most calculators have only one ic, any idea what the best ic for this application will be? thank you in advance.

i need something this small.

http://www.logopremiums.com/calculator-ballpoint-pen-HWK922LP.jpg

Thank you

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virgiltu (author)2013-02-06

No i am building a different module. and the only reason i need only the chip is because i have to fit it in a much smaller package.

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Goodhart (author)virgiltu2013-02-06

smaler than say, a watch? Yes, they make calculators that small already

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virgiltu (author)Goodhart2013-02-06

0.8 mm thin. so yes much smaller.

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Goodhart (author)virgiltu2013-02-07

Good Luck with that. Traces can be made very small and thin, but certain componants are normally not unless included inside a CPU chip or such.

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virgiltu (author)Goodhart2013-02-07

so far i found displays that are 0.40mm and the chip die only is usually 0.50 if not smaller. most parts now come in 0402 packages that is 0.1mm x 0.1mm so i think that will be ok. I just thouhgt that maybe somebody on here would know a chip that i can get. but i think i found my answer on google. Thanks for the ideas.

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Goodhart (author)virgiltu2013-02-07

These are not easy to work with without proper equipment though.

0402 (1005 metric): 1.0 mm × 0.5 mm (0.039 in × 0.020 in). Typical power rating for resistors = 0.1 [6] or 0.062 watt

SOT-953: 1 mm × 1 mm × 0.5 mm body: five terminals
SOT-963: 1 mm × 1 mm × 0.5 mm body: six terminals

From Phillips Semiconductor

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virgiltu (author)Goodhart2013-02-07

so far i found displays that are 0.40mm and the chip die only is usually 0.50 if not smaller. most parts now come in 0402 packages that is 0.1mm x 0.1mm so i think that will be ok. I just thouhgt that maybe somebody on here would know a chip that i can get. but i think i found my answer on google. Thanks for the ideas.

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virgiltu (author)2013-02-06

After reading around i noticed that i can actually buy a chip that requires no parts other then making the pcs buttons, lcd and battery. i keep finding chips from the 1970s but i cant seem to find anything new. that i can get in a really small package.

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user

You are probably looking for SMD and using the wrong prefix.

SMD = Surface Mount Device

Most SMDs or SO packages are prefixed differently 74F08 instead of SN74LS08 in the DIP package.

Give me the device part number you have been using and I might be able to find it.

You can also try Mouser Electronics I got 100 transistors for the same price as a small package at Radio Shack.

http://ca.mouser.com/search/Default.aspx

Joe

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Josehf Murchison (author)2013-02-06

Buy the pen and salvage the chip

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user

i thought that way to, but it is under an epoxy film. finding the right chip will be much better. most of these have a lot of functionalities that are disables in the every day calculator. like the last value save. plus i pcb layer im installing it on is 0.45mm thick.

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caitlinsdad (author)2013-02-06

Are you reinventing the wheel? I don't think you can DIY something small enough that the cheap import electronic companies have already done. Look up "credit card calculator" for a whole bunch, they are even solar powered.

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