# Finding an IC chip

I'm designing a simple little circuit board for prototyping purposes (a byte displayer using a pair of 7 segment displays).

Problem is, I can't find a binary->7-segment hex decoder still being made anywhere. I found a couple leads on Google, but Digikey and Mouser showed them as discontinued. I'd prefer a small SMD package (SOIC or TSSOP), since I''d like the board to be as small as possible.

If not, I'm willing to program an http://ca.mouser.com/ProductDetail/Atmel/ATF16LV8C-10XU/?qs=sGAEpiMZZMvwLjDpJZyitOLIDNjXIEtrQxy19NCE7eA%3d" [Broken] to do the job. I have access to a programmer and WinCUPL software, but it only fits DIP packages. How do you program an SOIC or TSSOP without some expensive $85 adapter socket? Last edited by a moderator: ## Answers and Replies You could do it in random logic. It doesn't require that many gates. You mean with 7400s, '04s, and whatever? Unless I did my k-maps wrong or there's some technique I don't know, I'd need 7 OR gates with 3-4 inputs each, and 20 at least 20 AND games with 3-4 inputs each. with the smallest chip size possible, that's a lot of board space with a lot of traces running around. And it's be hell to solder. And that's just with DCBA inputs; I'm not counting RBI, LT, or CE because I don't really care about those for this application. Why the hell are the programmers so expensive? I can hardly find any for <$100.

A Parallel in/out EEPROM would work, as log as it wasn't much bigger than necessary (16x8 is all that's needed), cheap enough, easy to program without fancy parts.

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small microcontroller?

@ Digikey:
296-2079-5-ND
296-3528-1-ND
568-3125-5-ND

All of these are under a dollar, in stock, and have a minimum quantity of 1. Digikey has tons of them - try a search for "BCD-7".

You mean with 7400s, '04s, and whatever?

Unless I did my k-maps wrong or there's some technique I don't know, I'd need 7 OR gates with 3-4 inputs each, and 20 at least 20 AND games with 3-4 inputs each. with the smallest chip size possible, that's a lot of board space with a lot of traces running around. And it's be hell to solder.

And that's just with DCBA inputs; I'm not counting RBI, LT, or CE because I don't really care about those for this application.

Why the hell are the programmers so expensive? I can hardly find any for <$100. A Parallel in/out EEPROM would work, as log as it wasn't much bigger than necessary (16x8 is all that's needed), cheap enough, easy to program without fancy parts. Or try this: http://cgi.ebay.com/1-pc-74LS47-BCD-7-Segment-Decoder-DIP-16-pin-IC-/170467158261 @ Digikey: 296-2079-5-ND 296-3528-1-ND 568-3125-5-ND All of these are under a dollar, in stock, and have a minimum quantity of 1. Digikey has tons of them - try a search for "BCD-7". I already found (and bookmarked) several BCD->7-segment decoders. I've had no trouble finding several different kinds of those. I'm looking for a Hexadecimal->7 segment decoder. I can't find that anywhere. I already found (and bookmarked) several BCD->7-segment decoders. I've had no trouble finding several different kinds of those. I'm looking for a Hexadecimal->7 segment decoder. I can't find that anywhere. Oh, OK. Binary to BCD is trivial (and doesn't use many chips). http://www.electro-tech-online.com/...208347753-binary-bcd-converter-binary-bcd.gif Then put the output into one of the bcd-to-7-segment display chips KingNothing found. I'm trying to get the haxadecimal to display on one 7-segment, not two. That solution doesn't help. I think you're misunderstanding me. The circuit in that .gif converts a nybble to BCD. Use two of them to convert your byte. Then concatenate the outputs and send to the BCD-to-7-segment display driver. I think you're misunderstanding me. The circuit in that .gif converts a nybble to BCD. Use two of them to convert your byte. Then concatenate the outputs and send to the BCD-to-7-segment display driver. At the moment, I'm not looking to convert binary to BCD, thought that's a good backup plan if I can't do what I'm trying to do. I'm trying to get a display like this: And can't find a chip anywhere to do it. At the moment, I'm not looking to convert binary to BCD, thought that's a good backup plan if I can't do what I'm trying to do. I'm trying to get a display like this: And can't find a chip anywhere to do it. ...and the simplest way to do that is a binary ripple counter driving a binary to BCD converter... ...and the simplest way to do that is a binary ripple counter driving a binary to BCD converter... I don't get it. Most of the BCD->7-segment decoders I've found show either gibberish or blanks for anything above 9. How does your scheme let me display A-F? I don't get it. Most of the BCD->7-segment decoders I've found show either gibberish or blanks for anything above 9. How does your scheme let me display A-F? You may be right. I have only used one 7-segment display and we designed our own decoder (for a lab class) that accepted A-F. You want the DM9368. It will do the job. There is one here: http://cgi.ebay.com/DM9368N-Integrated-Circuit-x-1-pieces-DM9368-/150583168277 But you may be able to find it elsewhere, cheaper, if you do some digging. Good luck. I believe that's one of the chips I came across that's discontinued.$30 is a ridiculous price for a chip as simple as this, and I don't really know where else to look.

For programming a surface-mount PLD, would getting a board like http://www.epboard.com/eproducts/protoadapter.htm" [Broken] and just pressing the IC onto it while it's in the programmer work in a pinch?

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I agree, $30 is ridiculous. There are FPGAs that cost around$7 and microcontrollers less than \$2. Good luck, sorry I could not be of more help.