Finding IC Chip for 7-Segment Hex Decoder - SMD Package

  • Thread starter Jiggy-Ninja
  • Start date
  • Tags
    Ic
In summary, the author is looking for a chip that can convert a nybble to BCD, and is having difficulty finding one.
  • #1
Jiggy-Ninja
309
1
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" 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:
Engineering news on Phys.org
  • #2
You could do it in random logic. It doesn't require that many gates.
 
  • #3
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.
 
Last edited:
  • #4
small microcontroller?
 
  • #5
@ 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".
 
  • #6
Jiggy-Ninja said:
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
 
  • #7
KingNothing said:
@ 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".

carlgrace said:
Or try this:

http://cgi.ebay.com/1-pc-74LS47-BCD-7-Segment-Decoder-DIP-16-pin-IC-/170467158261
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.
 
  • #8
Jiggy-Ninja said:
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.
 
  • #10
Jiggy-Ninja said:
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.
 
  • #11
carlgrace said:
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:
7-segments_Indicator.gif

And can't find a chip anywhere to do it.
 
  • #12
Jiggy-Ninja said:
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:
7-segments_Indicator.gif

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...
 
  • #13
carlgrace said:
...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?
 
  • #14
Jiggy-Ninja said:
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.
 
  • #15
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" and just pressing the IC onto it while it's in the programmer work in a pinch?
 
Last edited by a moderator:
  • #16
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.
 

1. What is an IC chip?

An IC (integrated circuit) chip is a small electronic device that contains millions of tiny components, such as transistors, resistors, and capacitors, all etched onto a tiny piece of silicon. It is used to perform specific functions in electronic circuits, such as amplifying signals, storing data, or decoding information.

2. What is a 7-segment hex decoder?

A 7-segment hex decoder is a type of IC chip that is specifically designed to convert binary or hexadecimal input signals into a form that can be displayed on a 7-segment display. It takes in a binary or hexadecimal number and converts it into a pattern that can be displayed on the 7-segment display to represent that number.

3. What is an SMD package?

An SMD (Surface Mount Device) package is a type of packaging used for electronic components, including IC chips. It is designed to be mounted directly onto the surface of a printed circuit board, rather than being inserted into holes like through-hole components. SMD packages are smaller and more compact, making them ideal for use in smaller electronic devices.

4. How do I find the right IC chip for a 7-segment hex decoder in an SMD package?

The best way to find the right IC chip for a 7-segment hex decoder in an SMD package is to search for the specific part number of the chip. This can usually be found in the datasheet or on the manufacturer's website. You can also consult with a supplier or distributor who specializes in electronic components to help you find the correct chip for your needs.

5. Where can I purchase an IC chip for a 7-segment hex decoder in an SMD package?

IC chips for 7-segment hex decoders in SMD packages can be purchased from a variety of sources, including online electronics retailers, electronic component distributors, and directly from the manufacturer. It is important to ensure that you are purchasing from a reputable source to ensure the quality and authenticity of the chip.

Hot Threads

Recent Insights

Back
Top