06-17-2014 11:46 PM
Im trying to update an old project that used a 24 pin dip CPLD. The CPLD that was used is no longer availible and I woulld like to replace it.
The chip requiremet: 24 pin dip, 5V Vcc and Schmitt triggers on the I/O ports would be helpfull.
I tried looking though the Xilinx CPLD families but didnt see anything like that.
Can anyone recommend a replacement?
06-18-2014 12:07 AM
06-18-2014 12:07 AM
06-18-2014 10:53 AM
You won't find any parts in DIP packaging or with +5V power supply. However there may be some with 5V tolerance. If you really need a drop-in replacement you probably have to look at building a small board with voltage translators, etc.
Here's an example, although they don't go as small as 24 pins:
06-19-2014 12:35 AM
Just for interest sake, why is DIP pacaging no longer used?
I've noticed the past few days everything is moving to 3.3V and lower power supplies and almost everything is surface mount.
I'll move away from the idea of finding a drop in replacement, just redesign with new technology chips :)
06-19-2014 11:03 AM
There may be other reasons, but here's some big ones:
DIPs are large compared to the size of the die in them. This increases required board area.
DIPs have very long package leads from the die to the pin. This increases lead inductance and can causes unacceptable ground bounce in devices with fast slew rates.
DIPs are through-hole, requiring a secondary soldering process on an otherwise all-SMT board. It also means that the device takes up valuable real estate on both board surfaces.
DIPs have a very limited maximum practical size in terms of pin count compared to newer packaging. And the larger the pin count, the worse the above-mentioned effects.
Devices driving new technology are becoming more miniaturized. Desktop PC motherboards no longer account for a majority of even PC-related chip sales. Devices like smart phones and other embedded systems require ever-shrinking package technology.
06-19-2014 11:03 PM - edited 06-19-2014 11:05 PM
maybe these GOP modules might be useful for your application:
There are similar boards with other CPLD-Types (XC9500XL and Coolrunner XPLA3) in the shop too, or even FPGAs (Spartan3).
And for 40 pin DIL replacements there are GODIL Modules with different FPGAs available.
Have a nice synthesis