Deglitching Micros on Plug-in Proto Boards

snipped-for-privacy@gmail.com wrote in news: snipped-for-privacy@googlegroups.com:

You may be running into die size limitations. There isn't a lot of die attachment area on a DFN-8 or QFN-16 package leadframe. Large FLASH and RAM implies larger die area.

If they can fit it in DIP-28, I am sure they can fit it in DIP-14. DIP-28 and DIP-14 have the same width, just longer. I can live with less pins, since most of them are RP (repurpose) pins anyway.

snipped-for-privacy@gmail.com wrote in news: snipped-for-privacy@googlegroups.com:

Unfortunately that's not the way the market goes. Those companies that still provide new LSI chips in DIP packages mostly do so as a convenience for the developer/experimentor. Many have given up doing so and only offer SMD packages. If a viable SMD package with a comparable pin count doesn't exist, a new MCU just isn't going to be packaged in DIP.

If you *really* need a 0.3" width small DIP package you'll have to start with a 28 pin part in a 28/QFN-S package (which is only 5x5mm) and a custom breakout board with two 0.1" pitch headers seperated by 0.3". There's fractionally under 7mm between the rows of header pins giving just under 1mm clearance either side. The QFN diagonal size is 7.07mm so you can just squeeze it in on the diagonal with its corners in between two header pins to ease routing. You get to choose which pins to break out.

Microchip have 22 current 16 bit PICs with 128K or more FLASH in 28/QFN-S packages so the only thing stopping you is your reluctance to adopt SMD prototyping . . . . .

Particularly SRAM. Flash is pretty small. I do see newer processors with QFN-32s with 64K and 128K flash (256K?).

just longer. I can live with less pins, since most of them are RP (repurpose) pins anyway.

it seesm to me that you could saw one end off a 28-pin pic and it would still work. ( the end with pins 11 to 18 )

As long as you don't cut the die in half. Cutting pin 13 (VDD) might not work either. If volume is high enough, might be easier to get the die and custom pack in DIP-16.

die should be central, pin 13 is a GPIO, power pins are near the middle.

Pin 13 is VDD for PIC32MX. Pin 17 is MOSI for Atmega328 Pin 1 is Reset for both.

So, can't really cut much from either end.