Do you really need to match the exact chip? I think in practice, sharing across the family is good enough.
Lets focus on two formats. I’m sure you know AVR DD has the 28-pin PDIP that we’ve talked about before. But the 20-pin VQFN (3mm x 3mm) is perhaps what you’re not familiar with. Its electrically compatible with the 28-pin PDIP (just 20-pins instead) and shares the data-sheet / features and everything (same RAM, same assembly, same datasheets and properties).
So my overall argument is that the 28-pin PDIP should be a fine-enough prototype for a 20-pin VQFN final product. Maybe with an intermediate prototype with a 20-pin SOIC (SOIC is a good deal easier to solder after all) if you wanted something that matched pin-for-pin that didn’t require quite the same level of difficulty to solder.
Note that the 20-pin VQFN AVR32DD20 (https://www.digikey.com/en/products/detail/microchip-technology/AVR32DD20-I-REB/16643834) is at that $1 mark, sure a bit more expensive than ATTiny4 but if its space you’re concerned about, the VQFN package at 3mm x 3mm is damn near the 2.8mm x 2.9mm of the SOT-23 6-pin. Aside from the pain in the ass it is to work with leadless (though doable on hobby budgets with a hot-air gun, pancake griddle and solder paste), its not like these small 3mm x 3mm packages are outside of our reach!
With knowledge that modern Microchip chips offer VQFN-20 chips in the 3mm x 3mm footprint, it does feel like SOT-23 6 packages like the ATTiny4 are kind of obsolete. After all, might as well shove 20-pins into that space with today’s level of miniaturization.
I guess the ATTiny4 is cheaper though (under 50-cents in bulk). But the variety of packages offered here by Microchip is basically just for prototyping. SOIC-14, TQFP-32, PDIP-28, SSOP-28… these are all far larger than the VQFN-20 (3mm x 3mm) and VQFN-32 (5mm x 5mm) footprints that would go into a final productized design.
This seems really important to you. It isn’t to me.
I am not going to go back to buying DIP packages of chips. These little adapter boards costs pennies, are easy to solder, and let me use the exact chip that I’m going to use in the production boards on my breadboards. I’m going to keep doing that.
You’re free to use DIP chips if that’s what you want to do.
I’m trying to make it clear to people who might be intimidated by modern SMD chips that there are options that will let them use chips that they could otherwise not use, like the ATMEGA328PB or LGT8F328P which only come in TQFP of the ATTINY 1612 which only comes in SOIC-14, while still using their breadboards and Dupont wires.
There is no right option, only the options that’s right for me, and the option that’s right for you.
Do you really need to match the exact chip? I think in practice, sharing across the family is good enough.
Lets focus on two formats. I’m sure you know AVR DD has the 28-pin PDIP that we’ve talked about before. But the 20-pin VQFN (3mm x 3mm) is perhaps what you’re not familiar with. Its electrically compatible with the 28-pin PDIP (just 20-pins instead) and shares the data-sheet / features and everything (same RAM, same assembly, same datasheets and properties).
So my overall argument is that the 28-pin PDIP should be a fine-enough prototype for a 20-pin VQFN final product. Maybe with an intermediate prototype with a 20-pin SOIC (SOIC is a good deal easier to solder after all) if you wanted something that matched pin-for-pin that didn’t require quite the same level of difficulty to solder.
Note that the 20-pin VQFN AVR32DD20 (https://www.digikey.com/en/products/detail/microchip-technology/AVR32DD20-I-REB/16643834) is at that $1 mark, sure a bit more expensive than ATTiny4 but if its space you’re concerned about, the VQFN package at 3mm x 3mm is damn near the 2.8mm x 2.9mm of the SOT-23 6-pin. Aside from the pain in the ass it is to work with leadless (though doable on hobby budgets with a hot-air gun, pancake griddle and solder paste), its not like these small 3mm x 3mm packages are outside of our reach!
With knowledge that modern Microchip chips offer VQFN-20 chips in the 3mm x 3mm footprint, it does feel like SOT-23 6 packages like the ATTiny4 are kind of obsolete. After all, might as well shove 20-pins into that space with today’s level of miniaturization.
I guess the ATTiny4 is cheaper though (under 50-cents in bulk). But the variety of packages offered here by Microchip is basically just for prototyping. SOIC-14, TQFP-32, PDIP-28, SSOP-28… these are all far larger than the VQFN-20 (3mm x 3mm) and VQFN-32 (5mm x 5mm) footprints that would go into a final productized design.
This seems really important to you. It isn’t to me.
I am not going to go back to buying DIP packages of chips. These little adapter boards costs pennies, are easy to solder, and let me use the exact chip that I’m going to use in the production boards on my breadboards. I’m going to keep doing that.
You’re free to use DIP chips if that’s what you want to do.
I’m trying to make it clear to people who might be intimidated by modern SMD chips that there are options that will let them use chips that they could otherwise not use, like the ATMEGA328PB or LGT8F328P which only come in TQFP of the ATTINY 1612 which only comes in SOIC-14, while still using their breadboards and Dupont wires.
There is no right option, only the options that’s right for me, and the option that’s right for you.