srnet
August 9, 2018, 9:13am
1
I am working on a project that will use a ATmega 1284P in its 44 pin QFN package.
There are plenty of instructions\videos to be found showing how to DIY solder them to boards and I have used some smaller QFNs in the past.
The PCBs will be small and low cost, around 10p each, so I dont mind wasting a few practicing.
The 1284ps are £5 each, I would rather not waste them.
So can I get dummy packages to try my DIY SMT skills on ?
MarkT
August 9, 2018, 9:43am
2
No, but there are much cheaper chips in QFN.
[ Having said that some counterfeit electronics are empty packages... ]
pert
August 9, 2018, 11:47am
3
Cheapest I could find are the ATmega324P (or maybe ATmega164P). Not super cheap but it's nice that the chip is actually useful for something.
srnet
August 9, 2018, 12:01pm
4
Unfortunately a 32pin QFN does not fit on the 44pin PSB pads for the 1284P.
LarryD
August 9, 2018, 12:02pm
5
Suggest you use TQFP rather than QFN
QFN can be a bit difficult.
pert
August 9, 2018, 12:12pm
6
srnet:
Unfortunately a 32pin QFN does not fit on the 44pin PSB pads for the 1284P.
Who said anything about a 32 pin QFN? If you're responding to my suggestion of ATmega324P, it uses the 44pin QFN 7x7 package just like the ATmega1284P. It's in the same family. Same IO, pin compatible, but with less memory. Same with the ATmega164 but those are actually a little more expensive on Digikey than the ATmega324.
srnet
August 9, 2018, 12:19pm
7
pert:
If you're responding to my suggestion of ATmega324P
Apologies, I actually checked the 328P datasheet ................
Farnell have them, about £1.60.
srnet:
I am working on a project that will use a ATmega 1284P in its 44 pin QFN package.
There are plenty of instructions\videos to be found showing how to DIY solder them to boards and I have used some smaller QFNs in the past.
The PCBs will be small and low cost, around 10p each, so I dont mind wasting a few practicing.
The 1284ps are £5 each, I would rather not waste them.
So can I get dummy packages to try my DIY SMT skills on ?
Google has a bunch of links if you look for "dummy smd devices"
Paul
srnet
August 9, 2018, 6:55pm
9
Paul_KD7HB:
Google has a bunch of links if you look for "dummy smd devices"
Paul
Yep, and one supplier in the UK. Minimum order Q of £50.
Somewhere, no doubt in China, I bet they a landfill site full of 'rejects'
MarkT
August 9, 2018, 9:13pm
10
pert:
Cheapest I could find are the ATmega324P (or maybe ATmega164P). Not super cheap but it's nice that the chip is actually useful for something.
No, there are many much cheaper QFN devices, smaller devices, everyone's phones are full of them.
For instance voltage regulators.
pert
August 9, 2018, 9:29pm
11
Care to suggest one? I searched all the voltage regulator categories on Digikey and the cheapest part in 44-QFN (7x7) package is $4.94, but with a 2000 piece minimum order quantity. The cheapest available in single piece quantity is $10.62:
srnet
August 9, 2018, 10:31pm
12
MarkT:
No, there are many much cheaper QFN devices, smaller devices, everyone's phones are full of them.
For instance voltage regulators.
Are there ?
How many do you have to buy ?
MarkT
August 10, 2018, 9:43am
13
srnet:
Are there ?
How many do you have to buy ?
Price breaks and postage costs depend on your electronics supplier... And there seem to be a good choice
of QFN and DFN opamps from a low price up too.
pert
August 10, 2018, 10:16am
14
Not a single 44-QFN package Op Amp listed on Digikey. Please provide a part number.