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Would you want to solder a TQFP IC?

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blueroomelectronics

Well-Known Member
I'm still finalising the Ladybug and there is a wonderful IC from Microchip called a PIC18F67J60 which is an 18F with 128K bytes (64K words) and built in Ethernet. Problem is it's only available in a 64pin TQFP package. I've not soldered such small ICs but it sure would be nice.
 
I just swapped out a 16F877A 44TQFP for an 18F4620 today. It took me 10 minutes and was no problem, and I am slow.

In all fairness, I had a Meiji optical inspection scope, and about 2k of OKi rework equipment at hand. And yes, I still took that long :)
 
blueroomelectronics said:
I'm still finalising the Ladybug and there is a wonderful IC from Microchip called a PIC18F67J60 which is an 18F with 128K bytes (64K words) and built in Ethernet. Problem is it's only available in a 64pin TQFP package. I've not soldered such small ICs but it sure would be nice.
They're a LOT easier to solder than ya think. You have a good quality temp controlled iron with a nice fine tip, I assume? I have a Weller WES50, which works fine.

I soldered every component on this board. 100% surface mount components except the header pins. It all works :D
mavricsm.jpg

The trick is to preflux your board. Then, with a bit of solder on the tip of your iron, "tack" a couple pins on the corners so the chip doesn't skate around. Then just go around it and just touch each pin. You may have to add a bit of solder to some chips.

If you bridge some, don't panic. It's easy to fix. Get out your solder wick and suck up the excess.

The little resistors and capacitors and LEDs are easy too. Same deal with the preflux. Then hold the component down with your fingernail (or an implement if you're shy of burned fingers) and tack one end with a tiny dab of solder on the iron. Then solder the other end.

You need good eyes (I don't have em - I just take glasses off, get close and squint a lot), lots of light, a good iron and a bit of patience. :)
 
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Hmm food for thought, the only SMD part will be the PIC. I may get rid of the LCD as it's the only 5V part remaining and I'll have to find a 3.3V ULN2803.
 
blueroomelectronics said:
Hmm food for thought, the only SMD part will be the PIC. I may get rid of the LCD as it's the only 5V part remaining and I'll have to find a 3.3V ULN2803.
Start using surface mounts and your range of available chips expands too, right? Are they any cheaper?

Anyway, don't be afraid of them. They're not so tough.
 
I'm willing to try, but as a kit it might be a devil. Not everyone has the mad skillz and fine tip iron, flux etc... I've got one of the PICs coming and I'll see if I can stand working with it. Looks so teeny!
 
blueroomelectronics said:
I'm willing to try, but as a kit it might be a devil. Not everyone has the mad skillz and fine tip iron, flux etc... I've got one of the PICs coming and I'll see if I can stand working with it. Looks so teeny!
For absolute newb solderers SMD's probably aren't such a good idea. But for intermediate and up, no problem. It really isn't that difficult. A very good, detailed set of instructions, with some good photos and diagrams is a must though. Helps quell the fear-of-new-things a bit.

The resistors and caps are so tiny that if you sneeze or even breathe hard, they're gone! Have to be a bit careful about that. They come in those tape strip things though, so just don't take them out till ready to use them.
 
Hmm you've given me an idea futz, tell me your thoughts on this.
A standalone ethernet kit header, I'll modifiy it so it can fit a solderless breadboard, (no double row headers)
It'll have the PIC, Ethernet jack, SPI EEPROM, voltage regualtor, ICD connector and an LED or two. Much like this photo. No relays or other fancy stuff. It'll mate to the Ladybug or solderless breadboard.
**broken link removed**
 
blueroomelectronics said:
Hmm you've given me an idea futz, tell me your thoughts on this.
A standalone ethernet kit header, I'll modifiy it so it can fit a solderless breadboard, (no double row headers)
It'll have the PIC, Ethernet jack, SPI EEPROM, voltage regualtor. Much like this photo. No relays or other fancy stuff. It'll mate to the Ladybug or solderless breadboard.
Sounds cool! Doo eet! :D I want one.

EDIT: Another thought! Please give us nice pinned out access to all ports.
 
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blueroomelectronics said:
I'm willing to try, but as a kit it might be a devil. Not everyone has the mad skillz and fine tip iron, flux etc... I've got one of the PICs coming and I'll see if I can stand working with it. Looks so teeny!
Since you already sell kits with preprogrammed PICs you could sell this one with a preprogrammed and premounted PIC for the easily intimidated. The trick would be to find a board house which could do it cheaply.
EDIT: Just saw your other post after I clicked submit. A prebuilt board with headers for a breadboard is the better solution and probably wouldn't cost much more anyway.
 
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Yes yes!, this sounds like a plan. I was worried that some kit builders would shy away from the TQFP. But it could stand on it's own as a kit or assembled, and would still allow for the Ladybug to be a much easier and better kit. (PIC18F67J60 has more memory 128K than the 18F4620 & 2 ESUARTS are better than one)
It'll be narrow enough to fit on a standard breadboard, run on 5-7VDC (own requlator also surface mount) and soldered SOIC EEPROM to keep it small.
I want to name it something with an "E" for Ethernet, or perhaps it could be Ladybug Lan...
 
blueroomelectronics said:
Yes yes!, this sounds like a plan. I was worried that some kit builders would shy away from the TQFP. But it could stand on it's own as a kit or assembled, and would still allow for the Ladybug to be a much easier and better kit. (PIC18F67J60 has more memory 128K than the 18F4620 & 2 ESUARTS are better than one)
It'll be narrow enough to fit on a standard breadboard, run on 5-7VDC (own requlator also surface mount) and soldered SOIC EEPROM to keep it small.
I want to name it something with an "E" for Ethernet, or perhaps it could be Ladybug Lan...

Names:

Elephant
Emu
Eagle
Elk
Eel
earthworm

There yeh go some names :)
 
Cricket comes later, it's designed to connect to the Ladybugs RS485 so you can have an Ethernet based HVAC system.
I'm thinking about embedding the RS485 on the board, still leaves me one ESUART externally.

I like Eagle, I may just call it Ladybug as it's so cute. A blue ladybug :)

Edit only 1 ESUART on the PIC, opps. Still nice wee part nonetheless.
 
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futz said:
They're a LOT easier to solder than ya think. You have a good quality temp controlled iron with a nice fine tip, I assume? I have a Weller WES50, which works fine.

I soldered every component on this board. 100% surface mount components except the header pins. It all works :D
**broken link removed**

The trick is to preflux your board. Then, with a bit of solder on the tip of your iron, "tack" a couple pins on the corners so the chip doesn't skate around. Then just go around it and just touch each pin. You may have to add a bit of solder to some chips.

If you bridge some, don't panic. It's easy to fix. Get out your solder wick and suck up the excess.

The little resistors and capacitors and LEDs are easy too. Same deal with the preflux. Then hold the component down with your fingernail (or an implement if you're shy of burned fingers) and tack one end with a tiny dab of solder on the iron. Then solder the other end.

You need good eyes (I don't have em - I just take glasses off, get close and squint a lot), lots of light, a good iron and a bit of patience. :)

You are super.
Fans just cannot help telling me how much they love the SMD packages after they succeed on our CB0703-PICkit2 DIY units. It looks it would be a harder job than through-hole components, however once you get used to it, you will never go back.

With SMD package, the size is smaller, and the finished DIY kits looks more professional.

There is a young man in Canada bought a CB0703-PICkit2 combo DIY kits for his father as a Christmas gift, who turn out a big electric-DIY-fan but never handle SMD parts before. At first, he almost lost his confidence for the new Christmas gift. With some help from our support and new FAQs on our web site, he accomplished his own PICkit2 and tried one PIC chip he never be able to program with his old programmers, it succeed. He wrote to us, what a miracle!
 
Yep, Futz is correct, it is much easier than it looks.
You need good eyes (I don't have em - I just take glasses off, get close and squint a lot), lots of light, a good iron and a bit of patience.
(Futz, I thought you were younger... BTW, board looks great!)
I use a 'honkin' big magnifier with lamp, and sometimes I use 3x reading glasses, in addition to the magnifier. :p

There are a few places on the net, selling kits, where a TQFP is already mounted, and building the kit involves adding the trough hole parts, I think you could do very well with that.
From what I've seen, Bill, you lay out your boards very well, so you should be able to make a deadly board with this chip! :)
 
I'm just going over the design, it looks like a relativly straight forward kit design.
So it'll have
PIC18F67J60 64pin TQFP
EEPROM 25AA1024 (64k)
3.3V regulator
ICD connector for Junebug, Inchworm or PICkit2
headers that are solderless breadboard compatible for all unused I/O, hoping to limit them to 20pins each (40 total)
Ethernet jack with magentics (supports internal / external LEDs if available)
Heartbeat LED (1 I/O), power LED
Jumpers for the RS485 SN75176 (DIP8) - EUSART or I/O
Hole through parts when possible.

Just add power and you have a standalone embedded web server.
Anything I'm missing?
 
Sounds complete, and what I like is that you try to make the best use of all of the pins, which I know can be difficult. (I have a few Olimex boards, and sadly none of yours, YET,) and think you do much better with your IO than Tristvan.

There is another solution for the TQFP, and I'm wondering if you have seen these:
**broken link removed**

They are using a separate eithernet chip, and have issues with pin use... but the idea is there. They also have a header for expansion, which a relay output, (or other) board plugs into. Just a thought, but if you provided the same modularity, would give your kit some scalability... and you could produce a second, third... add on part.
 
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August Treubig said:
Futurlec makes some QFP to DIP boards for next to nothing. Well the big ones aren't Dip, but they drop to .100 dual pin connectors

https://www.futurlec.com/SMD_Adapters.shtml

:)

At first I though you were pointing to Futurlec for their micro boards. I think these are, for the most part, no good. I have a couple, and they stay in the junk box. They can't be programmed using an ICD2, which is my largest complaint...

The TQFP could be mounted on a separate header board, but I don't think it would look as pro...
On the other hand I do have a couple of 18F8720s mounted this way, with a six pin connector, watch crystal and 3 pin header for resonator, external crystal, four rows of header pins- but can't be used on a breadboard...
 
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