TQFP 80 18F8720 adapter

[nilsener]

Dear,

we want to use 18F8720 for our new design but we ask us how to replace the chip if it fails during the software development. Does someone know where to buy a TQFP 80 to TQFP 80 adapter that can be soldered onto the smd pads and then plug in the TQFP 80 Device ?

Thanks for helping

best regards
nilsener
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This message was ported from CCS's old forum
Original Post ID: 144515471

[john cutler]

I don't know if they make one with that many pins, but I know it will cost a lot more than a $40 CCS board.

JC
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This message was ported from CCS's old forum
Original Post ID: 144515476

[john cutler]

You might try these guys...I spoke to them and they are very helpful - they will even let you send them a few chips and they'll mount them to their adapters, which is what I need - I'm still in dip land.

jc
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This message was ported from CCS's old forum
Original Post ID: 144515477

[Douglas Kennedy]

This chip may have been destined to come out in a PLCC84 package. In fact Microchips picstart notes for this chip referenced a plcc84 pinout instead of the 80qfp. It maybe another case of Microchip marketing interfering with engineering development.We are lucky the 8720 wasn't a circular chip to match the ICD2 hockey puck concept.
I drew up a circuit to take the pins out to a square of four 2x20 .1" pins ....sent it to www.expresspcb.com and for $62 got back six headers. On my breadboard or target board I have the square( 4 sides ) 2x20 IDC type sockets to receive the header board. I find I really need to be able to unplug these pesky chips. They are much more prone to fail than their sturdier DIP cousins. A crossed trace or just about any mistake and a 18F8720 is toast. Microchip really should have come out with a robust package for developers
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This message was ported from CCS's old forum
Original Post ID: 144515479

[john cutler]

I just don't see well enough (or have a steady enough hand) to solder things that small! Nor do I have the $$$ for a microcope, special irons, hot air etc.
Am I to becme obsolete because of miniaturization? I always thought it wold be Azheimers
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This message was ported from CCS's old forum
Original Post ID: 144515482

[Douglas Kennedy]

:=I just don't see well enough (or have a steady enough hand) to solder things that small! Nor do I have the $$$ for a microcope, special irons, hot air etc.
:=Am I to becme obsolete because of miniaturization? I always thought it wold be Azheimers <img src="http://www.ccsinfo.com/pix/forum/smile.gif" border="0">

Sadly since Microchip doesn't want to help us much , many will just avoid developing for this chip.

Since I needed the extra program ROM space here is what I did.
without using a hot air rework station.
Position the pesky chip and gingerly tack solder a pin at each corner. (This keeps it from moving when placing it in the toaster oven... and yes you will need magnifying glasses)
Mark the pcb with a color changing wax pen or cut a small piece of solder wire and place on a truhole. Place board and chip in an old toaster oven and wait for the color to change ( or the small piece of solder wire to melt) indicating the solder has melted under the 8720 chip pins and reflowed
turn off the toaster oven and let the board cool down
Now so no one risks getting lead poisoning don't use the oven for toast or anything else.
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This message was ported from CCS's old forum
Original Post ID: 144515486

[John Yaron]

:=Dear,
:=
:=we want to use 18F8720 for our new design but we ask us how to replace the chip if it fails during the software development. Does someone know where to buy a TQFP 80 to TQFP 80 adapter that can be soldered onto the smd pads and then plug in the TQFP 80 Device ?
:=
:=Thanks for helping
:=
:=best regards
:=nilsener

I was unable to find a socket.
The best I came up with is pricy consisting of:

PACE MBT250 rework station
PACE Pik & Paste 100

of course, microscope required also.. picked up a
MicroMaster on EBAY for $500

But, laying down a bead of solder paste, placing
the chip in it and hot air jet reflowing it
gives superior results and is quite easy once
you get the hang of it.... so much to the point
that I don't even do thru-hole anymore...even
on my in-house test and programming boards

Arm/Elbow rests are achieved my putting the scope
in the recessed knee of 2 table's at 90 degree angles

I've built some protoypes that look just like a
production board.
0.5mm pitch 18F8720's are even becoming
ho-hum to install/remove anymore.

The only trick is keeping the discrete/chip from moving
due to the hot air flow/pressure, but, the variable
flow valve solves that.


Like you say... I don't want to obsolete myself, so,
I figure ...pay the piper
It's worth it in the long run.
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This message was ported from CCS's old forum
Original Post ID: 144515494

[nilsener]

<font face="Courier New" size=-1>Dear Douglas,

I have searched for the picstart notes on microchips's website but I did not found it. Please can you be so kind to tell me where to find this document ?

Thanks a lot and
best regards
nilsener


:=This chip may have been destined to come out in a PLCC84 package. In fact Microchips picstart notes for this chip referenced a plcc84 pinout instead of the 80qfp. It maybe another case of Microchip marketing interfering with engineering development.We are lucky the 8720 wasn't a circular chip to match the ICD2 hockey puck concept.
:=I drew up a circuit to take the pins out to a square of four 2x20 .1" pins ....sent it to www.expresspcb.com and for $62 got back six headers. On my breadboard or target board I have the square( 4 sides ) 2x20 IDC type sockets to receive the header board. I find I really need to be able to unplug these pesky chips. They are much more prone to fail than their sturdier DIP cousins. A crossed trace or just about any mistake and a 18F8720 is toast. Microchip really should have come out with a robust package for developers</font>
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This message was ported from CCS's old forum
Original Post ID: 144515546

[Douglas Kennedy]

I pointed out to Microchip that the documnetation was wrong wrt to the PLCC84 pinouts for the 18F8720 or they forgot to make that package. The correspondence is in the MICROchip picstart plus forum under 18F8720
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This message was ported from CCS's old forum
Original Post ID: 144515570

[Tony Gruber]

Microchip has an XLT80PT emulator adapter (list $125) that solders to the pads on your board. A custom interface board could be made that carries 18F8720 and has headers that plug onto the emulator adapter. When the chip fails this interface board would unplugged and discarded.

:=Dear,
:=
:=we want to use 18F8720 for our new design but we ask us how to replace the chip if it fails during the software development. Does someone know where to buy a TQFP 80 to TQFP 80 adapter that can be soldered onto the smd pads and then plug in the TQFP 80 Device ?
:=
:=Thanks for helping
:=
:=best regards
:=nilsener
___________________________
This message was ported from CCS's old forum
Original Post ID: 144515577