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Topic: Why are DIPs so inneficient compared to SMDs? (Read 2 times) previous topic - next topic

Graynomad

@westfw
I remember the 68000 in the 64-pin pack, we used to call that package an "aircraft carrier pack".  :)
Rob Gray aka the GRAYnomad www.robgray.com

cr0sh

Quote
I remember the 68000 in the 64-pin pack, we used to call that package an "aircraft carrier pack".


There was never a problem finding the CPU in the Amiga...!
I will not respond to Arduino help PM's from random forum users; if you have such a question, start a new topic thread.

Christopher Singleton

As someone has already suggested . . . hold onto your DIPs while you can because the time that they will start disappearing is now.

Most of my electronic hobby work centre's around science based instrumentation (seismographs, mircobarographs, monitoring the Aurora Borealis or electrical storms). While there are a lot of pre-existing schematics for these kinds of projects, most of them are more than 10 years old and consequently many of the IC's, transistors and misc discrete components are obsolete. If you are lucky, then they might be available in SMD as a sample . . . however, in many cases you are just SOL.

That's where the Arduino comes in!

My current project is a microbarograph which is an instrument that monitors infrasonic (sound waves far below normal hearing range) energy.

The circuit involves a simple heater control that turns on when triggered by a low level sensor monitoring of opaque liquid in a manometer (bent u-shaped glass tube). The second part of the circuit is a simple instrumentation amplifier that monitors the actual temperature fluctuation that triggers the heater circuit. These temperature fluctuations form the devices output that can be data logged.

Several of the required components are extremely difficult to find, but the functions of both circuits are relatively easy to accomplish with an Arduino and some relatively easy programming.

Without the Arduino, some of these circuits would require re-engineering by someone a lot more knowledgeable than me.

electrosys

How they solder this leadless chips on the PCB circuit?! The "leads"
are under the chip! I know there is some kind of robotic system that
doing the job, but I very much like to see how they do it!


Grumpy_Mike

#19
Jun 11, 2010, 12:57 am Last Edit: Jun 11, 2010, 12:58 am by Grumpy_Mike Reason: 1
Who are "they"?

The correct way to wire that up is to use a PCB with solder paste on the tracks. You put the chip on top of the solder paste and place it on an oven so that the solder paste melts.

You can do it by hand by just applying a soldering iron to the PCB track, apply a little solder and capalary action sucks the solder under the chip.

Finally there is the dead bug method. Turn the chip on it's back and glue it down. Then solder fine wires to the connections.

westfw

#20
Jun 11, 2010, 03:36 am Last Edit: Jun 11, 2010, 03:37 am by westfw Reason: 1
I can hardly wait till all chips look like this:

It's just SO much more space efficient.  And the fact that they'll require 6-layer professionally made PCBs and professional automatic assembly will help keep away those darned hobbyists who are always trying to build that weird stuff!

(this is the I found quickest to photograph.  The serious modern chips have that array of solder balls covering the entire bottom of the chip.  1000+ connections...)

Tim Sullivan


Grumpy_Mike

Hi westfw,
I didn't know Americans could do irony, well done.  ;)

Bob H

My company buys millions of micro-controllers per year, paying for excess packaging is excess expense and no one wants that, especially not the consumer who buys the end product.  8-)

In addition every through-hole component added to a PCB under automation makes the product less reliable because of the vibration that passes through the board with the force of the component insertion process. In contrast SMT is gently rolled through on a conveyor and heated, poor placement and production can automatically be tested with an automatic microscope.

pwillard

#24
Jun 15, 2010, 02:29 am Last Edit: Jun 15, 2010, 02:32 am by pwillard Reason: 1
Standard DIP's are still made... for convenience only.

DIP packaging (as stated earlier) was developed in the late 60's.  I actually worked as a through-hole Wave Solder machine operator in the 1970's and know that in many cases.. DIP chips (and other components) were hand inserted unless you were a BIG company and could afford the robotic stuffers.

The Benefit of DIPS was clear... they were tough and easily hand inserted.  Could be easily and cheaply socketed and went directly from R&D to Manufacturing.  Micro-miniature cases  (similar to SMD's) were created... but they were seldom justified when designs were for standard TTL data systems... (IE Honking Big Computers) which were all the rage in the 70's and 80's.


The reason for the SIZE is simple.  You need a certain SIZE pin to withstand insertion force.  Anything smaller and you destroy the device if inserting into a 70's era socket.

The design of the internal contents of the DIP are important... that wasted space you imagine is actually where the pins run... all to the center of the package.  The pins on DIPS are created by STAMP CUTTING from a singe flat sheet of metal.  The pins are radially cut and really do need to use all the space so the 0.100 spacing can be maintained.

DIP INFO
http://en.wikipedia.org/wiki/Dual_in-line_package



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