| Roushon |
| for op-amps in audio circuits is direct soldering better than using ic base? |
|
|
| ashok |
IMHO ....yes.
However if you want to test different chips you will obviously need one. When you say audio chips I guess you mean circuitry for audio use. That might use very wideband chips which might need to be tamed if mounted on a socket. You will find that many chips for audio use are extremely wideband - seemingly unnecessary but audibly proved otherwise.
Used carefully , you can get by with (machined) sockets.
There are some pictures on some other thread. Do a search.
Cheers. |
|
|
| Markje |
If you use a good socket it is not a problem (in my opinion).
edit: by that I mean, no difference.
Greetz Mark |
|
|
| peranders |
The only reason for using a IC socket is if you want to replace the IC in a easy way, for test purposes etc but normally avoid it!
If you do want to use a socket for some reason, use a socket of good quality with round holes with "tulip" contacts.
Good socket below. |
|
|
| peranders |
| Not so good but cheaper. |
|
|
| ajju |
| If your soldering skill are not that sharp and u fear damaging the component or if its some real sensitive one...going the socket way is a good option initially...!! |
|
|
| jackinnj |
you can get very high quality machined headers -- these come in rows of 25 -- just snip what you need
when I am using DIP ADC's or DAC's I use a socket in the protos -- but there is quite a bit of capacitance and inductance in a "leaded" device vs an SMT device. |
|
|
| ajju |
| yes...the stray elements are something to worry about at high frequencies...Especially if ur doing radio work or clocking above 30-50Mhz digital, sockets are a strict no no..!! |
|
|
| jackinnj |
| you don't socket a high speed current feedback amplifier... |
|
|
| ajju |
| Any high speed device(or high bandwidth device) operated at full or near full bandwidths or high gains might suffer from parasitics if not adequetly taken care off...!! Lead inductances, inter-lead coupling capacitances etc shows pronounced indulgance especially at high frequencies. |
|
|
| gmphadte |
U can use a socket for specific reasons as all have mentioned, but after u have done the final decision, solder it. U will have tarnished metal (even on gold plated) within some days, due to the weather in my/ur part of India and u will have associated problems.
Also that a soldered IC is heatsinked (sort of)
Gajanan Phadte |
|
|
| digi01 |
| ;) another one,i think it is more easy to rolling the chips. |
|
|
| peranders |
digi, the price tag of such :bigeyes: and it's big :nod:
Such socket is only practical for a progamming device and when it is about 100's or 1000's of insertions. |
|
|
| Roushon |
i really appreciate all of your suggestions to my question.
my problem was that i am a bit hesitant to solder directlly an expensive ic like opa627. i am afraid that i can damage it. i need to purchase some good soldering station for this. i will also see if i can find the round holed socket in mumbai. but for ad8620 i have no choice but soldering; it is surface mount type.
thanks. |
|
|
| Markje |
Then use a socket... easy. If you're afraid you damage it, don't solder directly.
Greetz Mark |
|
|
| carlmart |
| quote: | Originally posted by Roushon
but for ad8620 i have no choice but soldering; it is surface mount type.
|
That will be your test. If you can solder a surface mount IC and not damage it, you are certainly able to solder any other IC.
Use a 30W solder base and thin wire solder. Soldering an IC is very fast, just twist at least three pins so the chip will not move while you solder.
Carlos |
|
|
| jackinnj |
for something like the AD8620 I would suggest putting a small dab of solder on one of the PCB tabs (not a glob, a dab -- does that translate ?) tack one end of the chip on this pad -- the rest is easy.
for SMT I use a 7 watt Weller Pencil or the Hakko -- solder paste from Kester works very well -- apply with a needle or very fine tweezers. |
|
|
| carlmart |
| quote: | Originally posted by jackinnj
for SMT I use a 7 watt Weller Pencil or the Hakko -- solder paste from Kester works very well -- apply with a needle or very fine tweezers. |
What temperature you set on the Hakko? I have a 936, but never soldered SMDs yet.
Why do you want solder paste? Don't modern solders have its own?
Carlos |
|
|
| jackinnj |
| quote: | Originally posted by carlmart
Why do you want solder paste? Don't modern solders have its own?
Carlos |
with the Hakko I use the needle tip - fits in between the pins of an SOIC device.
the Kester "solder paste" I use is actually small balls (tiny) of solder suspended in an emulsion -- the consistency of 5-minute epoxy -- as soon as it is touched by the iron it melts.
for those who were wondering, the only small balls in this household are those in the Kester solder. |
|
|
| gmphadte |
| quote: | | my problem was that i am a bit hesitant to solder directlly an expensive ic like opa627. I am afraid... |
Remember soldering is best done with all four touching each other
1 Iron tip 2.solder Lead 3.component pin and 4. PCB pad
No flux necessary since it is present in the solder
If you are going to fix this IC on a socket, then u will NOT get it to work what it is worth. I know U are not going to believe me now.
If u are not confident of soldring it, then I suggest u follow as below
1)Clean all the PCB pads that the IC goes into. (should be shiny)
2)Solder the pads on the PCB,
and then clean and clear the holes.
Insert the IC and solder it with clean and solder wetted iron tip
If u are afraid of damaging the IC due to static, it is IMPOSSIBLE with such high humidity(80%+). Only care that has to be taken is that u use less wattage soldering iron and follow the above method. U will not fail.
The soldering irons like weller(costs thousands) with iron coated tips are difficult to solder with since the tip does not get wetted easily.
As for the SMD IC, it is much easier with a cheap iron like TONY but the bit should be of chisel shape. If it is not, then file it to make like one(3-4 mm chisel). Don't worry it's just copper with coating for cosmetic purpose.
Now follow 1 and 2 above.
Next get rid of the globs and make them dabs by using a solder wick.
Don't have solder wick, then use your imagination.
After this, place the IC properly and glue it at the bottom using small drop of rubber based glue(quickfix, fevibond), in the middle, bottom of the IC.
Now solder as follows
Wet the iron tip (with solder This applies to all above wetting)
Now place the iron tip on the multiple pins. This will solder the pins below and after a second or so move the iron away from the IC but still touching the pins. This will take away the excess solder.
Repeat for all the pins.
After soldering the IC if u find a bridge between the pins, use solder wick or imagination to correct.
Inspect the job with a lens and move a sharp knife between all the pins to get rid of any invisible solder.
Remember, u don't need a good soldering iron but skill and say u are going to get it
Best of luck
Gajanan Phadte |
|
|
| carlmart |
Excellent instructions! Anyone can follow them and do a great job on any parts soldering.
What temperature do you set your solder pen to? I normally use 400 degrees C on my Hakko, but it might be less for SMD.
Carlos |
|
|
| peranders |
| I would recommend 300-370 deg C. I usually use 300 deg. The only time I turn up the temp is when I solder TO220 SMD and similar. |
|
|
| jackinnj |
| I use 370 on the Hakko -- when I have to solder TO-220 I change the tip. |
|
|
| Roushon |
| quote: | Originally posted by gmphadte
Remember soldering is best done with all four touching each other
1 Iron tip 2.solder Lead 3.component pin and 4. PCB pad
No flux necessary since it is present in the solder
If you are going to fix this IC on a socket, then u will NOT get it to work what it is worth. I know U are not going to believe me now.
If u are not confident of soldring it, then I suggest u follow as below
1)Clean all the PCB pads that the IC goes into. (should be shiny)
2)Solder the pads on the PCB,
and then clean and clear the holes.
Insert the IC and solder it with clean and solder wetted iron tip
If u are afraid of damaging the IC due to static, it is IMPOSSIBLE with such high humidity(80%+). Only care that has to be taken is that u use less wattage soldering iron and follow the above method. U will not fail.
The soldering irons like weller(costs thousands) with iron coated tips are difficult to solder with since the tip does not get wetted easily.
As for the SMD IC, it is much easier with a cheap iron like TONY but the bit should be of chisel shape. If it is not, then file it to make like one(3-4 mm chisel). Don't worry it's just copper with coating for cosmetic purpose.
Now follow 1 and 2 above.
Next get rid of the globs and make them dabs by using a solder wick.
Don't have solder wick, then use your imagination.
After this, place the IC properly and glue it at the bottom using small drop of rubber based glue(quickfix, fevibond), in the middle, bottom of the IC.
Now solder as follows
Wet the iron tip (with solder This applies to all above wetting)
Now place the iron tip on the multiple pins. This will solder the pins below and after a second or so move the iron away from the IC but still touching the pins. This will take away the excess solder.
Repeat for all the pins.
After soldering the IC if u find a bridge between the pins, use solder wick or imagination to correct.
Inspect the job with a lens and move a sharp knife between all the pins to get rid of any invisible solder.
Remember, u don't need a good soldering iron but skill and say u are going to get it
Best of luck
Gajanan Phadte |
Hi Gajanan,
It is a very very practical way of explaning your simple solution to the question I asked.
In fact I have a 10W and a 25W TONY soldering irons. And I used them before almost exactly the way you described. I have soldered TTL, CMOS ICs direclty without damaging them. I have filed the bits to suit it for some fine soldering. But my feeling was that a audio circuit is different and needs more care (as reproduction of sound is a difficult job). And this is the first time I am into some serious audio circuit. Yes the humidity here is very high as you know, so static problem is not there. Now it gives me confidence that I can go ahead using my old tricks and solder SMD etc....
With best regards... |
|
|
| gmphadte |
This is for those who read quick.
The iron tip of these expensive irons is not to be filed.
Gajanan Phadte |
|
|
| gmarsh |
| quote: | Originally posted by gmphadte
This is for those who read quick.
The iron tip of these expensive irons is not to be filed.
Gajanan Phadte |
I'm not sure what metal my 936 uses, but you can file them. I've resurrected a couple of tips at work.
I converted one of my Hakko tips to a miniwave tip with a Dremel. It tinned up and works wonderfully for soldering surface mount stuff. I'll probably take a picture of it later... |
|
|
| gmphadte |
no idea, but in such cases and if your iron tips are costly, try making one from copper rod. Some tip coatings are for increasing life of the tip. Only one I know was a Weller soldering station with iron coating and the tip was used for 15 years, after which the sensing component gave up.
Now at work, we don't need to use a soldering iron very often since we only replace cards.
Gajanan Phadte |
|
|
|
