Hi all,
I am planning my first DAC project. As nearly all DAC devices are in SSOP package, the soldering temperature and duration that are mentioned in the datasheet will affect the final quality of the DAC. I do not have any sophisticated instrument to work on it. Could anyone tell me how to solder SSOP ICs? or you can share your experience on soldering it? Thanks.
I am planning my first DAC project. As nearly all DAC devices are in SSOP package, the soldering temperature and duration that are mentioned in the datasheet will affect the final quality of the DAC. I do not have any sophisticated instrument to work on it. Could anyone tell me how to solder SSOP ICs? or you can share your experience on soldering it? Thanks.
Just use a soldering iron with a very small tip and plain 60/40 tin diam. 0.7 mm and a steady hand.
I use this iron. Weller WS-81
You don't have to think about temperature and time. 270 deg C for 3-5 seconds is OK.
I use this iron. Weller WS-81
An externally hosted image should be here but it was not working when we last tested it.
You don't have to think about temperature and time. 270 deg C for 3-5 seconds is OK.
the very first smd package I soldered was a SSOP28.
I firmly put the chip on the pads, put a lot of solder on my soldering iron (with a rather wide tip) and slowly passed over the pins. I then let it cool down. Then I just put some desoldering braid on the pins and passed the soldering iron on it. No bridges, no free pins. Perfect result
I firmly put the chip on the pads, put a lot of solder on my soldering iron (with a rather wide tip) and slowly passed over the pins. I then let it cool down. Then I just put some desoldering braid on the pins and passed the soldering iron on it. No bridges, no free pins. Perfect result
Your method is brutal but works also but you mustn't hesitate, then you will have tin between the pins.
Here's something I wrote a bit ago. It is very basic, but assumes almost nothing. JG
Hand Soldering Surface Mount ICs
John Guy, August 4, 2004
In the mid 1980s, the electronics industry began an almost unilateral move towards using surface mount technology. Surface mount technology (SMT) packaging offers many advantages over through-hole components, including smaller size, lower profile, lower cost, and higher performance. About the only area where SMT does not beat through-hole technology is in prototyping. Hand soldering SMT devices can be a daunting task for those without direct experience. This note serves as a starting point for those who wish to learn to hand solder SMT devices.
This note assumes you have an existing PCB or other suitable board to attach the SMT device. If you need help in this area try Prototyping with Surface Mount ICs
http://www.maxim-ic.com/appnotes.cfm/appnote_number/1110
an application note detailing one method for generating a suitable circuit board.
Almost all SMT devices will work with whatever solder you have on hand. This is based on the solder I’ve worked with, which has always been an alloy of tin and lead. Most of these are based on about 63% tin and 37% lead, the eutectic mixture ratio for tin and lead. As with any material containing lead, you should consult the MSDS from your solder’s manufacturer for safe handling guidelines. Expect in the near future the electronics industry will be using substitutes for tin/lead solder in many or all applications.
Whatever solder is selected; it needs a flux to ensure proper adhesion, or wetting, of the materials being soldered. Most standard lab solders have an intrinsic flux core. One of the standards here is rosin, a natural derivative of pine tree sap. Other fluxes are engineered to provide special properties. In most situations a rosin core solder is an excellent product. Soldering SMT devices is easiest with smaller gauges of solder.
The best soldering iron for use with SMT devices is an iron specifically designed for SMT devices. These feature narrower tips optimized to provide precise heat to a small area. If you have an SMT-specific soldering iron, it will make hand soldering much easier. If you have a general-purpose soldering iron you still may be able to work with it depending on the thickness of the tip, the lead pitch of the SMT IC, the steadiness of your hand, and your quantity of patience. Specific techniques will be discussed later in this note.
Another highly useful tool is a stereo inspection microscope. This is not absolutely necessary, especially for the wider lead-pitch devices. In fact, most people who solder SMT devices by hand do not have a microscope, yet they achieve excellent success rates. In lieu of a microscope, a jeweler’s loupe or a magnifying glass can help with verification of the soldering job. Again, many people have no problems assembling SMT boards without vision enhancing devices.
The first step in hand-soldering an SMT device is to verify the pin 1 orientation of the device. This is usually found on the IC datasheet, or sometimes on the IC manufacturer’s website under packaging information. Take the soldering iron and a piece of thin gauge solder and place a small dab of solder on one of the corner pins of the PCB land pattern. Align the IC to the land pattern with the correct pin 1 orientation. While holding the IC with a pair of tweezers, touch the soldering iron to the one pad previously soldered. Remove the iron, wait a few seconds, then release the tweezers. At this point visually inspect to verify the IC is correctly aligned to its PCB land pattern. If it is not properly aligned, reapply the soldering iron to the one pin, and adjust the IC’s location with the tweezers. Repeat this process until the IC is satisfactorily aligned. After the first pin is soldered and the alignment verified, solder the pin on the opposite corner of the IC. Then proceed down each side of the IC to solder each pin to its respective land.
If your soldering iron is too large to solder individual pins, simply solder them down to the PCB as a single unit. Then, come back to the pins with the soldering iron and a fresh piece of solder wick. Solder wick is a fine braid of bare copper, specifically intended to wick up excess solder from PCBs. In this case, you’ll find the solder wick removes the excess solder shorting adjacent pins, leaving cleanly soldered and electrically sound solder joints. Solder wick is also useful for fixing errors even if you have an SMT-specific soldering iron.
Hand-soldering SMT devices is not rocket science, but it does take some practice to become proficient. It’s best to start with ICs and boards which are not critical and practice. Once learned, you’ll find yourself opened up to using the many state-of-the-art ICs which are available exclusively in SMT packages.
Hand Soldering Surface Mount ICs
John Guy, August 4, 2004
In the mid 1980s, the electronics industry began an almost unilateral move towards using surface mount technology. Surface mount technology (SMT) packaging offers many advantages over through-hole components, including smaller size, lower profile, lower cost, and higher performance. About the only area where SMT does not beat through-hole technology is in prototyping. Hand soldering SMT devices can be a daunting task for those without direct experience. This note serves as a starting point for those who wish to learn to hand solder SMT devices.
This note assumes you have an existing PCB or other suitable board to attach the SMT device. If you need help in this area try Prototyping with Surface Mount ICs
http://www.maxim-ic.com/appnotes.cfm/appnote_number/1110
an application note detailing one method for generating a suitable circuit board.
Almost all SMT devices will work with whatever solder you have on hand. This is based on the solder I’ve worked with, which has always been an alloy of tin and lead. Most of these are based on about 63% tin and 37% lead, the eutectic mixture ratio for tin and lead. As with any material containing lead, you should consult the MSDS from your solder’s manufacturer for safe handling guidelines. Expect in the near future the electronics industry will be using substitutes for tin/lead solder in many or all applications.
Whatever solder is selected; it needs a flux to ensure proper adhesion, or wetting, of the materials being soldered. Most standard lab solders have an intrinsic flux core. One of the standards here is rosin, a natural derivative of pine tree sap. Other fluxes are engineered to provide special properties. In most situations a rosin core solder is an excellent product. Soldering SMT devices is easiest with smaller gauges of solder.
The best soldering iron for use with SMT devices is an iron specifically designed for SMT devices. These feature narrower tips optimized to provide precise heat to a small area. If you have an SMT-specific soldering iron, it will make hand soldering much easier. If you have a general-purpose soldering iron you still may be able to work with it depending on the thickness of the tip, the lead pitch of the SMT IC, the steadiness of your hand, and your quantity of patience. Specific techniques will be discussed later in this note.
Another highly useful tool is a stereo inspection microscope. This is not absolutely necessary, especially for the wider lead-pitch devices. In fact, most people who solder SMT devices by hand do not have a microscope, yet they achieve excellent success rates. In lieu of a microscope, a jeweler’s loupe or a magnifying glass can help with verification of the soldering job. Again, many people have no problems assembling SMT boards without vision enhancing devices.
The first step in hand-soldering an SMT device is to verify the pin 1 orientation of the device. This is usually found on the IC datasheet, or sometimes on the IC manufacturer’s website under packaging information. Take the soldering iron and a piece of thin gauge solder and place a small dab of solder on one of the corner pins of the PCB land pattern. Align the IC to the land pattern with the correct pin 1 orientation. While holding the IC with a pair of tweezers, touch the soldering iron to the one pad previously soldered. Remove the iron, wait a few seconds, then release the tweezers. At this point visually inspect to verify the IC is correctly aligned to its PCB land pattern. If it is not properly aligned, reapply the soldering iron to the one pin, and adjust the IC’s location with the tweezers. Repeat this process until the IC is satisfactorily aligned. After the first pin is soldered and the alignment verified, solder the pin on the opposite corner of the IC. Then proceed down each side of the IC to solder each pin to its respective land.
If your soldering iron is too large to solder individual pins, simply solder them down to the PCB as a single unit. Then, come back to the pins with the soldering iron and a fresh piece of solder wick. Solder wick is a fine braid of bare copper, specifically intended to wick up excess solder from PCBs. In this case, you’ll find the solder wick removes the excess solder shorting adjacent pins, leaving cleanly soldered and electrically sound solder joints. Solder wick is also useful for fixing errors even if you have an SMT-specific soldering iron.
Hand-soldering SMT devices is not rocket science, but it does take some practice to become proficient. It’s best to start with ICs and boards which are not critical and practice. Once learned, you’ll find yourself opened up to using the many state-of-the-art ICs which are available exclusively in SMT packages.
I find it rather easy... I:
Coat the PCB's IC pads in flux.
Tin the PCB's IC pads.
Remove any excess solder with braid (but not all of it).
Apply more flux to the pads.
Place the IC.
With a super clean soldering tip (doesnt have to be small), apply heat to all pins.
On applying heat, youll see the IC pins take up the solder from the tinned pad.
Easy.
Coat the PCB's IC pads in flux.
Tin the PCB's IC pads.
Remove any excess solder with braid (but not all of it).
Apply more flux to the pads.
Place the IC.
With a super clean soldering tip (doesnt have to be small), apply heat to all pins.
On applying heat, youll see the IC pins take up the solder from the tinned pad.
Easy.
Thank for sharing your invaluable knowledge.
Two approaches can be used to solder those tinny surface mount devices. 1, Solder the IC first and then remove the excess solder with the help of braid. 2, Coat the IC pads with solder and then mount the IC on it. Let me practise more. Thank all.
Two approaches can be used to solder those tinny surface mount devices. 1, Solder the IC first and then remove the excess solder with the help of braid. 2, Coat the IC pads with solder and then mount the IC on it. Let me practise more. Thank all.
I got a tutorial for the crude method: http://members.lycos.nl/anthonyvh/index.php?page=smd (seems to be down due to maintaince for the moment though)
The easiest way is to use solder paste plus a hot air gun. Please check out this:
http://www.usbmicro.com/odn/documents/46.html
The hot air pencil described at the beginning of the page is a good/cheap tool. Solder paste is not hard to get either.
Sometimes I use Weller's WSD80 with a SMD tip. It works out great.
http://www.usbmicro.com/odn/documents/46.html
The hot air pencil described at the beginning of the page is a good/cheap tool. Solder paste is not hard to get either.
Sometimes I use Weller's WSD80 with a SMD tip. It works out great.
finneybear said:
The toaster oven is working fine, mostly I use 1206 type parts which are easier than 0805, sometimes 0603.
I place a tiny dab of solder paste on each of the PCB pads, mount all the passive devices, then cook in the oven -- after heating I check all connections with a continuity tester and/or ohm-meter. The IC's I usually solder by hand.
My PCB technique is to place everything possible on the top of the board, including the traces. If I have to use a big polyester cap in the signal path I mount them on the bottom so they can be soldered upside down.
It is helplful to have a variety of small knives, utility knife blades etc.
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