Making PCBs: SMD only or hybrid?

[Daniel Kelly (AKA Jack)]

Hi,

I'm in the process of building some PCBs based around a handful of surface
mount ICs. I don't have much experience soldering SMD components but the
ICs I want are only available as SMDs. So my question is: should I keep the
PCBs exclusively SMD or mix SMD and through-hole components? As I see it,
the pros and cons for an Exclusively SMD design are:

Pros
- Elegant PCB
- Can mount the PCB very close to the base of the container because there
will only be components on one side
- It'll impress my friends!

Cons
- I'm worried about soldering SMDs. Some of those capacitors are damn
small!

Is this about right?

Should I stop worrying about soldering SMD capacitors and resistors?

Thanks,
Jack

 

[exxos]

"Daniel Kelly (AKA Jack)" <d.kellyNOSPAM@NOSPAM.ucl.ac.uk> wrote in message
news:caq5jd$159s$1@uns-a.ucl.ac.uk...

Hi,

I'm in the process of building some PCBs based around a handful of surface
mount ICs. I don't have much experience soldering SMD components but the
ICs I want are only available as SMDs. So my question is: should I keep
the
PCBs exclusively SMD or mix SMD and through-hole components? As I see it,
the pros and cons for an Exclusively SMD design are:

Pros
- Elegant PCB
- Can mount the PCB very close to the base of the container because there
will only be components on one side
- It'll impress my friends!

Cons
- I'm worried about soldering SMDs. Some of those capacitors are damn
small!

Is this about right?

Should I stop worrying about soldering SMD capacitors and resistors?

Thanks,
Jack

I've managed to solder the mirco packages by hand, damn small, around a
quarter of the SOIC SMD sizes. The key is a steady hand and patience, you
can do it, SOIC chips are easy to solder, SMD caps are easy, small stuff
like resistors and didoes are small and hard to hold in place, though if you
get the 1206 packages these aint too bad to solder. You can always mix
normal resitors since they can be mounted on the normal parts side no
problem, most manufactures have normal sized parts on the parts side and
solder a SMD chip on the track side, no problems in doing that. Its
probably easier to just stick to the SMD stuff you actually have to use and
mount everything else on the reverse side, I personally use SMD for all
IC's, caps,resitors,didoes,etc I use normal parts, they are easy to work
with and often cheaper anyways!

HTH,
Chris





>

 

[Tam/WB2TT]

"Daniel Kelly (AKA Jack)" <d.kellyNOSPAM@NOSPAM.ucl.ac.uk> wrote in message
news:caq5jd$159s$1@uns-a.ucl.ac.uk...

Hi,

I'm in the process of building some PCBs based around a handful of surface
mount ICs. I don't have much experience soldering SMD components but the
ICs I want are only available as SMDs. So my question is: should I keep
the
PCBs exclusively SMD or mix SMD and through-hole components? As I see it,
the pros and cons for an Exclusively SMD design are:

Pros
- Elegant PCB
- Can mount the PCB very close to the base of the container because there
will only be components on one side
- It'll impress my friends!

Cons
- I'm worried about soldering SMDs. Some of those capacitors are damn
small!

Is this about right?

Should I stop worrying about soldering SMD capacitors and resistors?

Thanks,
Jack


Jack,

If you are making your own boards, I have two suggestions. First, if at all
possible pick SM IC packages with pitch no smaller than .050. Second, on a
two layer board, through-hole parts are handy to use for crossovers and
feedthroughs. At any rate, I would use the though-hole parts for
transformers and non microwave inductors .

If you go the all SM path, I find that Rs and Cs in 805 and 1206 packages
are a lot easier to handle than the small stuff. Also, the 1206 can easily
be used for a same side crossover.

Tam

 

[CWatters]

"Daniel Kelly (AKA Jack)" <d.kellyNOSPAM@NOSPAM.ucl.ac.uk> wrote in message
news:caq5jd$159s$1@uns-a.ucl.ac.uk...

SMD is easier sometimes! No holes to drill and tracks only on one side
making routing easier on the other.

- I'm worried about soldering SMDs. Some of those capacitors are damn
small!

The trick is to hold the capacitor down with the tip of a small screw driver
or a knife blade. Then solder one end. If that's ok solder the other. If you
don't hold the capacitor down surface tension of the solder causes it to
move around.

Is this about right?

Should I stop worrying about soldering SMD capacitors and resistors?

Yes it's not too bad.

To remove a capacitor apply solder to the iron and run the iron down the
side of the cap so that it heats both ends at once. All of a sudden it will
move and with luck the surface tension causes it to stick to the iron. Wipe
it off on the sponge.

 

[Ban]

Daniel Kelly (AKA Jack) wrote:

Hi,

I'm in the process of building some PCBs based around a handful of
surface mount ICs. I don't have much experience soldering SMD
components but the ICs I want are only available as SMDs. So my
question is: should I keep the PCBs exclusively SMD or mix SMD and
through-hole components? As I see it, the pros and cons for an
Exclusively SMD design are:

Pros
- Elegant PCB
- Can mount the PCB very close to the base of the container because
there will only be components on one side
- It'll impress my friends!

Cons
- I'm worried about soldering SMDs. Some of those capacitors are damn
small!

Is this about right?

Should I stop worrying about soldering SMD capacitors and resistors?

Thanks,
Jack

Jack,
your terminology is wrong here, "hybrid" is already used for another
mounting technique, where raw chips are directly bonded to a ceramic
substrate and resistors are printed on it. What you are meaning is a mixed
thru-hole/ surface mount stuffing, which is done all the time and for which
no special term exists.
You can do that all easily by hand if you use 0805 and bigger components and
avoid ICs with BGA footprint. There are even technics to solder very dense
IC connections, but I would avoid them in the beginning and only use SO
packages if possible.

--
ciao Ban
Bordighera, Italy

 

[David L. Jones]

"Daniel Kelly \(AKA Jack\)" <d.kellyNOSPAM@NOSPAM.ucl.ac.uk> wrote in message news:<caq5jd$159s$1@uns-a.ucl.ac.uk>...

Hi,

I'm in the process of building some PCBs based around a handful of surface
mount ICs. I don't have much experience soldering SMD components but the
ICs I want are only available as SMDs. So my question is: should I keep the
PCBs exclusively SMD or mix SMD and through-hole components? As I see it,
the pros and cons for an Exclusively SMD design are:

Pros
- Elegant PCB
- Can mount the PCB very close to the base of the container because there
will only be components on one side
- It'll impress my friends!

Cons
- I'm worried about soldering SMDs. Some of those capacitors are damn
small!

Is this about right?

Should I stop worrying about soldering SMD capacitors and resistors?

Yes, stop worrying and give it a go!
Use a nice fine chisel tip and some very small (0.46mm or less) solder
and you'll be fine.
SO package ICs are easy, so are 1206 and 0805 resistors and
capacitors. When you get to 0603 and smaller passives it gets a bit of
pain with home made boards, stick with 0805 minimum. A good pair of
tweezers makes things a breeze.

Solder Mask makes things REAL easy, but when you have a home made
board you don't have that luxury. On home made boards avoid tracks
between SO pads and under 0805 passives etc and you'll live a more
stress free life until you are used to soldering SM.

More Pros/Cons for surface mount:

Pros
- Less holes to drill (I love this one!)
- More robust
- Lighter weight board
- Smaller board
- Cheaper to manufacture board

Cons
- Easier to damage parts and tracks with excess heat
- Can be harder to rework

Dave

 

[budgie]

On 17 Jun 2004 03:30:39 -0700, tronnort@yahoo.com (David L. Jones) wrote:

More Pros/Cons for surface mount:

Pros
- Less holes to drill (I love this one!)
- More robust
- Lighter weight board
- Smaller board
- Cheaper to manufacture board

Cons
- Easier to damage parts and tracks with excess heat
- Can be harder to rework

Dave, you left out one important con of hand-assembled SM - fractures due to
tensile stress after soldering. And in early Tait radios, fractured bonds due
to minor board flex in service.

 

[Bob Stephens]

On 17 Jun 2004 03:30:39 -0700, David L. Jones wrote:

"Daniel Kelly \(AKA Jack\)" <d.kellyNOSPAM@NOSPAM.ucl.ac.uk> wrote in message news:<caq5jd$159s$1@uns-a.ucl.ac.uk>...
Hi,

I'm in the process of building some PCBs based around a handful of surface
mount ICs. I don't have much experience soldering SMD components but the
ICs I want are only available as SMDs. So my question is: should I keep the
PCBs exclusively SMD or mix SMD and through-hole components? As I see it,
the pros and cons for an Exclusively SMD design are:

Pros
- Elegant PCB
- Can mount the PCB very close to the base of the container because there
will only be components on one side
- It'll impress my friends!

Cons
- I'm worried about soldering SMDs. Some of those capacitors are damn
small!

Is this about right?

Should I stop worrying about soldering SMD capacitors and resistors?

Yes, stop worrying and give it a go!
Use a nice fine chisel tip and some very small (0.46mm or less) solder
and you'll be fine.
SO package ICs are easy, so are 1206 and 0805 resistors and
capacitors. When you get to 0603 and smaller passives it gets a bit of
pain with home made boards, stick with 0805 minimum. A good pair of
tweezers makes things a breeze.

Solder Mask makes things REAL easy, but when you have a home made
board you don't have that luxury. On home made boards avoid tracks
between SO pads and under 0805 passives etc and you'll live a more
stress free life until you are used to soldering SM.

More Pros/Cons for surface mount:

Pros
- Less holes to drill (I love this one!)
- More robust
- Lighter weight board
- Smaller board
- Cheaper to manufacture board

Cons
- Easier to damage parts and tracks with excess heat
- Can be harder to rework

Dave

A couple more suggestions. Use liquid flux, fine gauge solder, and if you
can justify the cost get an electronically regulated iron to hold the fine
tip at a constant temperature - makes life with SMD much more enjoyable.


Bob
--
"Just machines that make big decisions
programmed by fellas with compassion and vision."
-D. Fagen
(remove yomama)

 

[Tim Shoppa]

"Tam/WB2TT" <t-tammaru@c0mca$t.net> wrote in message news:<P9udnWIkf80SO03dRVn-jA@comcast.com>...

"Daniel Kelly (AKA Jack)" <d.kellyNOSPAM@NOSPAM.ucl.ac.uk> wrote in message
news:caq5jd$159s$1@uns-a.ucl.ac.uk...
Should I stop worrying about soldering SMD capacitors and resistors?

Parts smaller than 0603 can be a chore to deal with, especially if you've
got hundreds of them to put onto a board. It's a great advantage
to get capacitor and/or resistor arrays in a single package, so that you
solder them just like IC's.

If it's only a few, then it doesn't matter much.

If you are making your own boards, I have two suggestions. First, if at all
possible pick SM IC packages with pitch no smaller than .050.

0.050" is easy... after all the pitch on a TO-92 is 0.050", and hobbyists
have been using those for many decades now (yeah, many cheat and bend the
leads...)

0.65mm or 0.025" is where you start picking up new skills.

Tim.

 

[budgie]

On 17 Jun 2004 17:24:51 -0700, shoppa@trailing-edge.com (Tim Shoppa) wrote:

"Tam/WB2TT" <t-tammaru@c0mca$t.net> wrote in message news:<P9udnWIkf80SO03dRVn-jA@comcast.com>...
"Daniel Kelly (AKA Jack)" <d.kellyNOSPAM@NOSPAM.ucl.ac.uk> wrote in message
news:caq5jd$159s$1@uns-a.ucl.ac.uk...
Should I stop worrying about soldering SMD capacitors and resistors?

Parts smaller than 0603 can be a chore to deal with, especially if you've
got hundreds of them to put onto a board. It's a great advantage
to get capacitor and/or resistor arrays in a single package, so that you
solder them just like IC's.

If it's only a few, then it doesn't matter much.

If you are making your own boards, I have two suggestions. First, if at all
possible pick SM IC packages with pitch no smaller than .050.

0.050" is easy... after all the pitch on a TO-92 is 0.050", and hobbyists
have been using those for many decades now (yeah, many cheat and bend the
leads...)

0.65mm or 0.025" is where you start picking up new skills.

or new language ....

 

[Mike Shonle]

Also, I've found that a nice stereo microscope helps A LOT.

HTH,
-Mike

"Daniel Kelly (AKA Jack)" <d.kellyNOSPAM@NOSPAM.ucl.ac.uk> wrote in message
news:caq5jd$159s$1@uns-a.ucl.ac.uk...

Hi,

I'm in the process of building some PCBs based around a handful of surface
mount ICs. I don't have much experience soldering SMD components but the
ICs I want are only available as SMDs. So my question is: should I keep
the
PCBs exclusively SMD or mix SMD and through-hole components? As I see it,
the pros and cons for an Exclusively SMD design are:

Pros
- Elegant PCB
- Can mount the PCB very close to the base of the container because there
will only be components on one side
- It'll impress my friends!

Cons
- I'm worried about soldering SMDs. Some of those capacitors are damn
small!

Is this about right?

Should I stop worrying about soldering SMD capacitors and resistors?

Thanks,
Jack