1. Advanced Skills Soldering Class
Instructor: Ted Markson

2. Lecture Goals Learn about Surface Mount Technology
Become familiar with more-complex soldering techniques
View demonstrations of common SMT procedures
Hands-on assembly with a SMD kit
Basic Skills Soldering Class
9/20/2018

3. Surface Mount Technology
Basic Skills Soldering Class
9/20/2018

4. What is SMT? Acronym for ‘Surface Mount Technology’
Method for assembling components onto a PCB surface
The leading circuit board assembly practice
Basic Skills Soldering Class
9/20/2018

5. SMT Compared to Thru-hole Technology
Smaller component size, i.e. smaller land pattern
Higher density components, i.e. more connections to the board
Less solder used in assembly
Basic Skills Soldering Class
9/20/2018

6. SMT Advantages Smallest and most-dense component packages
Simplified setup for automated assembly
Quick assembly
Automatic physical error correction
Reliably repeatable end-products
Lower cost in general, per unit (components, assembly, setup, tooling)
Highest performance of end-product
RF signal effects
Lowered inductance via pin-to-pad connection
Basic Skills Soldering Class
9/20/2018

7. SMT Disadvantages Difficult single-unit assembly or repair
Difficult QA and inspection
SMDs are prototyping-prohibitive
Basic Skills Soldering Class
9/20/2018

8. SMT Component Packages
Refer to Electronic Industry Alliance for latest specifications
Basic Skills Soldering Class
9/20/2018

9. 2-pin Packages Numeric Outlines Small Outline Diode (SOD)
The component size is a reference to actual dimensions
Generally passive components such as resistors and capacitors
For example, 1206 (3216 metric) is x 0.063 in (3.2 x 1.6mm)
Small Outline Diode (SOD)
For example, SOD-123 is 3.68 x 1.17 x 1.60mm
Basic Skills Soldering Class
9/20/2018

10. Few-pin Packages Small Outline Transistors (SOT)
Usually in 3, 5, or 6-pin packages
Common components are transistors and voltage regulators
For example, SOT-23 is usually 2.9 x 1.3mm
Discrete Packaging (DPAK, D2PAK, D3PAK)
Common components are voltage regulators and MOSFETS
D2PAK is a common equivalent to TO-220
Basic Skills Soldering Class
9/20/2018

11. Multi-pin Packages, Dual In-line
Acronym
Name
Description
SOIC
Small-outline Integrated Circuit
8+ pins
Gull-wing lead form
1.27 mm lead pitch
SOJ
J-leaded Small-outline
Like SOIC with J-leads
TSOP
Thin Small-outline Package
Thinner than SOIC
0.5 mm lead pitch
SSOP
Shrink Small-outline Package
0.635 or 0.8 lead pitch
TSSOP
Thin Shrink Small-outline Package
Lead pitch varies
QSOP
Quarter-size Small-outline Package
0.635 mm lead pitch
VSOP
Very Small Outline Package
0.4, 0.5, or 0.65 mm lead pitch
DFN
Dual Flat No-lead
Basic Skills Soldering Class
9/20/2018

12. Multi-pin Packages, Quad In-line
Acronym
Name
Description
PLCC
Plastic Leaded Chip Carrier
Square
QFP
Quad Flat Package
LQFP
Low-profile Quad Flat Package
1.4 mm height
PQFP
Plastic Quad Flat-pack
44+ leads
CQFP
Ceramic Quad Flat-pack
MQFP
Metric Quad Flat-pack
Metric lead pitch
TQFP
Thin Quad Flat-pack
Thinner version of PQFP
QFN
Quad Flat No-lead
LCC
Leadless Chip Carrier
Contacts are vertically recessed
MLP
Micro Lead-frame Package
0.5 mm lead pitch, no pins
PQFN
Power Quad Flat No-lead
Exposed die pads for heat-sinking
Basic Skills Soldering Class
9/20/2018

13. Multi-pin Packages, Grid Arrays
Acronym
Name
Description
BGA
Ball Grid Array
Rectangular array of solder balls, 1.27 mm typical pitch
LGA
Land Grid Array
Mates with on-board socket
FBGA
Fine Pitch Grid Array
Pitch less than 1.27 mm
LFBGA
Low Profile Fine Pitch Ball Grid Array
0.8 mm typical pitch
TFBGA
Thin Fine Pitch Ball Grid Array
CGA
Column Grid Array
Rectangular array of solder cylinders or columns
CCGA
Ceramic Column Grid Array
Ceramic bodied CGA
µBGA
Micro BGA
Ball pitch less than 1 mm
LLP
Lead-less Package
0.5 mm typical ball pitch
Basic Skills Soldering Class
9/20/2018

14. Soldering Specifics
Basic Skills Soldering Class
9/20/2018

15. SMT Production Assembly Techniques
Manual Placement
Human using a soldering station to assemble components
Speed per item is comparable to thru-hole assembly, though the time per pin is much greater
QA is usually done with automated processes, such as X-ray examination, Ultrasonic testing, and/or Electrode testing
Automated Placement
Solder paste is applied via stencil and screen print process
Components placed onto board with pick-and-place machine
Soldering procedure is completed in-batch using Infrared or Hot gas methods
QA is usually done with automated processes
Basic Skills Soldering Class
9/20/2018

16. Land Patterns Used to describe the arrangement of pads on a PCB
While there are package standards, some components use package variants with different land patterns
Proper patterns can always be found in datasheet or by contacting manufacturer
Guideline: verify land patterns with component specs if pattern has not been tested in one month. Pay attention to easily-varied details: lead pitch and pad size
Basic Skills Soldering Class
9/20/2018

17. Joints
Good mechanical connection when possible – let the pad contact the PCB pad before soldering
Clean the pads before placing the component
Proper heat transfer from iron to target: Tip the tip!
Avoid ‘cold’ and ‘mounding’ joints
Mis-aligned components are more common in SMT
Tack-down multi-pin components
Still be weary of pad stress from re-heating and lifting PCB pads
Basic Skills Soldering Class
9/20/2018

18. Soldering Techniques - Intro
Inside to outside
Smallest to largest
Basic Skills Soldering Class
9/20/2018

19. Soldering Techniques - Heat-and-slide
For ‘2-pin’ or ‘few-pin’ packages
Use conical tip
Clean area with isopropyl alcohol or liquid flux
Grab component with tweezers
Heat single pad, then slide component into land pattern
Remove iron from single pad
Verify proper component alignment to land pattern
Connect other pads
Clean area with alcohol and let dry
Basic Skills Soldering Class
9/20/2018

20. Soldering Techniques - Sweep
For all package types
Use hoof, blade, or chisel tip
Clean area with isopropyl alcohol or liquid flux
Apply flux to target pads
Hold component to board with tape or by tacking
Melt solder onto tip
Slide tip with solder into joint(s), wait for solder flow into pads, slide tip away
Repeat sliding procedure until all pads connected
Clean area with alcohol and let dry
Basic Skills Soldering Class
9/20/2018

21. Soldering Techniques - Drag
For all package types
Use hoof or conical tip
Clean area with isopropyl alcohol or liquid flux
Apply flux to target pads
Hold component to board with tape or by tacking
Melt solder onto tip
Drag tip with solder along pads parallel to IC edge, with sufficient force to allow solder to connect pin and pad
Verify heel, side, and toe fillet joints
Clean area with alcohol and let dry
Basic Skills Soldering Class
9/20/2018

22. Demonstration http://www.youtube.com/watch?v=5uiroWBkdFY
Basic Skills Soldering Class
9/20/2018

23. Questions?
Basic Skills Soldering Class
9/20/2018

24. Build Your Kit!
Basic Skills Soldering Class
9/20/2018