1. BIRLA INSTITTUTE OF TECHNOLOGY
MESRA, RANCHI-835215
SURFACE MOUNT TECHNOLOGY
PRESENTED BY:-
SUBHENDRA P. SIGNH(BE/1247/2009)
PAVAN TEJA NAMMI(BE/1248/2009)

2. CONTENTS
 WHAT IS SMT?
 ADVANTAGES OF SMT
 TYPES OF SMT
 SUFACE MOUNT COMPONENTS(SMC)
 SURFACE MOUNT DESIGN
 PROCESS OF MANUFACTURE
 APPLICATIONS OF SMT
 SUMMARY
 REFERENCES

3. WHAT IS SMT ?
A method for constructing electronic circuits in
which the components (SMC, or Surface
Mounted Components) are mounted directly
onto the surface of printed circuit boards (PCBs).
 Electronic devices made for this purpose are
called surface-mount devices or SMDs. And this
technique is known as Surface Mount
Technology

4.  In SMT electronic components are mounted to a printed
circuit board. The solder joint forms the mechanical and
electrical connection.
 Bonding of the solder joint is to the surface of a
conductive land pattern.
 Connection does not use through holes or terminals.

5. ADVANTEGES OF SMT
 Smaller components. Smallest is currently
0.4 x 0.2 mm.
 Denser layout
 Improved shock and vibration characteristics
 Improved frequency response
 Easier to shield from EMI / RFI
 Easier to automate manufacturing
 Reduced board rework costs and time

6. • Fewer holes need to be drilled through abrasive
boards.
• Small errors in component placement are
corrected automatically
• Components can be placed on both sides of the
circuit board.
• Lower resistance and inductance at the
connection
• Better mechanical performance under shake and
vibration conditions.
• SMT parts generally cost less than through-hole
parts.

7. TYPES OF SMT
 SMT replaces DIPs(Dual in package) with
surface mount components.
 When attached to PBs, both active and
passive SMCs form three major types of
SMT assemblies:-
1. TYPE I
2. TYPE II
3. TYPE III

8. TYPES OF SMT
 Type I
(Full SMT board with parts on one or both sides of the
board)
 Type II
(Surface mount chip components are located on the
secondary side of the Printed Board (PB). Active SMCs
and DIPs are then found on the primary side)
 Type III
(They use passive chip SMCs on the secondary side,
but on the primary side only DIPs are used)

9. SURFACE MOUNT COMPONENTS
 Chip resistors, capacitors
 Small outline transistors (SOT)
 PLCC (plastic lead chip carrier)
 QFP, SOIC(gull wing)
 Area array

10. SURFACE MOUNT DESIGN

11. It depends on a number of factors
• Market needs
• Function
• Package moisture sensitivity
• Thermal and solder joints reliability
• As the packaging density increases, thermal problems
are compounded, with a potential adverse impact on
overall product reliability

12. PROCESS OF SMT ASSEMBLY
 Solder paste printing or dispensing
 Component placement
 Reflow
 Inspection
 Rework/backload
 Cleaning

13.  Solder paste printing or dispensing
 Solder paste is applied on the board at the areas where SMC’s
are to be fixed.
 Component placement
 The SMC are then placed on their intended position where the
solder paste is printed

14.  Reflow
 Once parts have been placed on the solder paste bricks, the
entire board is placed in an oven and taken through a
temperature profile like:

15.  Inspection
 Look for wrong/misplaced components and poor solder joints
 Rework/backload
 Fix problems and add parts that can’t survive the high
temperature of the reflow oven
 Cleaning
 Wash to remove flux residues

16. APPLICATIONS OF SMT
 Used to obtain highly accurate and compact circuit
boards
 Used in power amplifier design and modern
communication systems
 Backlighting of legends and LCDs

17. SUMMARY
 Surface Mount Technology is a very reliable
technology for designing PCB’s.
 It provided us high density circuits with proper
reliability.
 It is very accurate and reworks are easy .
 It has a wide application in industry.

18. REFRENCES
1. SURFACE MOUNT TECHNOLOGY EBOOK
 ebookbrowse.com/surface-mount-technology
2. seminarprojects.com/s/surface-mount-technology
3. studygalaxy.com/ordinaryview.php?id=126
4. slideshare.com