This document discusses Surface Mount Technology (SMT), which involves mounting electronic components directly onto the surface of printed circuit boards rather than inserting them into holes. It provides an overview of SMT, including its advantages over traditional through-hole mounting, different types of SMT, surface mount components, the SMT assembly process, and applications. Key advantages noted are higher density packaging, improved reliability, and easier automation of the manufacturing process.

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