Transcript Flexible Printed Wiring Board

Chapter 4
Components for Electronic Systems
• Description of geometrical, thermal and some electrical
properties of main types of components. No description
of electrical properties of monolithic circuits.
The course material was developed in INSIGTH II, a project sponsored by
the Leonardo da Vinci program of the European Union
Electronic Pack….. Chapter 4 Components for Electronic Systems
Slide 1
Hole Mounted Resistors
• Mature design, fig. 4.1:
–Carbon composite (a)
–Metal film (b)
–Wire wound (c)
Electronic Pack….. Chapter 4 Components for Electronic Systems
Slide 2
Surface Mounted Resistors
• Fig.4.2.a: Thick film layers on ceramic
substrate, rectangular shape
Electronic Pack….. Chapter 4 Components for Electronic Systems
Slide 3
Surface Mounted Resistors
Fig. 4.2 b): Metal system for termination on SMD resistors.
Electronic Pack….. Chapter 4 Components for Electronic Systems
Slide 4
Surface Mounted Resistors
Fig. 4.2 c): MELF-resistors have cylindrical body.
(MELF is acronym for Metal Electrode Face Bonding)
Electronic Pack….. Chapter 4 Components for Electronic Systems
Slide 5
Surface Mounted Resistors
Table 4.1.
Properties of SMD resistors (Philips).
Resistance range and tolerance
10 ohm to 1 Mohm (E24* series) ± 2%
1 ohm to 10 Mohm (E24 series) ± 5%
1 ohm to 10 Mohm (E12 series) ±10%
Dimensions
3,2 x 1,6 x 0,6 mm
Operating temperature range
-55°C to + 155°C
Temperature coefficient (-40°C to 125°C) <+200 x 10-6/K
Absolute max. dissipation at Tamb= 70°C 0,25 W
Maximum permissible voltage
200 V (r.m.s.)
Climatic category (IEC68)
55/155/56
Jumper resistance
= 50 mohm
Maximum current
2A
*See Table 4.2
• Table 4.1: Properties of SMD resistors
Electronic Pack….. Chapter 4 Components for Electronic Systems
Slide 6
Surface Mounted Resistors
Table. 4.2: The resistance series E24, E12 and E6. The numbers mean that for
example in series E6 there are 6 resistance values for each decade: 10,
15, 22, 33, 47 and 68 x10n ohms.
• Table 4.2: The resistance series E24,
6 16 18 20 22 24 27 30 33 36 39 43 47 51 56 62 68 75 82 91
E24 12
10 11and
12 13 15
E12 10
E6 10
12
15
15
18
22
22
27
33
33
39
47
47
Electronic Pack….. Chapter 4 Components for Electronic Systems
56
68
82
68
Slide 7
Hole Mounted Resistors
• Coding:
Color
Value
Multiplier
Tolerance
(%)
Black
0
0
-
Brown
1
1
±1
Red
2
2
±2
Orange
3
3
±0.05
Yellow
4
4
-
Green
5
5
±0.5
Blue
6
6
±0.25
Violet
7
7
±0.1
Gray
8
8
-
White
9
9
-
Gold
-
-1
±5
Silver
-
-2
±10
None
-
-
±20
Electronic Pack….. Chapter 4 Components for Electronic Systems
Slide 8
Capacitors
• In addition the capacitance, the following properties are
important:
• Maximum voltage rating
• Temperature dependence of the capacitance (temperature
coefficient)
• Loss tangent (tan δ), see below
• Equivalent series resistance
• Long term stability and ageing phenomena
• High frequency properties
• Leakage current
• Ability to withstand various production processes (high
temperature, etc.)
• Price, physical size, etc.
• Web: www.interq.or.jp/japan/se-inoue/e_capa.htm
Electronic Pack….. Chapter 4 Components for Electronic Systems
Slide 9
Capacitors, continued
• Main types:
–Ceramic multilayer
–Electrolytic dry, polarized
–Electrolytic, wet, polarized
–Metallized plastic film
–Mica
Electronic Pack….. Chapter 4 Components for Electronic Systems
Slide 10
Capacitors, continued
• Electrical model:
C
A = electrode area
C = (eo er • A) /d
d= electrode distance
| Z | = [ Rs2 + (wL - 1/wC)2]1/2
Rs = series resistance (Rp neglected),
L = inductance, fig. 4.5
Resonance frequency will be when:
Rp
L
wL = 1/wC
Rs
C
Loss tangent:
tan d = R / | Im Z | = { Rp + Rs [1+ (wCRp)2 ]} / [ wCRp2 - w L (1+ (wCRp)2]
Electronic Pack….. Chapter 4 Components for Electronic Systems
Slide 11
Capacitors, continued
• Fig. 4.3: Electrical
equivalent model for
capacitor. If Rp can be
neglected the impedance is
given by:
Rp
L
Rs
C
| Z | = [Rs2 + (wL - 1/wC)2]1/2
• Fig. 4.4: The frequency
dependence of impedance
for multilayer ceramic
capacitors (below) and
tantalum electrolytic
capacitors (top), all having
100 nF capacitance value.
Electronic Pack….. Chapter 4 Components for Electronic Systems
Slide 12
Capacitors, continued
Fig. 4.5: Frequency dependence of the loss tangent tan d
schematically.
tan d = R / |Im Z | = [Rp + Rs ( 1+ ( wCRp)2) ] / ( wCRp2 - w L (1+ ( wCRp)2) ]
Electronic Pack….. Chapter 4 Components for Electronic Systems
Slide 13
Capacitors, continued
• Multilayer Ceramic Capacitors
Fig. 4.7.a: SMD Multilayer Ceramic Capacitor
Fig. 4.7.b: Metal system for the end
termination of multilayer ceramic
capacitors.
Electronic Pack….. Chapter 4 Components for Electronic Systems
Slide 14
Multilayer Ceramic
Capacitor, continued
• Class 1: Low
capacitance, good
electrical properties,
types NP0, N220, N750,
COG, etc.
• Class 2: High
capacitance, poorer
electrical behaviour,
types X7R, Z5U
Fig. 4.8: Relative dielectric constant for ferroelectric ceramic
compositions (class 2), as a function of temperature, near the Curie
point
Electronic Pack….. Chapter 4 Components for Electronic Systems
Slide 15
Fig. 4.9: Properties
of dielectrics of the
types NP0, X7R and
Z5U in SMD
ceramic multilayer
capacitors.
Multilayer Ceramic
Capacitors, continued
Top: The voltage
dependence of
capacitance.
Middle: Loss
tangent as function
of temperature.
Bottom: The
temperature
coefficient of the
capacitance
(Philips).
Electronic Pack….. Chapter 4 Components for Electronic Systems
Slide 16
Multilayer Ceramic Capacitors, continued
Fig. 4.10: Crack formation because of thermal stress
in ceramic capacitors
Electronic Pack….. Chapter 4 Components for Electronic Systems
Slide 17
Capacitors, continued
• Tantalum, Dry Electrolytic
–Very high capacitance, low voltages, low
leakage current
Fig. 4.11 a): Tantalum SMD electrolytic capacitor (Philips),
and hole mounted tantalum capacitors (Siemens) Tantalum
oxide is Ta2O5.
Electronic Pack….. Chapter 4 Components for Electronic Systems
Slide 18
Capacitors, continued
• Electrolytic Capacitors – why they are polarised:
– The capacitance is the oxidised surface of the anode
– Reversed polarity will remove the oxide by reduction reaction
at the anode and loss of dielectric isolation leading to shortcircuiting
Fig. 4.11 a): Tantalum SMD electrolytic capacitor (Philips),
and hole mounted tantalum capacitors (Siemens)
Electronic Pack….. Chapter 4 Components for Electronic Systems
Slide 19
Capacitors, continued
• Tantalum, Dry Electrolytic
Dissipation factors vary with temperature: Maximum values which are not exceeded by any capacitor
are as follows.
Temperature
Rated Voltage 4 to 10 V d.c.
Rated Voltage 15 to 50 V d.c.
-55C
10%
8%
25C
12%
6%
85C
12%
6%
125C
12%
6%
The d.c. leakage current (at rated voltage) is within the limit set below
25C <
85C <
125C <
0,01 µA/µF V
0,10 µA/µF V
0,125 µA/µF V
or
or
or
<
<
<
1 µA
10 µA
12,5 µA
whichever is greater
whichever is greater
whichever is greater
Fig. 4.11 b): Electrical properties of dry tantalum electrolytic
capacitors. (Data from Philips)
Electronic Pack….. Chapter 4 Components for Electronic Systems
Slide 20
Wet Electrolytic Aluminium Capacitors
Fig. 4.12 a): Aluminium electrolytic capacitor for SMD
mounting. (From Philips)
Electronic Pack….. Chapter 4 Components for Electronic Systems
Slide 21
Wet Electrolytic Aluminium Capacitors
Fig. 4.12 b):
Aluminium electrolytic
capacitor properties
(Philips).
Top: Temperature
dependence of the
capacitance, relative to
the value at 20 °C.
Middle: Temperature
dependence of tan d.
Bottom: Temperature
dependence of
impedance at a
frequency of 10 kHz.
Electronic Pack….. Chapter 4 Components for Electronic Systems
Slide 22
Diodes and Transistors
Fig. 4.13: Axial, plastic encapsulated, hole mounted diodes to the left.
Centre: A plastic can with metal base for power diodes. It can be hole
mounted or surface mounted, depending on how the leads are bent. The
base is screwed to the substrate.
Right: A higher power diode in a metal can. Screw mounted to the
substrate for efficient thermal contact.
Electronic Pack….. Chapter 4 Components for Electronic Systems
Slide 23
Diodes and Transistors, continued
Fig. 4.14: Various types of hole mounted transistor packages:
a) Left: Plastic packages,
b) Centre: Low power metal packages
c) Right: Metal package for high power transistors. For the
high power package, the collector is connected to the metal
body.
Electronic Pack….. Chapter 4 Components for Electronic Systems
Slide 24
Diodes and Transistors , continued
Fig. 4.15: MELF-package for SMD diodes. The standard size is
designated SOD-80, with dimensions shown to the right.
(MELF: Metal Electrode Face Bonding)
Electronic Pack….. Chapter 4 Components for Electronic Systems
Slide 25
Diodes and Transistors, continued
Fig. 4.16: SOT-packages for SMD diodes and transistors: The most
common, SOT-23 top left, SOT-89 for power transistors in the middle, and
SOT-143 with four terminals to the right. The dimensions for SOT-23 are
shown bottom left, and a cut-through SOT-89 in the middle. Ceramic SMD
transistor packages with terminal placement like for SOT-23 are shown
bottom right.
Electronic Pack….. Chapter 4 Components for Electronic Systems
Slide 26
IC Packages
• Plastic or Ceramic IC Packages?
• Plastic:
–
–
–
–
–
–
–
Not hermetic
Low price in large quantities
High initial cost
Low thermal conductivity
Limited time at high temperature
Thermal mismatch to Si chip and metals
Not suitable for for high frequency circuits
• Ceramic:
–
–
–
–
Hermetic, good reliability
Costly, but OK for prototyping
Good thermal conductivity
Low thermal coefficient of expansion, matches well with Si, mismatch to
organic substrates
– Gold metallization must be removed
– Well defined high frequency properties
Electronic Pack….. Chapter 4 Components for Electronic Systems
Slide 27
Packages for Hole Mounted ICs
Fig. 4.17:a) DIP (Dual-in-line) IC package. b) Partly crosssectioned DIP package which shows the silicon chip, bonding
wires, lead frame and plastic body. c) The terminal organisation
for 4 two-input NOR gates in a 14 pins package.
Electronic Pack….. Chapter 4 Components for Electronic Systems
Slide 28
Packages for Hole Mounted ICs,
continued
Fig. 4.18: Pin grid packages: To the left a cavity up ceramic
package, and to the right a plastic moulded package.
Electronic Pack….. Chapter 4 Components for Electronic Systems
Slide 29
SMD IC Packages
• Small Outline (SO)
• Plastic Leaded Chip Carrier (PLCC)
• Leadless Chip Carrier (LLCC)
• Leaded Ceramic Chip Carrier (LDCC)
• Flatpack, mini-flatpack
• TapePak
• Chip Scale Packages
Electronic Pack….. Chapter 4 Components for Electronic Systems
Slide 30
SMD IC Packages, continued
Fig. 4.19: Surface mounted SO (Small Outline) IC package.
(From Philips)
Electronic Pack….. Chapter 4 Components for Electronic Systems
Slide 31
SMD IC Packages, continued
Outline
SO
SO-8
SO-8
SO-14
SO-16
SO-16L
SO-20
SO-24
SO-28
VLO-40
VSO-56
Encapsulation
Maximum width
Maximum length
[mm]
[mm]
4,0
5,00
7,6
7,6
4,0
8,75
4,0
10,00
7,6
10,5
7,6
13,0
7,6
15,6
7,6
18,1
7,6
15,5
11,1
21,6
Maximum width
Lead end to lead end
[mm]
6,2
12,4
6,2
6,2
10,65
10,65
10,65
10,65
12,8
15,8
Table 4.3: Dimensions for SO- and VSO packages. Centre-tocentre lead distance is normally 50 mils, except for VSO-40
with 30 mils and VSO-56 with 0.75 mm.
Electronic Pack….. Chapter 4 Components for Electronic Systems
Slide 32
SMD IC Packages:
Plastic Leaded Chip Carrier (PLCC)
Fig. 4.20: Plastic leaded chip carrier with (PLCC). They are normally
square with an equal number of terminals on all four sides (top). For large
DRAMs, the package has terminals on only two sides, also being called
SOJ. The bottom figure shows a 1 or 4 Mbit DRAM package.
Electronic Pack….. Chapter 4 Components for Electronic Systems
Slide 33
SMD IC Packages:
Plastic Leaded Chip Carrier (PLCC)
Leads Format
Lead pitch
20
28
44
52
68
18
28
32
[mm]
1,27
1,27
1,27
1,27
1,27
1,27
1,27
1,27
5x5
7x7
11x11
13x13
17x17
5x4
9x5
9x7
Maximum body
dimensions [AxB]
[mm]
9,1x9,1
11,6x11,6
16,8x16,8
19,3x19,3
24,4x24,4
10,9x7,5
14,1x9,0
14,1x11,6
Maximum Device
Dimensions (LxW)
[mm]
10,1x10,1
12,6x12,6
17,8x17,8
20,3x20,3
25,4x25,4
11,9x8,5
15,1x10,0
15,1x12,6
Typical
Height (C)
[mm]
3,5-4,7
3,5-4,7
3,5-4,7
3,5-4,7
3,5-4,7
3,5-4,7
3,5-4,7
3,5-4,7
Table 4.4: Dimensions for PLCC packages. Format means the
number of terminals on two neighbouring sides.
Electronic Pack….. Chapter 4 Components for Electronic Systems
Slide 34
Leadless Chip Carrier (LLCC)
Leaded Ceramic Chip Carrier (LDCC)
Fig. 4.21 a): The various types of ceramic chip carriers [4.15].
Types A -D to the left are leadless (LLCC), whereas types A
and B to the right are meant for mounting leads (LDCC).
Electronic Pack….. Chapter 4 Components for Electronic Systems
Slide 35
Leadless Chip Carrier (LLCC)
Fig. 4.21 b): LLCC packages, additional details. The longest
terminal is to designate electrical terminal number 1 in the
circuit.
Electronic Pack….. Chapter 4 Components for Electronic Systems
Slide 36
Leadless Chip Carrier (LLCC),
continued
Leads
Format
20
28
44
52
68
84
18
28
32
5x5
7x7
11x11
13x13
17x17
21x21
5x4
9x5
9x7
Pad Pitch (p)
[mm]
1,27
1,27
1,27
1,27
1,27
1,27
1,27
1,27
1,27
Maximum Dimension (AxB)
[mm]
9,1x9,1
11,6x11,6
16,8x16,8
19,3x19,3
24,4x24,4
29,6x29,6
10,9x7,5
14,1x9,0
14,1x11,6
Table 4.5. LLCCs, dimensions.
Electronic Pack….. Chapter 4 Components for Electronic Systems
Slide 37
Leaded Ceramic Chip Carrier
(LDCC)
Fig. 4.22: Leaded ceramic chip carriers.
Electronic Pack….. Chapter 4 Components for Electronic Systems
Slide 38
Leaded Ceramic Chip Carrier
(LDCC), continued
Fig. 4.23: Various shapes of the leads, and leadless
termination for comparison.
Electronic Pack….. Chapter 4 Components for Electronic Systems
Slide 39
Flatpacks
Fig. 4.24: Quad flatpack with leads on all four sides.
Flatpacks are usually made of plastic or ceramic. They have
leads on four or two sides.
Electronic Pack….. Chapter 4 Components for Electronic Systems
Slide 40
Mini-flatpacks
Fig. 4.25: Mini-flatpacks is a name for higher density
flatpacks: Typically 84 - 244 terminals and a pitch of 25 mils.
Electronic Pack….. Chapter 4 Components for Electronic Systems
Slide 41
TapePak
Fig. 4.26: National Semiconductor´s TapePak component packages are
specified with terminal numbers between 40 and close to 600. To the left
we see a 40 leads TapePak in the form it is received by the user with a
protective ring around it, and test points outside the ring. To the right is
TapePak 40 after excising and lead bending, seen from above and from
the side.
Electronic Pack….. Chapter 4 Components for Electronic Systems
Slide 42
High Performance Packages
• Multilayer ceramic, Al2O3 or AlN
–Ground planes
–Controlled characteristic impedance
–Thermal vias
Electronic Pack….. Chapter 4 Components for Electronic Systems
Slide 43
High Performance Packages
Fig. 4.27: Thermal via-holes in the printed circuit board, for
better heat conduction.
Electronic Pack….. Chapter 4 Components for Electronic Systems
Slide 44
High Performance Packages
Fig. 4.28: Multilayer package for high frequency GaAs circuits with 3
ground planes, 2 voltage planes, 1 signal layer and a top conductor layer
for contacts and sealing (Triquint).
Electronic Pack….. Chapter 4 Components for Electronic Systems
Slide 45
High Performance Packages,
continued
Fig. 4.29: Multichip package for memory module in a
Hitachi high-performance computer [4.18]. The module
contains 6 ECL chips, mounted by flip chip.
Electronic Pack….. Chapter 4 Components for Electronic Systems
Slide 46
Packages: Future Trends
Fig. 4.30: Comparison between the size of various package
forms for an integrated circuit with approximately 64
terminals.
Electronic Pack….. Chapter 4 Components for Electronic Systems
Slide 47
Packages: Future Trends, continued
Fig. 4.31: History and prognosis for the use of various sizes
of passive SMD components, in percentage of the total
number.
Electronic Pack….. Chapter 4 Components for Electronic Systems
Slide 48
Metallization of Terminals
• Passives
–Ag in alloy with Pd, Ni barrier, Sn/Pb
–Ag in solder alloy
–With adhesive mounting:
• No Sn/Pb on terminal
• ICs
–Au removed
–Sn/Pb coating
Electronic Pack….. Chapter 4 Components for Electronic Systems
Slide 49
Terminal Metallization,
Solderability and Reliability
Fig. 4.32: Strain at fracture of solder fillet as function of gold
concentration in the solder metal, relative to value without gold.
Electronic Pack….. Chapter 4 Components for Electronic Systems
Slide 50
Electrostatic Discharges (ESD)
• Unprotected MOS: Max 5 - 80 V on input
before destroyed
• Triboelectricity: >>1000 V discharge
• Billions of $ damage annually
• Protected circuits tolerate 500 - 8000 V
• Extensive precautions in industry, handling
and packing
Electronic Pack….. Chapter 4 Components for Electronic Systems
Slide 51
Electrostatic Discharges - Component
Damages and Precautions
Fig. 4.33: MOS transistor schematically. The gate oxide is
very vulnerable for damage by electrostatic discharge. Gate
oxides down below 200 Å (20 nm) are now used.
Electronic Pack….. Chapter 4 Components for Electronic Systems
Slide 52
Electrostatic Discharges - Component
Damages and Precautions, continued
Fig. 4.34: CMOS circuit exposed to electrostatic damage:
Silicon has molten in a small area. Picture size  5m x 5m.
Electronic Pack….. Chapter 4 Components for Electronic Systems
Slide 53
Electrostatic Discharges - Component
Damages and Precautions, continued
Fig. 4.35: ESD protection circuit at in- and outputs for MOS and
for bipolar circuits.
Electronic Pack….. Chapter 4 Components for Electronic Systems
Slide 54
Component Packaging
• Paper tape (hole mounted passives)
• Blister tape (SMD passives, discretes, small
ICs)
• Sticks (DIPs, SMD ICs)
• Waffle trays (Flatpacks)
• Stack magazine
• Bulk: Not suited for automatic mounting
Electronic Pack….. Chapter 4 Components for Electronic Systems
Slide 55
Component Packaging
for Automatic Placement
Fig. 4.36: Blister tape for surface mounted components.
Standard dimensions for 8 mm wide tape.
Electronic Pack….. Chapter 4 Components for Electronic Systems
Slide 56
Component Packaging
for Automatic Placement
Fig. 4.37: Plastic sticks as packaging for SMD integrated
circuits.
Electronic Pack….. Chapter 4 Components for Electronic Systems
Slide 57
Component Packaging
for Automatic Placement
Fig. 4.38: Waffle trays packaging for flatpacks to the left,
frame for stacking of single component to the right.
Electronic Pack….. Chapter 4 Components for Electronic Systems
Slide 58
End of Chapter 4
Components for Electronic Systems
• Important issues:
–Components:
• Distinguish between the different components
–Packages for electronic devices :
• Distinguish between the different packages
–Electrostatic discharges
–Component packaging:
• Used for automatic assembly machines
Electronic Pack….. Chapter 4 Components for Electronic Systems
Slide 59