Hybrid Circuits
Introduction
Today is the era of getting more
compact and compact. Every one wants every thing to fit pocket physically and financially.
As necessity is the mother of invention so more and more efforts took place to
reduce the size of the assembled product also effectively lowering the cost of
production which ultimately lead to the price lowering.
The two main technologies used to
complete above both tasks are the surface mounted technology popularly called
as SMT and the hybrid technology, which combines many of the basic technologies
on a single platform.
Hybrid circuits -A closer look
The hybrid technology is a combination of both printed on
board and the conventional mounting and soldering technology with more basics
involved as discussed letter. There are only few companies in India
Technical view
Merits of hybrid circuits
- Easy implementation
- Low power dissipation
- Flexible in component rating used
- Thinnest height of board
SMT
The other way in which we get miniaturization
is the surface mount technology abbreviated as SMT. In this the components have
no leads to solder but they are mounted flat on the PCB (printed circuit board)
so decreasing the height and the space to solder.
The components which come in this category are called the SMD
(surface mount devices).They are use full in decreasing the size but they are
limited to low power rating only.
Types of packagings
There categorization depends on the
sizes for two/three terminals, soldering points for integrated circuits and the
type they are soldered or attached to the board
There brief description is as
- Rectangular resistors and capacitors
- 01005: 0.016" × 0.008"
(0.4 mm × 0.2 mm)
- 0201: 0.024" × 0.012" (0.6
mm × 0.3 mm)
- 0402 (1005): 0.04" × 0.02"
(1.0 mm × 0.5 mm)
- 0603 (1608): 0.063" ×
0.031" (1.6 mm × 0.8 mm)
- 0805 (2012): 0.08" × 0.05"
(2.0 mm × 1.25 mm)
- 1206 (3216): 0.126" ×
0.063" (3.2 mm × 1.6 mm)
- 1806 (4516): 0.177" ×
0.063" (4.5 mm × 1.6 mm)
- 1812 (4532): 0.18" × 0.12"
(4.6 mm × 3.0 mm)
- 1825: 0.25" × 0.177" (6.35
mm × 4.5 mm)
- 2512: 0.25" × 0.12" (6.35
mm × 3.0 mm)
- Tantalum capacitors:
o
EIA
3216-12 : 3.2 mm × 1.6 mm × 1.2 mm
o
EIA
3216-18 : 3.2 mm × 1.6 mm × 1.8 mm
o
EIA
3528-12 : 3.5 mm × 2.8 mm × 1.2 mm
o
EIA
3528-21 : 3.5 mm × 2.8 mm × 2.1 mm
o
EIA
6032-15 : 6.0 mm × 3.2 mm × 1.5 mm
o
EIA
6032-28 : 6.0 mm × 3.2 mm × 2.8 mm
o
EIA
7260-38 : 7.2 mm × 6.0 mm × 3.8 mm
o
EIA
7343-20 : 7.3 mm × 4.3 mm × 2.0 mm
o
EIA
7343-31 : 7.3 mm × 4.3 mm × 3.1 mm
o
EIA
7343-43 : 7.3 mm × 4.3 mm × 4.3 mm
- SOD: Small Outline Diode
o
SOD-323:
1.7 × 1.25 × 0.95 mm
o
SOD-123:
3.68 × 1.17 × 1.60 mm
o
SOD-80C:
3.50mm × 1.50mm
- MELF: Metal Electrode Leadless Face
o
Size
0201: L:2.2mm D:1.1mm (solder pads compatible to 0805)
o
Size
0204: L:3.6mm D:1.4mm (solder pads compatible to 1206)
o
Size
0207: L:5.8mm D:2.2mm
- SOT: Small-Outline Transistor
o
SOT-23:
3 mm × 1.75 mm × 1.3 mm
o
SOT-223:
6.7 mm × 3.7 mm × 1.8 mm
o
DPAK
(TO-252): Discrete PAckaging
o
D2PAK
(TO-263):bigger then DPAK
o
D3PAK
(TO-268):bigger then D2PAK
- Few other packaging are
Dual-in-line
o
Small-Outline
Integrated Circuit (SOIC)
o
J-Leaded
Small Outline Package (SOJ)
o
TSOP
-
o
SSOP
-
o
TSSOP
- Thin Shrink Small-Outline package
o
QSOP
- Quarter-Size Small-Outline package
o
VSOP
- Very Small Outline Package
Quad-in-line
o
PLCC
- plastic leaded chip carrier,
o
QFP -
Quad Flat Package,
o
LQFP
- Low-profile Quad Flat Package
o
PQFP
- plastic quad flat-pack
o
CQFP
- ceramic quad flat-pack
o
MQFP
- Metric Quad Flat Pack
o
TQFP
- thin quad flat pack
o
QFN -
quad flat pack
o
LCC-
Leadless Chip Carrier
o
MLP –
Lead frame package
o
PQFN
- power quad flat-pack
Grid arrays
o
PGA -
Pin grid array
o
BGA -
ball grid array
o
LFBGA
- low profile fine pitch ball grid array
o
CGA-
column grid array
o
CCGA
- ceramic column grid array
o
μBGA
- micro-BGA,
o
LLP -
Lead Less Package
o
COB -
chip-on-board
o
COF -
chip-on-flex
o
COG -
chip-on-glass.
o
Non-packaged
devices
The SMD are easier to solder on and place either manually or
by an easy pick-n-place.
Merits of SMT
- Small size
- Lesser area required
- Low power consumption
- Easy to de-solder on reflows
The war continues
As taking in mind the benefits of both the technologies we
are bound to use different technologies at different places depending on the
criteria’s
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