Electronic engineers integrate various types of electronic components called surface-mount devices in their everyday work. Electronic components are a crucial part of electronic devices. There are different types of SMD packages. SMD packages are a certain kind of equipment or component contained within a single packaging. These packages function as component groups that make it much easier to identify their physical qualities. The physical size and characteristics of SMD packages define them.
This article aims to provide the engineers interested in sourcing electronic components in their various sectors well-detailed information about surface mount package sizes, types, and applicable standards.
What Does Surface Mount Package Mean?
SMT components, which use surface mount technology, are available in various types of packaging. There has been reduction in sizes of different packages due to the improvement of surface mount technology. A range of other SMT packages are also available for the integrated circuits, however, this depends on the level of interconnection needed, the technology that is being employed, and a number of other considerations.
There is a wide selection of different SMD packages. A special circuit board with a matching copper design on which they are soldered is usually needed to work with surface-mount boxes. Since there are a various SMD packages, a customer may choose one of these packages according to how convenient an electrical component is for them.
Surface Mount Package Requirements
Most SMT component sizes adhere to the industry standards, of which a large percentage is the JEDEC requirements, to ensure some level of standardization.
Certainly, various SMT packages were utilized for various component types, however the existence of standards makes tasks like PCB design much simpler. Moreover, production is made easier and faster by using packages of standardized sizes. Since pick and place machines may integrate standard feed for SMT components, this will likely streamline the process and as well reduce costs.
Surface Mount Packages Categories
There are standardized packaging for each of the component types, and the various SMT packages may be divided into those categories.
Passive rectangular component
This SMT component comprises capacitors and resistors, which amounts for the majority of the total number of parts utilized. Since technology has made it possible to produce and utilize smaller components, various sizes have been minimized.
Semiconductor SMD package
For semiconductors like diodes, transistors, as well as integrated circuits, you can integrate various surface mount packaging. The broad variance in the needed amount of interconnection is the cause of the huge diversity of SMT packages used for the integrated circuits. Some important packages are listed below.
Packages for transistors and diodes
These packages are frequently integrated for SMD diodes and transistors. Diodes usually feature two electrodes; the package having three electrodes makes it feasible and easy to choose the orientation accurately.
SMD Diode on the Printed Circuit
Although there are other SMT transistor as well as diode packages available, we will be discussing the well-known ones.
SOT-23 – The Small Outline Transistors: This SMT package contains three terminals strictly for the transistor diode. Its dimensions are 3 mm by 1.75 mm by 1.3 mm.
SOT-223 – The Small Outline Transistors: This package can be utilized for applications where higher power is a concern. Its dimensions are 6.7 mm by 3.7 mm by 1.8 mm.
SMD Packages for Integrated Circuits
SMD ICs can be packaged in a variety of ways. Despite the wide variety, each of them has its own use. Small Outline Integrated Circuits: This SMD package includes gull wing lead that features a 1.27 mm pin spacing as well as the dual in line layout.
Small Outline Packaging
There are many iterations of this particular SMD package. These include:
- TSOP, or Thin Small Outline Packaging, is a thinner SMD package than the small outline integrated circuit SOIC with 0.5 mm pin spacing.
- Shrink Small Outline Packaging (SSOP) – This features a pin spacing of 0.635 mm.
- TSSOP – This is the Thin Shrink Small Outline Packages:
- Quarter-sized Small Outline Packaging: The pin spacing is 0.635 mm.
Very Small Outline Packaging (VSOP): This is a smaller version of the QSOP and features pin spacing of 0.65, 0.5, or 0.4 mm.
There is a general term that represents a flat container for IC. This term is known as QFP, or quad flat pack, is a general term for a flat container used for ICs. This is a list of the various variations. Low profile quad flat pack also known as LQFP has pins across all its four sides. Its height is 1.4 mm, although the spacing of this pin may vary based on the integrated circuit.
PQFP – The Plastic Quad Flat Packs: The square plastic packaging has an equal number of pins in the shape of gull wings on every side. Usually with at least 44 pins and a narrow spacing.
CQFP – The Ceramic Quad Flat Packs: This is the ceramic variant of a PQFP.
TQFP: This is a smaller variant of the PQFP is the TQFP, or Thin Quad Flat Packs.
BGA: The ball grid array is an integrated circuit package which enables electrical contact with a printed circuit board through pads that are beneath the package. This terminology was coined from the fact that the pads look like solder balls before the process of soldering.
PCB manufacturers integrating these package pads may place them beneath package; this offers solutions to some of the problems associated with the extremely thin leads required for quad flat packages. When it comes to BGAs, the spacing of the ball is exactly 1.27 mm.
Applications of Surface Mount package
Most printed circuit board design manufactured in various quantities integrates surface mount packages. There could be a level of uniformity despite having a wide array of diverse packages. This level of uniformity can still be achieved. In any case, this usually results from the variation in the performance and functioning of these components.
SMD or SMT?
People always confuse SMT with SMD. They interchange these two terminologies. However, there is a difference between the two. So, what is the difference between SMD and SMT? The main difference between surface mount technology and surface mount device is that SMD is an electronic component usually installed on a printed circuit board. On the other hand, SMT is a technique in which these electronic components are mounted on the bare circuit board. A bare circuit board has no surface mount device on it.
The SMD device
One thing you need to know is that lead-based components differ from the build-up components. The surface mount device (SMD) parts are designed in such a way that they are soldered to a board instead of linking between two locations.
In conventional leaded components, the leads don’t always go via the holes in the circuit board. There are different kinds of components. Therefore, there are various ways of packaging these components. Among the packaging styles, you can distinguish three different broad types. These types of SMD component packages are passive components, diodes and transistors, and also integrated circuits. We are discussing these types of SMD below:
Passive SMDs
The passive SMDs require the use of various packaging options. However, it should be noted that most passive SMDs are SMD capacitors or SMD resistors. In this case, the package sizes will be extremely defined. Crystals, coils, and other components commonly have more unique needs. Therefore, these components always come with their own containers.
Furthermore, capacitors and resistors are available in a wide range of package sizes. These resistors or capacitors have the identifiers 0201, 0402, 0603, 0805, 1206, and 1812. These measurements are in centimeters and are indicated by the numerals. This means that the 1206 has a dimension of 12 by 6 hundredths of the inch. The bigger sizes, like 1206 and 1812, were among the first utilized.
Diodes and Transistors
Manufacturers make use of small plastic packages to package SMD transistors and SMD diodes. The cables are bent to ensure they maintain a contact with the circuit board when they are removed from the box are used to make the connections.
Integrated Circuits
When it comes to packaging ICs, various types of packaging is used. A particular package is usually integrated. However, this depends on the level of interconnectivity needed. While certain circuit boards, like basic logic chips, might just require about 16 or 14 pins. VLSI processors and related chips, may require a minimum of 200 pins. There are many distinct packages available due to the huge range of needs.
Small outline integrated circuit can be used to package smaller chips. These are essentially the SMT versions of the popular Dual In Line (DIL) packaging utilized by the popular 74 series logical chips. Also, there are other smaller variants that can be used. This includes the thin Small Outline Packages and Shrink Small Outline Packages.
Size of Surface Mount Packages
What is a 0201 SMD?
Devices with a surface mount include resistors, transistors, capacitors, and more. It is important to note that SMD component packages are usually available in various sizes. You will find these sizes marked on these SMD components. This helps in distinguishing the sizes from one another. This 0201 SMD packages also has dimensions of 0.024″ by 0.012″, or 0.6 by 0.3 mm.
This 0201 SMD is specifically designed to increase dependability in applications where spacing is a top priority. Portable electronics like tablets and cellphones are one of these use cases. It should be noted that careful handling is required when assembling these 0201 SMD parts.
Understanding the Imperial and Metric codes for the 0201 SMD
There are two distinct ways to express SMD component sizes. Finding these methods might be quite difficult for component purchasers.
It can be confusing to differentiate how imperial or metric codes are used. However, these codes are quite easy to understand if you pay attention. The numerical code represents the size of the components.
Also, you can express imperial code in inches. For example, the 0201 imperial codes indicates a component is 0.02 x 0.01 inches in size. Metric codes are measured in millimeters. For instance, using 0201 SMD metric codes denotes a component which has a size of 0.2 x 0.1 mm.
Surface – Mounted Discrete Resistors
The thin film and the thick film are the two types of surface mount resistor.
The Thick Film Surface – mounted Resistors: Rather than deposit the resistive films on circular cores like axial resistors, the SMD is made by the screening ruthenium dioxide-based paste and perhaps a comparable substance on high-purity, flat alumina substrate surfaces.
Thin Film Resistors: They are built on the ceramic substrates with a protective covering, sometimes known as the glass coating, and have silver coated as thick film pastes on a ceramic substrate present on these terminators.
This resistor seems to have a resistive layer having protective coating on one side as well as white base layer on the other. Hence it is easy to differentiate capacitors and resistors based on their external appearance.
Ceramic Capacitors for Surface Mount
When you are in need of an SMD packaging ideal for high-frequency circuits, you need to consider the surface mount capacitor. You can position this below the container somewhat on the opposite side of the circuit board. This application SMT capacitors serve as decoupling applications including frequency control.
LCCC – Leadless Ceramic Chip Carriers
The castellation terminations on the LCCC are groove-shaped, gold-plated terminations which provide shorter signal routes and more operating frequencies.
However, it is possible to categorize the leadless ceramic chip carriers in many families based on its specific package pitch. 50 mil leaded ceramic chip carrier groups are very popular. However, there are other families which 20, 25, and 40 mil.
Conclusion
Over the past years, there has been a huge development on the production of printed circuit boards. The sizes of these boards have been reduced due to the introduction of integrated circuits. These tiny boards are capable of holding several components. However, it is of utmost importance to ensure components and wires on the PCB are well installed. This is because improper installation can result in short circuits and other problems. Therefore, you need to pay precise attention when choosing surface mount devices and components.
