SDIP is a packaging technology used for the packaging of integrated circuits (ICs).SDIP package is a dual-row inline package, which is characterized by a dense arrangement of two closely spaced IC pins in the same package volume.
The SDIP package was commonly used for earlier integrated circuits, especially in the 1970s and 1980s. It was designed due to the limitations of packaging technology to provide more pins in a limited space. By placing two rows of pins in a single package, the SDIP package is able to provide a higher pin density, thereby accommodating more functionality in a smaller size.
Although the SDIP package was very common in the past, it has been replaced by smaller, higher density package forms (e.g., QFP, BGA, etc.) as technology has advanced. As a result, modern integrated circuits rarely use SDIP packages. However, for some specific applications or older electronic devices, integrated circuits in SDIP packages may still be used.
SDIP Package Characteristics
SDIP packages have the following characteristics:
Dual Row In-Line Package: The SDIP package is a dual row in-line package with pins arranged in two rows, typically for a pitch of 2.54 mm (0.1 inch). This makes it compatible with standard in-line sockets and easy to plug and service.
Higher Pin Density: The SDIP package offers a higher pin density in the same size package volume than the traditional single row in-line package. By densely arranging two closely spaced pins in a single package, SDIP packages are able to provide more pins and thus accommodate more functions.
Suitable for early integrated circuits: The SDIP package was particularly popular in the past, especially in the 1970s and 1980s. It was designed due to the limitations of packaging technology and provided a solution for early integrated circuits with a high-density pin layout.
Relatively large size: SDIP packages are relatively large compared to modern packaging technologies. This is due to the extra space required for its dual row pin layout and the limitations of manufacturing at earlier process levels.
Gradual replacement: As technology has advanced, smaller, higher density package forms (e.g., QFP, BGA, etc.) have replaced SDIP packages. Modern integrated circuits rarely use SDIP packages, especially in new designs and high-performance applications. However, for some specific applications or older electronic devices, integrated circuits in SDIP packages may still be used.
SDIP Package Pinouts
The SDIP package is a scaled-down version of the DIP package, also known as SH-DIP, with a pin pitch of 1.778 mm.The pinout of the SDIP package is a double-row inline arrangement, where each row has a series of pins.The number of pins in the SDIP package can be in a variety of variants, the following are common:
SDIP-32: has 32 pins. Each row has 16 pins for a total of two rows.
SDIP-40: Has 40 pins. Each row has 20 pins, totaling two rows.
SDIP-64: has 64 pins. Each row has 32 pins, totaling two rows.
It is important to note that although the above are some of the common SDIP package variants, there can actually be different pin counts and arrangements depending on the specific needs and design. Therefore, the number of pins and layout of SDIP packages may vary depending on the particular IC.
SDIP Package Materials
The following materials are typically used for SDIP packages:
Package Substrate: The substrate of an SDIP package is a structure that supports and connects the pins. It is usually made of a non-conductive material such as ceramic (e.g. ceramic substrate) or plastic (e.g. plastic substrate).
Package Case: The package case is the external shell that protects and encapsulates the IC. It is usually made of plastic or metal materials to provide mechanical strength and protect the internal circuitry. Common materials include plastic (e.g., thermoplastic resin) or metal (e.g., aluminum alloy).
Pins: Pins are the interface that connects the IC to the external circuitry. They are usually made of a metallic material such as copper alloy or gold-plated copper. Pins can be soldered or inserted into the circuit board to make electrical and mechanical connections.
Wires: During the packaging process, the pins need to be connected to the circuitry inside the IC. This is usually accomplished by means of microscopically thin metal wires, such as aluminum or gold wires. These wires are soldered or attached to the metal connection points between the pin and the IC to establish the circuit connection.
It is important to note that the specific materials used for SDIP packages may vary depending on the manufacturer, package specifications, and the particular application. The materials listed above are common choices, but some variations may occur in actual applications.
SDIP Packaging Processes
The process for SDIP encapsulation involves the following major steps:
Substrate Preparation: A suitable substrate material is selected, usually ceramic or plastic. The substrate is cut to the appropriate size and surface treated to provide good adhesion.
Wiring: Micro-fine metal wires are used to connect the pins to the connection points inside the IC. This can be accomplished by soldering, gold wire bonding, or other joining techniques.
Package Assembly: Placing the IC chip on the substrate and securing it in place by adhesives or soldering. At the same time, it is ensured that the pins are properly aligned with the substrate.
Overlay: Using the package enclosure material (e.g., plastic or metal) to create an overlay that completely encapsulates the chip and pins, providing mechanical protection and insulation.
Pin Handling: Pins typically need to be cut to the proper length and passivated to improve their corrosion resistance and solderability.
Pin Shaping: After packaging, pins may need to be shaped to facilitate insertion into standard sockets or connection to a circuit board.
Testing and Inspection: Functional tests and visual inspections are performed to ensure that the packaged IC meets specifications.
It is important to note that specific SDIP packaging processes may vary depending on the manufacturer, package specifications and technical requirements. The above is only a general approach process, but there may be some variations and additional steps in actual production.
SDIP Packaging Advantages and Disadvantages
SDIP packaging has the following advantages and disadvantages.
Main Advantages:
High Pin Density: The SDIP package provides a higher pin density in the same size package volume as compared to the traditional single row inline package. This allows more features and connections to be accommodated in a smaller size.
Inline Design: The SDIP package utilizes an inline design, making it easy to plug and unplug into standard sockets or connect to a circuit board. This facilitates maintenance and replacement operations.
Lower cost: Compared to some modern packaging technologies such as BGA or CSP, SDIP packages are less expensive to manufacture because they do not require complex solder balls or microscopic connections.
High compatibility: thanks to a standard two-row inline layout, the SDIP package is compatible with many existing boards and sockets, making it easy to integrate into existing systems.
Key Disadvantages:
Larger size: SDIP packages are larger in size relative to modern packaging technologies (e.g., QFP, BGA). This limits its use in certain space-constrained or small devices.
Limited pin count: Although the SDIP package can provide a high pin density, it still has a limited number of pins relative to some modern package forms. This can limit applications in certain high-density functional requirements.
Limits high frequency applications: Due to its larger package size and pin spacing, the SDIP package has relatively poor high frequency performance. For high frequency applications, more advanced package technologies may be more suitable.
Unsuitable for high-temperature applications: SDIP packages typically use plastic substrates and package housings, which have relatively low high-temperature resistance. Therefore, it may not be suitable for applications that operate for long periods of time in high temperature environments.
Summarization
SDIP is an electronic chip packaging technology, especially in the 1980s and 1990s widely used in integrated circuits. In fact, it is a scaled-down version of the DIP, the entire device is smaller than the conventional DIP circle, due to the soldering is not particularly convenient, has been rarely used in integrated circuits, is now rare, and is gradually replaced by smaller packages of SMD packages, such as TQFP, SOP, BGA and so on. However, it may still be seen in some older electronic components.