Flatpack (electronics)

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A TTL logic gate in a flat pack package KL TI SN5451 Logic IC.jpg
A TTL logic gate in a flat pack package
Flat pack integrated circuits in the Apollo guidance computer Agc flatp.jpg
Flat pack integrated circuits in the Apollo guidance computer

Flatpack is a US military standardized printed-circuit-board surface-mount-component package. The military standard MIL-STD-1835C defines: Flat package (FP). A rectangular or square package with leads parallel to base plane attached on two opposing sides of the package periphery.

Printed circuit board board to support and connect electronic components

A printed circuit board (PCB) mechanically supports and electrically connects electronic components or electrical components using conductive tracks, pads and other features etched from one or more sheet layers of copper laminated onto and/or between sheet layers of a non-conductive substrate. Components are generally soldered onto the PCB to both electrically connect and mechanically fasten them to it.

Surface-mount technology method for producing electronic circuits

Surface-mount technology (SMT) is a method for producing electronic circuits in which the components are mounted or placed directly onto the surface of printed circuit boards (PCBs). An electronic device so made is called a surface-mount device (SMD). In industry, it has largely replaced the through-hole technology construction method of fitting components with wire leads into holes in the circuit board. Both technologies can be used on the same board, with the through-hole technology used for components not suitable for surface mounting such as large transformers and heat-sinked power semiconductors.


The standard further defines different types with varying parameters which includes package body material, terminal location, package outline, lead form and terminal count.

Terminal (electronics) Connection point in electronic circuits

A terminal is the point at which a conductor from an electrical component, device or network comes to an end and provides a point of connection to external circuits. A terminal may simply be the end of a wire or it may be fitted with a connector or fastener. In network analysis, terminal means a point at which connections can be made to a network in theory and does not necessarily refer to any real physical object. In this context, especially in older documents, it is sometimes called a pole. On circuit diagrams, terminals for external connections are denoted by empty circles. They are distinguished from nodes that are entirely internal to the circuit, which are denoted by solid circles.

Lead (electronics) connecting wire or pad within an electronic device; electrical connection consisting of a length of wire or metal pad (SMD) that comes from a device

In electronics, a lead is an electrical connection consisting of a length of wire or a metal pad (SMD) that is designed to connect two locations electrically. Leads are used for many purposes, including: transfer of power; testing of an electrical circuit to see if it is working, using a test light or a multimeter; transmiting information, as when the leads from an electrocardiograph, or ECG are attached to a person's body to transmit information about their heart rhythm; and sometimes to act as a heatsink. The tiny leads coming off through-hole components are also often called pins.

The main vehicle for testing of high reliability flatpack packages has been MIL-PRF-38534 (General Specification for Hybrid Microcircuits). This document outlines the general requirements of fully assembled devices, whether they are single chip, multichip, or of hybrid technology. The test procedures of these requirements are found in MIL-STD-883 (Test Methods and Procedures for Microelectronics) as a listing of test methods. These methods cover various aspects of the minimum requirements that a microelectronics device must be able to attain before it is considered a compliant device. [1]

The MIL-PRF-38534 specification establishes the general performance requirements for hybrid microcircuits, multi-chip modules (MCM) and, similar devices and the verification and validation requirements for ensuring that these devices meet the applicable performance requirements. Verification is accomplished through the use of one of two quality programs. The main body of this specification describes the performance requirements and the requirements for obtaining a Qualified Manufacturers List (QML) listing. The appendices of this specification are intended for guidance to aid a manufacturer in developing their verification program. Detail requirements, specific characteristics, and other provisions that are sensitive to the particular intended use should be specified in the applicable device acquisition specification.

The MIL-STD-883 standard establishes uniform methods, controls, and procedures for testing microelectronic devices suitable for use within military and aerospace electronic systems including basic environmental tests to determine resistance to deleterious effects of natural elements and conditions surrounding military and space operations; mechanical and electrical tests; workmanship and training procedures; and such other controls and constraints as have been deemed necessary to ensure a uniform level of quality and reliability suitable to the intended applications of those devices. For the purpose of this standard, the term "devices" includes such items as monolithic, multichip, film and hybrid microcircuits, microcircuit arrays, and the elements from which the circuits and arrays are formed. This standard is intended to apply only to microelectronic devices.


A Flatpack integrated circuit on a circuit board, among TO-5 packages Flatpack IC on board .jpg
A Flatpack integrated circuit on a circuit board, among TO-5 packages

The original flatpack was invented by Y. Tao in 1962 while working for Texas Instruments to achieve improved heat dissipation. The dual in-line package would be invented two years later. The first devices measured 1/4 inch by 1/8 inch (3.2 mm x 6.4 mm) and had 10 leads. [2]

Texas Instruments American company that designs and makes semiconductors

Texas Instruments Inc. (TI) is an American technology company that designs and manufactures semiconductors and various integrated circuits, which it sells to electronics designers and manufacturers globally. Its headquarters are in Dallas, Texas, United States. TI is one of the top ten semiconductor companies worldwide, based on sales volume. Texas Instruments's focus is on developing analog chips and embedded processors, which accounts for more than 80% of their revenue. TI also produces TI digital light processing (DLP) technology and education technology products including calculators, microcontrollers and multi-core processors. To date, TI has more than 43,000 patents worldwide.

Dual in-line package

In microelectronics, a dual in-line package, or dual in-line pin package (DIPP) is an electronic component package with a rectangular housing and two parallel rows of electrical connecting pins. The package may be through-hole mounted to a printed circuit board (PCB) or inserted in a socket. The dual-inline format was invented by Don Forbes, Rex Rice and Bryant Rogers at Fairchild R&D in 1964, when the restricted number of leads available on circular transistor-style packages became a limitation in the use of integrated circuits. Increasingly complex circuits required more signal and power supply leads ; eventually microprocessors and similar complex devices required more leads than could be put on a DIP package, leading to development of higher-density packages. Furthermore, square and rectangular packages made it easier to route printed-circuit traces beneath the packages.

The flat package was smaller and lighter than the round TO-5 style transistor packages previously used for integrated circuits. Round packages were limited to 10 leads. Integrated circuits needed more leads to take full advantage of increasing device density. Since flat packages were made of glass, ceramic and metal, they could provide hermetic seals for circuits, protecting them from moisture and corrosion. Flat packs remained popular for military and aerospace applications long after plastic packages became the standard for other application fields.

TO-5 designation for a standardized metal semiconductor package

In electronics, TO-5 is a designation for a standardized metal semiconductor package used for transistors and some integrated circuits. The TO element stands for "transistor outline" and refers to a series of technical drawings produced by JEDEC.

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Wire bonding

Wire bonding is the method of making interconnections (ATJ) between an integrated circuit (IC) or other semiconductor device and its packaging during semiconductor device fabrication. Although less common, wire bonding can be used to connect an IC to other electronics or to connect from one printed circuit board (PCB) to another. Wire bonding is generally considered the most cost-effective and flexible interconnect technology and is used to assemble the vast majority of semiconductor packages. Wire bonding can be used at frequencies above 100 GHz.

Integrated circuit packaging Final stage of semiconductor device fabrication

In electronics manufacturing, integrated circuit packaging is the final stage of semiconductor device fabrication, in which the block of semiconductor material is encapsulated in a supporting case that prevents physical damage and corrosion. The case, known as a "package", supports the electrical contacts which connect the device to a circuit board.

Secure voice encrypted voice communication

Secure voice is a term in cryptography for the encryption of voice communication over a range of communication types such as radio, telephone or IP.

A United States defense standard, often called a military standard, "MIL-STD", "MIL-SPEC", or (informally) "MilSpecs", is used to help achieve standardization objectives by the U.S. Department of Defense.

Integrated logistic support (ILS) is an integrated and iterative process for developing materiel and a support strategy that optimizes functional support, leverages existing resources, and guides the system engineering process to quantify and lower life cycle cost and decrease the logistics footprint, making the system easier to support. Although originally developed for military purposes, it is also widely used in commercial product support or customer service organisations.


MIL-STD-810, Environmental Engineering Considerations and Laboratory Tests, is a United States Military Standard that emphasizes tailoring an equipment's environmental design and test limits to the conditions that it will experience throughout its service life, and establishing chamber test methods that replicate the effects of environments on the equipment rather than imitating the environments themselves. Although prepared specifically for military applications, the standard is often used for commercial products as well.

Quad Flat No-leads package

Flat no-leads packages such as quad-flat no-leads (QFN) and dual-flat no-leads (DFN) physically and electrically connect integrated circuits to printed circuit boards. Flat no-leads, also known as micro leadframe (MLF) and SON, is a surface-mount technology, one of several package technologies that connect ICs to the surfaces of PCBs without through-holes. Flat no-lead is a near chip scale plastic encapsulated package made with a planar copper lead frame substrate. Perimeter lands on the package bottom provide electrical connections to the PCB. Flat no-lead packages include an exposed thermal pad to improve heat transfer out of the IC. Heat transfer can be further facilitated by metal vias in the thermal pad. The QFN package is similar to the quad-flat package (QFP), and a ball grid array (BGA).

The human-body model (HBM) is the most commonly used model for characterizing the susceptibility of an electronic device to damage from electrostatic discharge (ESD). The model is a simulation of the discharge which might occur when a human touches an electronic device.

The military standard referred to as MIL-E-7016F, Electric Load and Power Source Capacity, Aircraft, Analysis of" addresses the methods and analysis of electric loads and source capacity on military aircraft. The use of the document is approved for use by all departments and agencies of the United States Department of Defense (DoD). Although prepared specifically for DoD applications, the standard may be tailored for commercial applications as well.

MIL-PRF-38535 is a United States military specification that establishes the general performance and verification requirements of single die integrated circuit device type electronics. It is a performance-based specification document defining the general requirements, as well as the quality assurance and reliability requirements, for the manufacture of microelectronic or integrated circuits used in military applications and high-reliability microcircuit application programs.

Reliability of semiconductor devices can be summarized as follows:

  1. Semiconductor devices are very sensitive to impurities and particles. Therefore, to manufacture these devices it is necessary to manage many processes while accurately controlling the level of impurities and particles. The finished product quality depends upon the many layered relationship of each interacting substance in the semiconductor, including metallization, chip material and package.
  2. The problems of micro-processes, and thin films and must be fully understood as they apply to metallization and wire bonding. It is also necessary to analyze surface phenomena from the aspect of thin films.
  3. Due to the rapid advances in technology, many new devices are developed using new materials and processes, and design calendar time is limited due to non-recurring engineering constraints, plus time to market concerns. Consequently, it is not possible to base new designs on the reliability of existing devices.
  4. To achieve economy of scale, semiconductor products are manufactured in high volume. Furthermore, repair of finished semiconductor products is impractical. Therefore, incorporation of reliability at the design stage and reduction of variation in the production stage have become essential.
  5. Reliability of semiconductor devices may depend on assembly, use, and environmental conditions. Stress factors affecting device reliability include gas, dust, contamination, voltage, current density, temperature, humidity, mechanical stress, vibration, shock, radiation, pressure, and intensity of magnetic and electrical fields.
Transit case

A transit case is a hard-sided case intended for protecting defined contents during transportation. In some forms, the interior is filled with foam which has pockets molded or cut into it that equipment specifically fits into. Some transit cases are provided with foam inserts that completely fill the interior and the user can pluck out pieces to make the case fit a particular application. Many camera cases are built in this fashion allowing the user to tailor the interior foam to their particular equipment. The outside of the transit case provides protection against the environment and a first level of protection against mechanical damage such as shock. The interior foam or other structure cushions the equipment against shock and vibration and some protection against rapid temperature changes.

A semiconductor package is a metal, plastic, glass, or ceramic casing containing one or more discrete semiconductor devices or integrated circuits. Individual components are fabricated on semiconductor wafers before being diced into die, tested, and packaged. The package provides a means for connecting the package to the external environment, such as printed circuit board, via leads such as lands, balls, or pins; and protection against threats such as mechanical impact, chemical contamination, and light exposure. Additionally, it helps dissipate heat produced by the device, with or without the aid of a heat spreader. There are thousands of package types in use. Some are defined by international, national, or industry standards, while others are particular to an individual manufacturer.

An operating temperature is the temperature at which an electrical or mechanical device operates. The device will operate effectively within a specified temperature range which varies based on the device function and application context, and ranges from the minimum operating temperature to the maximum operating temperature. Outside this range of safe operating temperatures the device may fail. Aerospace and military-grade devices generally operate over a broader temperature range than industrial devices; commercial-grade devices generally have the narrowest operating temperature range.

Co-fired ceramic

Co-fired ceramic devices are monolithic, ceramic microelectronic devices where the entire ceramic support structure and any conductive, resistive, and dielectric materials are fired in a kiln at the same time. Typical devices include capacitors, inductors, resistors, transformers, and hybrid circuits. The technology is also used for robust assembly and packaging of electronic components multi-layer packaging in the electronics industry, such as military electronics, MEMS, microprocessor and RF applications.


  1. AMETEK ECP Website http://www.ametek-ecp.com/solutions/electronicpackaging/qualitysupport
  2. Dummer, G.W.A. Electronic Inventions and Discoveries 2nd ed. Pergamon Press ISBN   0-08-022730-9