GLOSSARY of Printed Circuits

       J

Index to terms on this page:

JEDEC   JEITA   JEP95   JIC   jitter   J-lead   JSON   JTAG  

JEDEC — Joint Electron Device Engineering Council Solid State Technology Association, formerly known as Joint Electron Device Engineering Council (JEDEC) or Joint Electron Device Engineering Councils, is an independent semiconductor engineering trade organization and standardization body of the Electronic Industries Alliance (EIA), a trade association that represents all areas of the electronics industry in the United States. JEDEC was founded in 1958 as a joint activity between EIA and the National Electrical Manufacturers Association (NEMA) to develop standards for semiconductor devices. JEDEC has over 300 members, including some of the world's largest computer companies. Headquarters: 3103 North 10th Street, Arlington, VA 22201
https://www.jedec.org/

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JEITA — Japan Electronics and Information Technology Industries Association is a Japanese trade organization for the electronics and IT industries. It was formed in 2000 from two earlier organizations, the Electronic Industries Association of Japan and the Japan Electronic Industries Development Association.

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JEP95 — JEDEC Registered and Standard Outlines for Solid State and Related Products, is a compilation of some 3000 pages of outline drawings for microelectronic packages including transistors, diodes, DIPS, chip carriers, sockets, and package interface BGA outlines in both inch and metric versions. There are over 500 registrations in all.

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JIC — - Just In Case. (of a circuit element) Provided as an option in case it is needed in the future. "JIC" can be added to the netname or net label.

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jitter — Instability of a signal in either its amplitude or its phase or both. [Graf, Rudolf F. Modern Dictionary of Electronics. Newnes, 1999]

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J-lead — (JAY-leed)  Pronunciation Key  noun  [Components] A narrow, flat lead that extends from the edge of a surface mount device (SMD) and curls under the body of the component, resembling in profile a letter J. The curved portion of the J is down and is the solder contact point. (Contrast with gull wing.)

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JSON — (computer languages) Initialism of JavaScript Object Notation, a data format used to represent structured data. It is based on JavaScript syntax. It is often referred to as JSON schema. Coordinate terms: XML, YAML

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JTAG — Joint Test Action Group (developer of IEEE Standard 1149.1-1990) [pronounced "JAY-tag"]

1. A standard specifying how to control and monitor the pins of compliant devices on a printed circuit board.
   Each device has four JTAG control lines. There is a common reset (TRST) and clock (TCLK). The data line daisy chains one device's TDO pin (data output) to the TDI (data input) pin on the next device.
   The protocol contains commands to read and set the values of the pins (and optionally internal registers) of devices. This is called "boundary scanning." The protocol makes board testing easier as signals that are not visible at the board connector may be read and set.
   The protocol also allows the testing of equipment, connected to the JTAG port, to identify components on the board (by reading the device identification register) and to control and monitor the device's outputs.
   JTAG is not used during normal operation of a board. Cited works:
   https://foldoc.org/JTAG
   For more information see Boundary Scan Tutorial
2. JTAG port
3. JTAG connector, the physical connector portion of the JTAG port 4)(in a PCB database) a decal representation of the JTAG header, of which there is only one on any one PCB.