Engineering:TO-8
In electronics, TO-8 is a designation for a standardized metal semiconductor package. TO in TO-8 stands for "transistor outline" and refers to a series of technical drawings produced by JEDEC.[1] The TO-8 package is noticeably larger than the more common TO-5 package. While originally designed for medium power transistors (that is, higher power than TO-5 but lower than TO-3) such as the 2N1483 series[2] or the AD136,[3] it is more commonly used for integrated circuits and sensors (see Variants below).
Construction
The typical TO-8 metal can package has a base diameter of 15.24 mm (0.600 in), a cap diameter of 12.29 mm (0.484 in), and a cap height of 7.62 mm (0.300 in).[1] The lead diameter is nominally 0.76 mm (0.030 in). The leads are arranged on a circle with a diameter of 7.16 mm (0.282 in). The minimum length of the leads is 10.16 mm (0.400 in).
Variants
Several variants of the original TO-8 package have the same cap dimensions but differ in the number and length of the leads (wires). Somewhat incorrectly, TO-8 is often used in manufacturer's literature as a synonym for any package with the cap dimensions of TO-8, regardless of the number of leads, or even for any package with the diameter of TO-8, regardless of the cap height and the number of leads. Light-sensitive or light-emitting devices have a transparent window, lens, or parabolic reflectors in the top of the case rather than a sealed, flat top.[4][5] There are variants with between 2 and 16 leads.[6] For packages with more than 4 leads, the leads are usually arranged along the edges of a square with a side length of 10.16 mm (0.400 in) (rather than on a circle as in packages with up to 4 leads or for other metal can packages such as TO-101).[7] These variants usually have a tab to identify lead number 1 and an increased cap diameter of 13.97 mm (0.550 in).[7]
National standards
TO-233 is intended to replace previous definitions of TO-8.[8][9]
| Standards organization | Standard | Designation for |
|---|---|---|
| TO-8 | ||
| JEDEC | JEP95[9] | TO-233-AA |
| IEC | IEC 60191[lower-alpha 1][10] | C8/B13 |
| DIN | DIN 41878[3] | 8A3 |
| EIAJ / JEITA | ED-7500A[lower-alpha 1][11] | TC-6/TB-7 |
| British Standards | BS 3934[lower-alpha 1][10] | SO-22/SB3-9 |
References
- ↑ 1.0 1.1 "JEDEC TO-8 package specification". Archived from the original on 2016-04-10. https://web.archive.org/web/20160410013132/http://www.jedec.org/sites/default/files/docs/archive/to/to-008.pdf. Retrieved 2021-10-23.
- ↑ "2N1483 – 2N1486". Microsemi. 2013. https://www.microsemi.com/document-portal/doc_download/132281-2n1483-2n1484-2n1485-2n1486-npn-bjt-series-datasheet. Retrieved 2021-10-23.
- ↑ 3.0 3.1 "Germanium PNP Transistor AD136 40V / 10A DATASHEET" (in de). Siemens. https://www.web-bcs.com/pdf/SH/AD/AD136.pdf. Retrieved 2021-10-25.
- ↑ 4.0 4.1 "LMM-244-# Planar multi channel pyroelectric detector". InfraTec. https://www.infratec.de/downloads/en/sensor-division/detector_data_sheet/infratec-datasheet-lmm-244-_.pdf. Retrieved 2021-10-25.
- ↑ "Photodigm TO-8 Package". Photodigm. http://www.photodigm.com/to-8-package. Retrieved 2021-10-25.
- ↑ "TO-8 Package". 2008. https://eesemi.com/to8.htm. Retrieved 2021-10-25.
- ↑ 7.0 7.1 Larry Davis (2012-01-21). "Transistor Package Style 12-Lead TO-8 Can". http://www.interfacebus.com/semiconductor-transistor-packages-12-Lead-TO-8-Package-Dimensions.html. Retrieved 2021-10-25.
- ↑ "Index by Device Type of Registered Transistor Outlines (TO)". JEDEC Publication No. 95. JEDEC. October 2010. https://www.jedec.org/sites/default/files/TOIND_DT.pdf. Retrieved 2021-07-13.
- ↑ 9.0 9.1 "Header Family 0.280 Pin Circle". 1976-06-01. http://www.jedec.org/sites/default/files/docs/archive/to/to-233.pdf. Retrieved 2021-10-25.
- ↑ 10.0 10.1 "Semiconductors". Pro Electron. 1978. pp. 215-221. https://datasheet.datasheetarchive.com/originals/scans/Scans-110/150.pdf. Retrieved 2021-06-17.
- ↑ "EIAJ ED-7500A Standards for the Dimensions of Semiconductor Devices". JEITA. 1996. https://home.jeita.or.jp/tsc/std-pdf/ED-7500A.pdf.
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