[{"data":1,"prerenderedAt":65},["ShallowReactive",2],{"blog-2n2222-pinout-pcb-assembly-en":3},{"title":4,"description":5,"date":6,"lastUpdated":6,"category":7,"image":8,"readingTime":9,"wordCount":10,"timeRequired":11,"htmlContent":12,"faq":13,"tags":29,"slug":33,"sourceLocale":34,"availableLocales":35,"jsonld":41},"2N2222 Pinout Verification for PCB Design and Assembly","Verify a 2N2222-family transistor by exact part number, numbered pins, PCB footprint and assembly orientation before release.","2026-11-11","assembly","/assets/blogs/2n2222-pinout-pcb-assembly/numbered-pin-to-pad.svg",12,2234,"PT12M","\u003Cp>\u003Cstrong>Do not release a 2N2222-family transistor for assembly based on the family name or a generic pinout diagram.\u003C/strong> Start with the manufacturer’s full part number, its specified package, and the current manufacturer datasheet. Then trace each numbered device pin through the schematic symbol to the numbered PCB pad and its net. Separately verify the physical footprint, assembly side, and orientation.\u003C/p>\n\u003Cp>A matching pin-number table is necessary, but it does not by itself prove that the footprint, assembly direction, electrical design, availability, or a substitute is acceptable.\u003C/p>\n\u003Cp>For related decisions, use the \u003Ca href=\"/en/blog/circuit-board-components/\">component identification guide\u003C/a> to recognize and document parts, the \u003Ca href=\"/en/blog/pcb-component-substitution-approval/\">component substitution approval checklist\u003C/a> when a proposed part changes, and the \u003Ca href=\"/en/blog/pick-and-place-file-checklist/\">placement file checklist\u003C/a> when the chosen assembly process requires placement data. They serve different purposes: identification is not substitution approval, and a placement file is not a pinout verification.\u003C/p>\n\u003Ch2>Start with the exact part, not the family name\u003C/h2>\n\u003Cp>“2N2222” describes a family of transistor designations, not a complete assembly instruction. A drawing or library entry bearing that name may not identify the manufacturer, ordering variant, package details, or document revision needed for a particular board.\u003C/p>\n\u003Cp>For the intended build, collect:\u003C/p>\n\u003Cul>\n\u003Cli>The manufacturer and \u003Cstrong>full manufacturer part number\u003C/strong> from the approved BOM.\u003C/li>\n\u003Cli>The package and any relevant lead-form or ordering-variant information.\u003C/li>\n\u003Cli>The current manufacturer datasheet and package drawing applicable to that part.\u003C/li>\n\u003Cli>The revision of the schematic, PCB design, and assembly documents under review.\u003C/li>\n\u003Cli>The board reference designator that connects those records to the intended component.\u003C/li>\n\u003C/ul>\n\u003Cp>Record the document title and revision used for the decision. If a source is historical, mark it as such rather than treating it as proof of the current specification or supply status. Confirm current lifecycle, change notices, and traceable availability through the manufacturer or an authorized supply channel.\u003C/p>\n\u003Cp>A package label such as TO-92 is useful for finding the relevant drawing, but it does not replace the complete part number or establish how a specific PCB footprint must be oriented.\u003C/p>\n\u003Cdiv data-component=\"BlogQuickQuoteInline\">\u003C/div>\n\n\u003Ch2>A historical numbered-pin example\u003C/h2>\n\u003Cp>The historical \u003Cstrong>\u003Ca href=\"https://www.onsemi.com/download/data-sheet/pdf/p2n2222a-d.pdf\">onsemi P2N2222A/D Rev. 7 datasheet\u003C/a>\u003C/strong>, dated January 2013, identifies TO-92 CASE 29 STYLE 17 for the listed \u003Cstrong>P2N2222AG\u003C/strong>. In that specific source, the numbered assignment is:\u003C/p>\n\u003Ctable>\n\u003Cthead>\n\u003Ctr>\n\u003Cth>Manufacturer device pin\u003C/th>\n\u003Cth>Terminal\u003C/th>\n\u003C/tr>\n\u003C/thead>\n\u003Ctbody>\u003Ctr>\n\u003Ctd>1\u003C/td>\n\u003Ctd>Collector\u003C/td>\n\u003C/tr>\n\u003Ctr>\n\u003Ctd>2\u003C/td>\n\u003Ctd>Base\u003C/td>\n\u003C/tr>\n\u003Ctr>\n\u003Ctd>3\u003C/td>\n\u003Ctd>Emitter\u003C/td>\n\u003C/tr>\n\u003C/tbody>\u003C/table>\n\u003Cp>This is a historical, specific-part source—not a universal 2N2222-family pinout, a current datasheet, or evidence that P2N2222AG is currently in stock. For a real release, obtain and review the current manufacturer documentation for the exact intended part.\u003C/p>\n\u003Cp>The assignment also does not describe a physical left-to-right sequence on a board. Manufacturer package drawings, CAD views, and assembly drawings can use different viewing conventions. Trace the \u003Cstrong>numbered leads\u003C/strong> using the stated view in each applicable document; do not compare the apparent left-to-right order of differently viewed drawings.\u003C/p>\n\u003Ch2>Trace a fictional design from pin to pad\u003C/h2>\n\u003Cp>The following is a \u003Cstrong>fictional schematic and PCB net example\u003C/strong> using only the historical numbered assignment above. The net names, symbol, reference designator, and PCB pads are illustrative; they are not claims about an existing board or an approved library.\u003C/p>\n\u003Cp>\u003Cimg src=\"/assets/blogs/2n2222-pinout-pcb-assembly/numbered-pin-to-pad.svg\" alt=\"Logical mapping from numbered device pins to fictional schematic pins, nets, and PCB pads\">\u003C/p>\n\u003Cp>\u003Cem>Logical mapping only: the rows do not show the physical lead positions, viewing direction, board side, or assembly orientation.\u003C/em>\u003C/p>\n\u003Ctable>\n\u003Cthead>\n\u003Ctr>\n\u003Cth>Device pin and terminal in the historical source\u003C/th>\n\u003Cth>Fictional symbol pin\u003C/th>\n\u003Cth>Fictional schematic net\u003C/th>\n\u003Cth>Fictional PCB pad\u003C/th>\n\u003C/tr>\n\u003C/thead>\n\u003Ctbody>\u003Ctr>\n\u003Ctd>1 — collector\u003C/td>\n\u003Ctd>Q_EXAMPLE, pin 1\u003C/td>\n\u003Ctd>\u003Ccode>COLLECTOR_LOAD\u003C/code>\u003C/td>\n\u003Ctd>Q_EXAMPLE, pad 1\u003C/td>\n\u003C/tr>\n\u003Ctr>\n\u003Ctd>2 — base\u003C/td>\n\u003Ctd>Q_EXAMPLE, pin 2\u003C/td>\n\u003Ctd>\u003Ccode>BASE_CONTROL\u003C/code>\u003C/td>\n\u003Ctd>Q_EXAMPLE, pad 2\u003C/td>\n\u003C/tr>\n\u003Ctr>\n\u003Ctd>3 — emitter\u003C/td>\n\u003Ctd>Q_EXAMPLE, pin 3\u003C/td>\n\u003Ctd>\u003Ccode>EMITTER_RETURN\u003C/code>\u003C/td>\n\u003Ctd>Q_EXAMPLE, pad 3\u003C/td>\n\u003C/tr>\n\u003C/tbody>\u003C/table>\n\u003Cp>The intended logical result is that each symbol pin and PCB pad bearing the same number carries the same named net. That makes the example useful for a connectivity review, but it leaves several separate questions unanswered:\u003C/p>\n\u003Cul>\n\u003Cli>Does the actual CAD symbol assign collector, base, and emitter to those numbered pins?\u003C/li>\n\u003Cli>Does the actual footprint assign each pad number to the corresponding \u003Cstrong>physical lead\u003C/strong> of the specified part?\u003C/li>\n\u003Cli>Are the hole and pad geometry, lead form, and mechanical clearance suitable?\u003C/li>\n\u003Cli>Does the assembly drawing show the correct board side and orientation?\u003C/li>\n\u003Cli>Is the part electrically and thermally suitable for the actual circuit?\u003C/li>\n\u003C/ul>\n\u003Cp>The table answers none of those questions on its own. It also gives no physical orientation for the fictional part.\u003C/p>\n\u003Cp>For example, suppose a PCB report instead lists pad 1 on \u003Ccode>EMITTER_RETURN\u003C/code> and pad 3 on \u003Ccode>COLLECTOR_LOAD\u003C/code>. Those entries conflict with this fictional schematic: hold the design, trace the symbol-to-footprint mapping and PCB nets, correct the responsible design data, and regenerate the controlled outputs before reviewing again. Do not simply rename the nets to make a report look consistent. Even after the logical mismatch is corrected, the physical lead-to-pad check remains separate.\u003C/p>\n\u003Ch2>How to cross-check the design records\u003C/h2>\n\u003Ch3>Check the manufacturer pin numbers against the symbol\u003C/h3>\n\u003Cp>Find the numbered terminal assignment in the applicable manufacturer document. In the CAD library, inspect the \u003Cstrong>pin numbers and electrical functions\u003C/strong>, not just the letters drawn near the symbol.\u003C/p>\n\u003Cp>For the fictional example, a reviewer would check that symbol pin 1 is the collector, pin 2 is the base, and pin 3 is the emitter. Then check the schematic connections and net names at those pins. If a symbol uses different numbers, the part-to-symbol relationship must be corrected or independently justified before release.\u003C/p>\n\u003Cp>Record the evidence against the schematic revision. A library name that resembles the MPN is not evidence that the symbol was built correctly.\u003C/p>\n\u003Ch3>Check symbol numbers against PCB pad numbers and nets\u003C/h3>\n\u003Cp>Inspect the symbol-to-footprint association and the PCB design data. Confirm that the footprint pads have the intended numbers and that each numbered pad carries the same net as the corresponding schematic pin.\u003C/p>\n\u003Cp>Use the exported netlist or an equivalent design report to help reconcile the schematic and layout. A connectivity check can catch a mismatch between design records, but it cannot independently establish what a pad number means on the manufactured component. That still requires the manufacturer’s numbered package drawing and a review of the footprint.\u003C/p>\n\u003Cp>Keep the reference designator consistent across the BOM, schematic, layout, and assembly documentation. Otherwise, a correct mapping may be applied to the wrong component.\u003C/p>\n\u003Ch3>Check the physical footprint independently\u003C/h3>\n\u003Cp>Compare the current manufacturer package drawing with the actual library footprint. Trace each numbered physical lead to its intended numbered pad using the drawing’s stated views and dimensions. Review hole and pad geometry, lead form, body clearance, and any mechanical constraints relevant to the design.\u003C/p>\n\u003Cp>Pay particular attention to library markings: a pad-number label, silkscreen feature, or assembly outline is useful only if it has been verified against the specific part and drawing. Do not assume a familiar outline proves the pad numbering.\u003C/p>\n\u003Cp>If the manufacturer drawing’s view is unclear, or the CAD footprint cannot be reconciled with it, hold the item for engineering review. A logically consistent netlist does not resolve a physical ambiguity.\u003C/p>\n\u003Ch3>Check assembly side and orientation separately\u003C/h3>\n\u003Cp>The assembly record must identify the intended board side and give an unambiguous, verified orientation for the exact part and footprint. Review the board and component views stated on the assembly drawing, along with the reference designator and relevant orientation features.\u003C/p>\n\u003Cp>If a placement file is used, reconcile its side, rotation convention, coordinate origin, and component reference with the assembly drawing and the actual footprint. A coordinate or rotation value is meaningful only in the convention used by that file and the receiving process.\u003C/p>\n\u003Cp>A TO-92 component is not necessarily an SMT component, and its example here does not imply a pick-and-place process. Where the selected process uses insertion or another method, provide and check the appropriate assembly instructions instead of assuming an SMT placement file is required.\u003C/p>\n\u003Ch2>Verification matrix: evidence and release decision\u003C/h2>\n\u003Cp>Use this matrix to capture the result of the review rather than treating a visual check as blanket approval.\u003C/p>\n\u003Ctable>\n\u003Cthead>\n\u003Ctr>\n\u003Cth>Check\u003C/th>\n\u003Cth>Evidence to reconcile\u003C/th>\n\u003Cth>Hold or action if it fails\u003C/th>\n\u003C/tr>\n\u003C/thead>\n\u003Ctbody>\u003Ctr>\n\u003Ctd>Part identity\u003C/td>\n\u003Ctd>Approved BOM, manufacturer, full MPN, package and ordering details\u003C/td>\n\u003Ctd>Hold procurement or assembly until the intended part is resolved\u003C/td>\n\u003C/tr>\n\u003Ctr>\n\u003Ctd>Source applicability\u003C/td>\n\u003Ctd>Current manufacturer datasheet and package drawing for that MPN; recorded revision\u003C/td>\n\u003Ctd>Obtain the applicable document; do not promote a historical source to current status\u003C/td>\n\u003C/tr>\n\u003Ctr>\n\u003Ctd>Terminal assignment\u003C/td>\n\u003Ctd>Manufacturer pin numbers and functions against symbol pin numbers\u003C/td>\n\u003Ctd>Correct the symbol or part association and re-review affected design data\u003C/td>\n\u003C/tr>\n\u003Ctr>\n\u003Ctd>Logical connectivity\u003C/td>\n\u003Ctd>Schematic pins, net names, PCB pad numbers, and netlist\u003C/td>\n\u003Ctd>Resolve mismatches and regenerate controlled outputs as needed\u003C/td>\n\u003C/tr>\n\u003Ctr>\n\u003Ctd>Physical fit and numbering\u003C/td>\n\u003Ctd>Manufacturer package views and lead numbers against footprint geometry and pad numbers\u003C/td>\n\u003Ctd>Hold the footprint; correct it or obtain documented engineering resolution\u003C/td>\n\u003C/tr>\n\u003Ctr>\n\u003Ctd>Assembly direction\u003C/td>\n\u003Ctd>Assembly side, stated drawing view, orientation features, and process data where applicable\u003C/td>\n\u003Ctd>Clarify the controlled assembly instructions before build\u003C/td>\n\u003C/tr>\n\u003Ctr>\n\u003Ctd>Electrical suitability\u003C/td>\n\u003Ctd>Actual circuit requirements against the exact part’s current specifications and thermal conditions\u003C/td>\n\u003Ctd>Refer to the design authority; pinout agreement is not electrical approval\u003C/td>\n\u003C/tr>\n\u003Ctr>\n\u003Ctd>Supply and change status\u003C/td>\n\u003Ctd>Traceable source, lifecycle information, and relevant manufacturer notices\u003C/td>\n\u003Ctd>Escalate supply uncertainty; do not infer availability from an old datasheet\u003C/td>\n\u003C/tr>\n\u003C/tbody>\u003C/table>\n\u003Cp>The design authority should determine the disposition of technical discrepancies. Procurement can investigate sourcing, and the assembly team can flag document or orientation conflicts, but neither a purchasing match nor a manufacturable-looking layout replaces design approval.\u003C/p>\n\u003Ch2>Exceptions: stop, investigate, then document the decision\u003C/h2>\n\u003Cp>\u003Cstrong>The BOM says only “2N2222.”\u003C/strong> Ask the design owner to identify the manufacturer and full MPN. Do not select a part solely from the family name and silently treat it as approved.\u003C/p>\n\u003Cp>\u003Cstrong>The schematic and PCB agree, but the footprint’s physical numbering is uncertain.\u003C/strong> Hold release until the lead-to-pad mapping is reconciled with the applicable manufacturer drawing. Agreement between CAD files can reproduce the same library error.\u003C/p>\n\u003Cp>\u003Cstrong>The assembly drawing and process file disagree.\u003C/strong> Stop and reconcile the controlled documents. Establish which revision and viewing convention are intended; do not choose an orientation by appearance alone.\u003C/p>\n\u003Cp>\u003Cstrong>The specified part is unavailable or a different ordering variant is proposed.\u003C/strong> Treat the change as a substitution request, even if the new part has a familiar family name or package label. Compare pin functions and physical fit as well as electrical behavior, thermal conditions, lead form, supply traceability, and any project-specific requirements.\u003C/p>\n\u003Cp>The design authority must approve the technical change, and the customer must approve it where the project requires. Update affected BOM, CAD, and assembly records under revision control before using the changed part. An assembly team should not make an undocumented substitution.\u003C/p>\n\u003Ch2>RFQ and release checklist\u003C/h2>\n\u003Cp>Before submitting an \u003Ca href=\"/en/quote/\">RFQ\u003C/a>, or releasing the design for assembly, prepare the applicable records:\u003C/p>\n\u003Cul>\n\u003Cli>\u003Cinput disabled=\"\" type=\"checkbox\"> Identify each transistor by reference designator, manufacturer, full MPN, and package in the BOM.\u003C/li>\n\u003Cli>\u003Cinput disabled=\"\" type=\"checkbox\"> Provide the applicable design revision and the current manufacturer document used for the pin and package review.\u003C/li>\n\u003Cli>\u003Cinput disabled=\"\" type=\"checkbox\"> Verify numbered device pins against symbol pins, then symbol nets against numbered PCB pads.\u003C/li>\n\u003Cli>\u003Cinput disabled=\"\" type=\"checkbox\"> Review the physical footprint against the manufacturer package drawing, including lead form and mechanical fit.\u003C/li>\n\u003Cli>\u003Cinput disabled=\"\" type=\"checkbox\"> Provide an assembly drawing that identifies board side and verified orientation.\u003C/li>\n\u003Cli>\u003Cinput disabled=\"\" type=\"checkbox\"> Include placement data only where appropriate to the chosen process, and reconcile it with the assembly drawing.\u003C/li>\n\u003Cli>\u003Cinput disabled=\"\" type=\"checkbox\"> Identify unresolved supply questions and any proposed alternate as an exception—not an approved replacement.\u003C/li>\n\u003Cli>\u003Cinput disabled=\"\" type=\"checkbox\"> Record who owns design review, substitution approval, document updates, and any required customer authorization.\u003C/li>\n\u003Cli>\u003Cinput disabled=\"\" type=\"checkbox\"> Release a consistent set of BOM, design, and assembly revisions; retain the evidence behind the decision.\u003C/li>\n\u003C/ul>\n\u003Cp>To discuss the build, \u003Ca href=\"/en/quote/\">request a quote\u003C/a> and include the applicable records above, along with any unresolved questions. A quote request does not itself approve an unresolved pinout, footprint, or substitute.\u003C/p>\n\u003C!-- faq:start -->\n\n\u003Ch2>FAQ\u003C/h2>\n\u003Ch3>Is there one universal 2N2222 pinout?\u003C/h3>\n\u003Cp>No. Verify the numbered terminals for the exact manufacturer part and package using its applicable datasheet. A family name alone is not a reliable assembly instruction.\u003C/p>\n\u003Ch3>What does the historical P2N2222AG example establish?\u003C/h3>\n\u003Cp>The onsemi P2N2222A/D Rev. 7 source specifies collector on pin 1, base on pin 2, and emitter on pin 3 for the listed P2N2222AG in TO-92 CASE 29 STYLE 17. It does not establish current availability or a universal family mapping.\u003C/p>\n\u003Ch3>If the schematic and PCB net names match, is the footprint correct?\u003C/h3>\n\u003Cp>Not necessarily. Matching net names and numbers establish a logical relationship in the design records. The physical lead-to-pad mapping, geometry, and assembly orientation require separate verification.\u003C/p>\n\u003Ch3>Does a TO-92 transistor always need a pick-and-place file?\u003C/h3>\n\u003Cp>No. The necessary assembly instructions depend on the selected process. Use placement data where applicable, and otherwise provide suitable controlled instructions for the assembly method.\u003C/p>\n\u003Ch3>Who approves a substitute when the original part cannot be sourced?\u003C/h3>\n\u003Cp>The design authority approves the technical suitability, and the customer approves the change where required by the project. Procurement and assembly should communicate the issue, but should not silently replace the specified part.\u003C/p>\n\u003C!-- faq:end -->\n\u003Csection class=\"related-links\" aria-label=\"Related\">\u003Ch3>Related links\u003C/h3>\u003Cul>\u003Cli>\u003Ca href=\"/en/blog/circuit-board-components/\">Circuit Board Components: Common PCB Parts, What They Do and How to Identify Them\u003C/a>\u003C/li>\u003Cli>\u003Ca href=\"/en/blog/pcb-component-substitution-approval/\">PCB Component Substitution: An Approval Checklist\u003C/a>\u003C/li>\u003Cli>\u003Ca href=\"/en/blog/pick-and-place-file-checklist/\">Pick-and-Place Files: CPL Fields, Rotation and BOM Matching Checks\u003C/a>\u003C/li>\u003Cli>\u003Ca href=\"/en/quote/\">RFQ\u003C/a>\u003C/li>\u003C/ul>\u003C/section>",[14,17,20,23,26],{"question":15,"answer":16,"answerText":16},"Is there one universal 2N2222 pinout?","No. Verify the numbered terminals for the exact manufacturer part and package using its applicable datasheet. A family name alone is not a reliable assembly instruction.",{"question":18,"answer":19,"answerText":19},"What does the historical P2N2222AG example establish?","The onsemi P2N2222A/D Rev. 7 source specifies collector on pin 1, base on pin 2, and emitter on pin 3 for the listed P2N2222AG in TO-92 CASE 29 STYLE 17. It does not establish current availability or a universal family mapping.",{"question":21,"answer":22,"answerText":22},"If the schematic and PCB net names match, is the footprint correct?","Not necessarily. Matching net names and numbers establish a logical relationship in the design records. The physical lead-to-pad mapping, geometry, and assembly orientation require separate verification.",{"question":24,"answer":25,"answerText":25},"Does a TO-92 transistor always need a pick-and-place file?","No. The necessary assembly instructions depend on the selected process. Use placement data where applicable, and otherwise provide suitable controlled instructions for the assembly method.",{"question":27,"answer":28,"answerText":28},"Who approves a substitute when the original part cannot be sourced?","The design authority approves the technical suitability, and the customer approves the change where required by the project. Procurement and assembly should communicate the issue, but should not silently replace the specified part.",[30,31,32],"2N2222 pinout","transistor pinout","PCB assembly","2n2222-pinout-pcb-assembly","en",[34,36,37,38,39,40],"de","it","cn","fr","ru",{"blog":42,"breadcrumb":51},{"@context":43,"@type":44,"headline":4,"description":5,"image":8,"url":45,"datePublished":6,"dateModified":6,"timeRequired":11,"keywords":46,"articleSection":7,"author":47,"publisher":50},"https://schema.org","BlogPosting","https://hilpcb.com/en/blog/2n2222-pinout-pcb-assembly/","2N2222 pinout, transistor pinout, PCB assembly",{"@type":48,"name":49},"Organization","HILPCB",{"@type":48,"name":49},{"@context":43,"@type":52,"itemListElement":53},"BreadcrumbList",[54,59,63],{"@type":55,"position":56,"name":57,"item":58},"ListItem",1,"Home","https://hilpcb.com/",{"@type":55,"position":60,"name":61,"item":62},2,"Blog","https://hilpcb.com/en/blog/",{"@type":55,"position":64,"name":33,"item":45},3,1794483749814]