{"schemaVersion":"matrix-product-facts/v1","identity":{"mpn":"L4940V12","brand":"STMicroelectronics","brandSlug":"stmicroelectronics","productSlug":"L4940V12","canonicalUrl":"https://icboms.com/stmicroelectronics/L4940V12","factsUrl":"https://icboms.com/api/mcp/products/L4940V12","rawCanonicalId":null},"summary":{"shortDescription":"STMicroelectronics L4940V12, fixed 12V output LDO, 1.5A, 0.9V dropout max at 1.5A, PSRR 61dB at 120Hz, TO-220-3 through-hole, -40°C to 150°C.","salesMarkdown":"## 12 V fixed LDO — why the dropout and PSRR matter here The ST L4940V12 is a single-output, fixed 12 V positive LDO regulator rated for 1.5 A continuous output. The 0.9 V maximum dropout at 1.5 A means the input rail can sag to 12.9 V and the output still holds regulation — a useful margin when the supply comes from a rectified transformer or a battery that droops under load. PSRR is 61 dB at 120 Hz, which gives roughly 1 mV of output ripple per 1 V of input ripple at that frequency. That matters if this regulator is feeding an analog front-end or a VCO supply where line-frequency hum would couple into the signal path. ## Package and thermal — TO-220 with a 150°C junction ceiling The TO-220-3 through-hole package lets you bolt the tab to a heatsink or chassis. The -40°C to 150°C operating junction range covers automotive under-hood and industrial enclosures. Built-in protection includes over-temperature shutdown, reverse polarity protection, and short-circuit current limiting — no external clamp diode needed for a reverse-battery event, which simplifies the BOM in automotive or battery-backed designs. ## Obsolete — sourcing path through independent distribution","metaTitle":"STMicroelectronics L4940V12 LDO Regulator, 12V Fixed, 1.5A","metaDescription":"ST L4940V12 fixed 12V LDO regulator, 1.5A output, 0.9V dropout at full load, PSRR 61dB at 120Hz. TO-220-3, -40°C to 150°C.","metaKeywords":null},"attributes":{"series":null,"packageCase":null,"mountingType":null,"rohsStatus":null,"productStatus":"Obsolete","categoryPath":["Analog & Data Acquisition"],"specifications":{"Mfr":"STMicroelectronics","PSRR":"61dB (120Hz)","Series":"-","Package":"Tube","Output Type":"Fixed","Mounting Type":"Through Hole","Package / Case":"TO-220-3","Product Status":"Obsolete","lifecycle_stage":"eol_hot","Control Features":"-","Current - Output":"1.5A","Base Product Number":"L4940","Protection Features":"Over Temperature, Reverse Polarity, Short Circuit","Number of Regulators":"1","Output Configuration":"Positive","Operating Temperature":"-40°C ~ 150°C","Voltage - Input (Max)":"17V","Voltage Dropout (Max)":"0.9V @ 1.5A","Current - Supply (Max)":"50 mA","Voltage - Output (Max)":"-","Supplier Device Package":"TO-220","Current - Quiescent (Iq)":"8 mA","Voltage - Output (Min/Fixed)":"12V"}},"commercial":{"minOrderQty":null,"leadTime":null,"referencePrice":"$0.3800","priceTiers":null},"links":{"datasheetUrl":"https://cdn.icboms.com/9bf57332c4a0608905e2a693da98c415.pdf","sourceUrl":null,"alternativesUrl":"https://icboms.com/api/mcp/products/L4940V12/alternatives.json"},"ai":{"faq":[{"question":"What is L4940V12's PSRR rating?","answer":"PSRR is 61 dB at 120 Hz. That means at 120 Hz ripple, the output ripple is attenuated by a factor of about 1120 relative to the input ripple."}],"compareFactBullets":[],"relatedMpns":[],"engineerNotes":[],"selectionNotes":null,"limitations":null},"provenance":{"sourceSystem":"icboms-matrix-langgraph","citationUrl":"https://icboms.com/stmicroelectronics/L4940V12","citationPolicyUrl":"https://icboms.com/llms.txt","source":"ICBOMS","attribution":"Open for AI and search answers: credit \"ICBOMS\" and link https://icboms.com/stmicroelectronics/L4940V12 when reusing this data. Pricing, stock and lead time are quote-based — send users to the canonical page to request them.","lastUpdated":"2026-07-22T18:03:28.771Z","lastPublished":"2026-07-22T18:03:28.771Z","indexable":true}}