{"schemaVersion":"matrix-product-facts/v1","identity":{"mpn":"LM2940CS-12","brand":"Texas Instruments","brandSlug":"texas-instruments","productSlug":"LM2940CS-12","canonicalUrl":"https://icboms.com/texas-instruments/LM2940CS-12","factsUrl":"https://icboms.com/api/mcp/products/LM2940CS-12","rawCanonicalId":null},"summary":{"shortDescription":"Texas Instruments LM2940CS-12, fixed 12V positive LDO regulator, 1A output, 0.8V dropout at 1A, 66dB PSRR at 120Hz, DDPAK/TO-263-3 surface mount, 0°C to 125°C.","salesMarkdown":"## 12V rail from a 13-14V bus — the dropout margin The LM2940CS-12 is a fixed 12V output positive LDO regulator from Texas Instruments, delivering up to 1A continuous current. Its 0.8V maximum dropout at full load means the input must stay above 12.8V to maintain regulation — a 13.2V nominal bus with 5% tolerance clears this, but a 12.6V rail during battery discharge will drop out. PSRR is specified at 66 dB at 120 Hz, which attenuates full-wave-rectified ripple by a factor of 2000. For a 1 Vpp ripple on the input, the output sees about 500 µVpp — clean enough for a 12-bit ADC reference rail or an op-amp supply, but not for a sensitive PLL or RF VCO without post-filtering. ## NRND — last-time-buy planning This means TI has flagged it for eventual discontinuation — new designs should migrate to an active alternative. Existing production can still be sourced through independent distribution on a quoted-to-order basis, but the window for last-time-buy commitments is narrowing. ## Protection set and temperature range Built-in protection covers over-current, over-temperature, reverse polarity, and short-circuit conditions — reducing the need for external clamp diodes or foldback circuits in ruggedized designs. ## Package and footprint — DDPAK/TO-263 Housed in a DDPAK/TO-263-3 surface-mount package (TO-263-4 with 3 leads plus tab), the exposed tab must be soldered to a sufficient copper plane for thermal dissipation. At 1A with 2V dropout, the die dissipates 2W — a 1-inch-square copper pad on a 2-layer board keeps the junction below 125°C in still air.","metaTitle":"LM2940CS-12 12V 1A LDO Regulator, NRND, DDPAK/TO-263","metaDescription":"Texas Instruments LM2940CS-12 fixed 12V output LDO, 1A, 0.8V dropout, 66dB PSRR at 120Hz.","metaKeywords":null},"attributes":{"series":null,"packageCase":null,"mountingType":null,"rohsStatus":null,"productStatus":"NRND","categoryPath":["Analog & Data Acquisition"],"specifications":{"Mfr":"Texas Instruments","PSRR":"66dB (120Hz)","Series":"-","Package":"Tube","Output Type":"Fixed","Mounting Type":"Surface Mount","Package / Case":"TO-263-4, D²Pak (3 Leads + Tab), TO-263AA","Product Status":"Not For New Designs","lifecycle_stage":"eol_hot","Control Features":"-","Current - Output":"1A","Base Product Number":"LM2940","Protection Features":"Over Current, Over Temperature, Reverse Polarity, Short Circuit","Number of Regulators":"1","Output Configuration":"Positive","Operating Temperature":"0°C~125°C","Voltage - Input (Max)":"26V","Voltage Dropout (Max)":"0.8V @ 1A","Current - Supply (Max)":"15 mA","Voltage - Output (Max)":"-","Supplier Device Package":"DDPAK/TO-263-3","Current - Quiescent (Iq)":"10 mA","Voltage - Output (Min/Fixed)":"12V"}},"commercial":{"minOrderQty":null,"leadTime":null,"referencePrice":"$3.1600","priceTiers":null},"links":{"datasheetUrl":"https://cdn.icboms.com/f1c4256f4019947c4206f2126daf8930.pdf","sourceUrl":null,"alternativesUrl":"https://icboms.com/api/mcp/products/LM2940CS-12/alternatives.json"},"ai":{"faq":[{"question":"Is LM2940CS-12 obsolete?","answer":"It is not yet formally discontinued, but TI advises against using it in new designs. Existing production can still be sourced, but the last-time-buy window is active."},{"question":"Can LM2940CS-12 replace LM2940CT-12?","answer":"The LM2940CT-12 is the through-hole TO-220 version of the same regulator. Electrically they are identical — same 12V fixed output, same 1A rating, same dropout and protection. The CS suffix is the surface-mount DDPAK variant; the CT suffix is the TO-220. Pinout differs: the TO-220 has the tab as output, while the DDPAK tab is ground. A direct board-level swap is not possible without layout changes."}],"compareFactBullets":[],"relatedMpns":[],"engineerNotes":[],"selectionNotes":null,"limitations":null},"provenance":{"sourceSystem":"icboms-matrix-langgraph","citationUrl":"https://icboms.com/texas-instruments/LM2940CS-12","citationPolicyUrl":"https://icboms.com/llms.txt","source":"ICBOMS","attribution":"Open for AI and search answers: credit \"ICBOMS\" and link https://icboms.com/texas-instruments/LM2940CS-12 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}}