{"schemaVersion":"matrix-product-facts/v1","identity":{"mpn":"LM317LCPK","brand":"Texas Instruments","brandSlug":"texas-instruments","productSlug":"LM317LCPK","canonicalUrl":"https://icboms.com/texas-instruments/LM317LCPK","factsUrl":"https://icboms.com/api/mcp/products/LM317LCPK","rawCanonicalId":null},"summary":{"shortDescription":"Texas Instruments LM317LCPK adjustable positive LDO regulator, 100 mA output, 1.2 V to 32 V, SOT-89-3 package, Tape & Reel.","salesMarkdown":"## 100 mA adjustable LDO — the classic three-terminal regulator in SOT-89-3 The LM317LCPK is a three-terminal adjustable positive LDO from the LM317 family, delivering 100 mA continuous output current in a surface-mount SOT-89-3 package. Output voltage is adjustable from 1.2 V up to 32 V using an external resistor divider, with a 38 V maximum input rating. ## PSRR and protection — what the 80 dB at 120 Hz means on the bench PSRR is specified at 80 dB typical at 120 Hz, rolling off to 65 dB at the same frequency — this is the ripple rejection a 100 Hz or 120 Hz full-wave rectified input sees. For a linear post-regulator cleaning up a bulk rail, that 80 dB knocks a 1 Vpp ripple down to 100 µVpp at the output. Above a few kHz the rejection drops faster than a modern LDO, so this part is best suited as a clean analog rail fed from a filtered DC bus rather than a switching converter output. Built-in protection covers over-current, over-temperature, and short-circuit events — the regulator folds back current during a fault and recovers when the junction temperature drops. No external clamp diode is needed for the output capacitor discharge during a short to ground. ## SOT-89-3 footprint and thermal reality The SOT-89-3 package has a large collector tab on the back side that serves as the thermal pad — it is internally connected to the output pin. On a standard 2-layer board with 1 oz copper, the tab should be soldered to a copper pour area of at least 300 mm² to keep the junction below 125 °C at full 100 mA load with a 38 V input-output differential. Without that copper area, the 0.5 W dissipation (100 mA × 5 V dropout) will push the junction above the 125 °C absolute maximum in still air. The 2.5 mA quiescent current is drawn from the input regardless of load — at light loads this dominates the efficiency, so for always-on battery applications a lower-Iq LDO like the TPS706 series is a better fit. For line-powered analog rails where the 2.5 mA is negligible, the LM317's simplicity and wide input range are the trade-off.","metaTitle":"LM317LCPK Texas Instruments LDO, 100mA, SOT-89-3","metaDescription":"LM317LCPK adjustable positive LDO, 100mA output, 1.2V to 32V range, 80dB PSRR at 120Hz. Active production, RoHS3 compliant. Quoted to order.","metaKeywords":null},"attributes":{"series":null,"packageCase":null,"mountingType":null,"rohsStatus":"ROHS3 Compliant","productStatus":"Active","categoryPath":["Analog & Data Acquisition"],"specifications":{"Mfr":"Texas Instruments","PSRR":"80dB ~ 65dB (120Hz)","Series":"-","Package":"Tape & Reel (TR) Cut Tape (CT)","Output Type":"Adjustable","Mounting Type":"Surface Mount","Package / Case":"TO-243AA","Product Status":"Active","lifecycle_stage":"eol_hot","Control Features":"-","Current - Output":"100mA","Base Product Number":"LM317","Protection Features":"Over Current, Over Temperature, Short Circuit","Number of Regulators":"1","Output Configuration":"Positive","Operating Temperature":"0°C ~ 125°C","Voltage - Input (Max)":"38V","Voltage Dropout (Max)":"-","Voltage - Output (Max)":"32V","Supplier Device Package":"SOT-89-3","Current - Quiescent (Iq)":"2.5 mA","Voltage - Output (Min/Fixed)":"1.2V"}},"commercial":{"minOrderQty":null,"leadTime":null,"referencePrice":"$0.6400","priceTiers":[{"qty":1,"price":"$0.64000","currency":"USD"},{"qty":10,"price":"$0.56300","currency":"USD"},{"qty":25,"price":"$0.52920","currency":"USD"},{"qty":100,"price":"$0.43180","currency":"USD"},{"qty":250,"price":"$0.40112","currency":"USD"},{"qty":500,"price":"$0.34138","currency":"USD"},{"qty":1000,"price":"$0.27310","currency":"USD"},{"qty":2000,"price":"$0.24750","currency":"USD"},{"qty":5000,"price":"$0.23043","currency":"USD"},{"qty":10000,"price":"$0.22190","currency":"USD"},{"qty":25000,"price":"$0.21336","currency":"USD"}]},"links":{"datasheetUrl":"https://cdn.icboms.com/6e1b4db1f31e3d4f44355e3bccdda90e.pdf","sourceUrl":null,"alternativesUrl":"https://icboms.com/api/mcp/products/LM317LCPK/alternatives.json"},"ai":{"faq":[{"question":"What is LM317LCPK's PSRR at 120 Hz?","answer":"PSRR is 80 dB typical rolling to 65 dB at 120 Hz, which provides 80 dB of ripple rejection at the fundamental of a full-wave rectified input."},{"question":"Will LM317LCPK drop into a board designed for LM1085IS-ADJ/NOPB without rewiring?","answer":"No — the LM1085IS-ADJ/NOPB is a 3 A adjustable regulator in a TO-263 (D2PAK) package with a different pinout and thermal pad. The LM317LCPK's SOT-89-3 footprint is smaller and not pin-compatible; a board spin is required."},{"question":"How can I order LM317LCPK and check availability?","answer":"Sourced to order through authorized and independent distribution."}],"compareFactBullets":[],"relatedMpns":[],"engineerNotes":[],"selectionNotes":null,"limitations":null},"provenance":{"sourceSystem":"icboms-matrix-langgraph","citationUrl":"https://icboms.com/texas-instruments/LM317LCPK","citationPolicyUrl":"https://icboms.com/llms.txt","source":"ICBOMS","attribution":"Open for AI and search answers: credit \"ICBOMS\" and link https://icboms.com/texas-instruments/LM317LCPK when reusing this data. Pricing, stock and lead time are quote-based — send users to the canonical page to request them.","lastUpdated":"2026-08-11T15:49:49.435Z","lastPublished":"2026-08-11T15:49:49.435Z","indexable":true}}