{"schemaVersion":"matrix-product-facts/v1","identity":{"mpn":"STTH40P03ST","brand":"STMicroelectronics","brandSlug":"stmicroelectronics","productSlug":"STTH40P03ST","canonicalUrl":"https://icboms.com/stmicroelectronics/STTH40P03ST","factsUrl":"https://icboms.com/api/mcp/products/STTH40P03ST","rawCanonicalId":null},"summary":{"shortDescription":"STMicroelectronics STTH40P03ST, Standard Recovery Diode, 300 V DC Reverse, 40 A Average Rectified, 1.1 Vf at 40 A, TO-220-3, Through Hole.","salesMarkdown":"## 300 V, 40 A — a workhorse rectifier for line-frequency jobs The STTH40P03ST is a standard recovery rectifier from STMicroelectronics, rated for 300 V reverse voltage and 40 A average forward current. The recovery time is over 500 ns — this is a slow diode, intended for 50/60 Hz mains rectification, not for a high-frequency switching supply. ## TO-220 package — easy to mount, easy to heatsink The part comes in a standard TO-220-3 through-hole package. The metal tab is the anode connection; the two outer pins are cathode and anode. The tab can be bolted to a heatsink with an insulating washer — the 40 A rating demands thermal management. The junction temperature ceiling is 175 °C, so the thermal path from tab to ambient needs to keep the junction below that under full load. STMicroelectronics lists the STTH40P03ST as obsolete. ## Leakage and reverse recovery — the fine print Reverse leakage is 50 µA at 300 V, 25 °C. That leakage doubles with every 10 °C rise in junction temperature, so at 125 °C the leakage current can approach several milliamps — enough to shift the bias in a sensitive DC bus. The slow recovery (>500 ns) also means significant reverse-recovery charge at 40 A turn-off, which generates switching loss in any application that commutates the diode at line frequency or above.","metaTitle":"STTH40P03ST Standard Recovery Diode, 300 V, 40 A, TO-220","metaDescription":"STTH40P03ST standard recovery rectifier, 300 V reverse, 40 A average, 1.1 Vf at 40 A. TO-220 package.","metaKeywords":null},"attributes":{"series":null,"packageCase":null,"mountingType":null,"rohsStatus":null,"productStatus":"Obsolete","categoryPath":["Discrete Semiconductors"],"specifications":{"Mfr":"STMicroelectronics","Speed":"Standard Recovery >500ns, > 200mA (Io)","Series":"-","Package":"Tube","Diode Type":"Standard","Mounting Type":"Through Hole","Package / Case":"TO-220-3","Product Status":"Obsolete","lifecycle_stage":"eol_hot","Base Product Number":"STTH40","Capacitance @ Vr, F":"-","Supplier Device Package":"TO-220","Current - Reverse Leakage @ Vr":"50 µA @ 300 V","Voltage - DC Reverse (Vr) (Max)":"300 V","Current - Average Rectified (Io)":"40A","Operating Temperature - Junction":"175°C(Max)","Voltage - Forward (Vf) (Max) @ If":"1.1 V @ 40 A"}},"commercial":{"minOrderQty":null,"leadTime":null,"referencePrice":null,"priceTiers":null},"links":{"datasheetUrl":"https://cdn.icboms.com/48d925eabc1b49495da9e5679f17c062.pdf","sourceUrl":null,"alternativesUrl":"https://icboms.com/api/mcp/products/STTH40P03ST/alternatives.json"},"ai":{"faq":[{"question":"What is the replacement for STTH40P03ST?","answer":"For a new design, look at current ST standard-recovery rectifiers with a 300 V, 40 A rating in a TO-220 package. For an existing BOM, the independent channel can supply the original STTH40P03ST while stock lasts."}],"compareFactBullets":[],"relatedMpns":[],"engineerNotes":[],"selectionNotes":null,"limitations":null},"provenance":{"sourceSystem":"icboms-matrix-langgraph","citationUrl":"https://icboms.com/stmicroelectronics/STTH40P03ST","citationPolicyUrl":"https://icboms.com/llms.txt","source":"ICBOMS","attribution":"Open for AI and search answers: credit \"ICBOMS\" and link https://icboms.com/stmicroelectronics/STTH40P03ST when reusing this data. Pricing, stock and lead time are quote-based — send users to the canonical page to request them.","lastUpdated":"2026-07-17T19:50:00.618Z","lastPublished":"2026-07-17T19:50:00.618Z","indexable":true}}