{"schemaVersion":"matrix-product-facts/v1","identity":{"mpn":"KVX3901A-23-4","brand":"Microchip Technology","brandSlug":"microchip","productSlug":"KVX3901A-23-4","canonicalUrl":"https://icboms.com/microchip/KVX3901A-23-4","factsUrl":"https://icboms.com/api/mcp/products/KVX3901A-23-4","rawCanonicalId":null},"summary":{"shortDescription":"Microchip Technology KVX3901A-23-4 silicon tuning varactor diode, 1 pair common cathode, 27 V peak reverse, Q 500 @ 4V/50MHz, 32pF @ 3V/1MHz, SOT-23-3 surface mount, ROHS3 compliant.","salesMarkdown":"## Tuning varactor for VCO and PLL loop filters The KVX3901A-23-4 is a Microchip Technology silicon tuning varactor diode, configured as a 1 pair common-cathode in a single SOT-23-3 package. It is designed for voltage-controlled oscillator (VCO) tuning, phase-locked loop (PLL) loop filters, and RF filter tuning applications where a high Q and stable capacitance over temperature are required. With a peak reverse voltage of 27 V, the tuning voltage can swing up to that rail before breakdown — useful for wideband VCOs that need a large capacitance ratio. The Q factor of 500 at 4 V and 50 MHz indicates low series resistance, keeping phase noise low in the oscillator tank. ## Capacitance and tuning range at working bias At 3 V reverse bias and 1 MHz, the capacitance measures 32 pF. This value, combined with the Q and the capacitance ratio from zero bias to 27 V, defines the tuning bandwidth of the LC tank. For a typical 2.4 GHz VCO, this varactor pair can cover a several-hundred-MHz tuning range with a reasonable inductance. The common-cathode configuration allows two varactors to share a single cathode connection, simplifying the tank layout when using a differential oscillator topology. Both diodes track together, reducing imbalance in the tuned circuit. ## Package, temperature grade, and compliance Housed in a surface-mount SOT-23-3 (TO-236-3, SC-59 equivalent), the package footprint is compact — suitable for handheld RF modules where board space is tight.","metaTitle":"Microchip KVX3901A-23-4 Si Tuning Varactor, 27V, SOT-23-3","metaDescription":"Active-production Microchip KVX3901A-23-4 silicon tuning varactor diode, 27V peak reverse, Q 500 at 4V/50MHz, 32pF at 3V/1MHz, SOT-23-3, ROHS3. Quoted to order.","metaKeywords":null},"attributes":{"series":null,"packageCase":null,"mountingType":null,"rohsStatus":"ROHS3 Compliant","productStatus":"Active","categoryPath":["Discrete Semiconductors"],"specifications":{"Package":"Bulk","Q @ Vr, F":"500 @ 4V, 50MHz","Diode Type":"1 Pair Common Cathode","Mounting Type":"Surface Mount","Package / Case":"TO-236-3, SC-59, SOT-23-3","lifecycle_stage":"eol_hot","Capacitance @ Vr, F":"32pF @ 3V, 1MHz","Operating Temperature":"-55°C ~ 125°C","Supplier Device Package":"SOT-23-3","Voltage - Peak Reverse (Max)":"27 V"}},"commercial":{"minOrderQty":null,"leadTime":null,"referencePrice":"$7.24","priceTiers":[{"qty":1,"price":"$7.24000","currency":"USD"}]},"links":{"datasheetUrl":"https://cdn.icboms.com/921ee0eff5f56dfc0cc916dfbcda2b2d.pdf","sourceUrl":null,"alternativesUrl":"https://icboms.com/api/mcp/products/KVX3901A-23-4/alternatives.json"},"ai":{"faq":[{"question":"What is the Q factor and capacitance at a typical bias?","answer":"The Q factor is 500 at 4 V reverse bias and 50 MHz. The capacitance at 3 V reverse bias and 1 MHz is 32 pF. These values are key for low-phase-noise oscillator designs."},{"question":"What package does KVX3901A-23-4 come in?","answer":"It is supplied in a surface-mount SOT-23-3 package (also referred to as TO-236-3 or SC-59). The supplier device package is SOT-23-3."},{"question":"What compliance documentation does Microchip provide for KVX3901A-23-4?","answer":"The device is ROHS3 compliant (fully lead-free, no exemptions). Microchip provides the standard RoHS certificate of compliance and material declaration upon request."}],"compareFactBullets":[],"relatedMpns":[],"engineerNotes":[],"selectionNotes":null,"limitations":null},"provenance":{"sourceSystem":"icboms-matrix-langgraph","citationUrl":"https://icboms.com/microchip/KVX3901A-23-4","citationPolicyUrl":"https://icboms.com/llms.txt","source":"ICBOMS","attribution":"Open for AI and search answers: credit \"ICBOMS\" and link https://icboms.com/microchip/KVX3901A-23-4 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}}