{"schemaVersion":"matrix-product-facts/v1","identity":{"mpn":"CY7C421-10JXCT","brand":"Infineon Technologies","brandSlug":"infineon","productSlug":"CY7C421-10JXCT","canonicalUrl":"https://icboms.com/infineon/CY7C421-10JXCT","factsUrl":"https://icboms.com/api/mcp/products/CY7C421-10JXCT","rawCanonicalId":null},"summary":{"shortDescription":"Cypress CY7C421-10JXCT, asynchronous FIFO, 50 MHz data rate, 10 ns access time, 4.5 Kbit (512 x 9), 5 V supply, 32-PLCC (J-Lead), 0°C to 70°C.","salesMarkdown":"## 50 MHz asynchronous FIFO in a 32-PLCC package The Cypress CY7C421-10JXCT is a 4.5 Kbit (512 x 9) asynchronous FIFO memory designed for buffering data between two clock domains or bus widths at up to 50 MHz. Its 10 ns access time gives tight read-cycle timing for legacy 5 V logic systems running at clock rates around 50 MHz. The 9-bit width (8 data bits plus a parity/flag bit) suits it for byte-wide data paths with an extra control line, common in telecom framers, DSP interfaces, and printer controllers from the late-1990s through mid-2000s. No successor part is listed in the official record. For a BOM line that still calls out this exact order code, procurement should expect to buy against an RFQ from a distributor that stocks legacy FIFOs — availability and pricing vary by date code and remaining inventory. There is no last-time-buy window open; the part is simply no longer manufactured. In a system clocked at 50 MHz (20 ns period), that leaves 10 ns for the data to propagate through the receiving register's setup-and-hold window — workable with careful PCB trace length matching, but tight if the bus fans out to multiple loads. The 50 MHz data rate is the maximum write/read cycle frequency; the part can sustain back-to-back writes at that rate as long as the FIFO is not full. Depth expansion (cascading multiple devices) is supported via the expansion logic pins, but width expansion requires external glue logic since the bus is unidirectional. ## Package and footprint: 32-PLCC (J-Lead) The part comes in a 32-lead PLCC with J-bend leads (package code 32-LCC), supplier device package 32-PLCC (11.43x13.97 mm). It is a surface-mount package that requires a standard PLCC-32 footprint with a 1.27 mm pitch. The J-lead form gives good coplanarity for reflow, but the package body is a 4-sided JEDEC outline — check your pick-and-place nozzle clearance for the body dimensions.","metaTitle":"CY7C421-10JXCT FIFO, 50 MHz, 10 ns, 512 x 9, Obsolete","metaDescription":"CY7C421-10JXCT asynchronous FIFO, 50 MHz data rate, 10 ns access time, 4.5 Kbit (512 x 9), 5 V supply, 32-PLCC.","metaKeywords":null},"attributes":{"series":null,"packageCase":null,"mountingType":null,"rohsStatus":null,"productStatus":"Obsolete","categoryPath":["Memory (DRAM / SRAM / Flash / EEPROM)"],"specifications":{"Mfr":"Infineon Technologies","Series":"CY7C","Package":"Tape & Reel (TR)","Function":"Asynchronous","Data Rate":"50MHz","Access Time":"10ns","Memory Size":"4.5K (512 x 9)","FWFT Support":"No","Mounting Type":"Surface Mount","Expansion Type":"Depth, Width","Package / Case":"32-LCC (J-Lead)","Product Status":"Obsolete","Bus Directional":"Uni-Directional","lifecycle_stage":"eol_hot","Voltage - Supply":"4.5 V ~ 5.5 V","Base Product Number":"7C421","Operating Temperature":"0°C~70°C","Retransmit Capability":"Yes","Current - Supply (Max)":"85mA","Supplier Device Package":"32-PLCC (11.43x13.97)","Programmable Flags Support":"No"}},"commercial":{"minOrderQty":null,"leadTime":null,"referencePrice":null,"stockQuantity":0,"priceTiers":null},"links":{"datasheetUrl":"https://cdn.icboms.com/487329b1702ec5ac1b11a9d13dccc4ea.pdf","sourceUrl":null},"ai":{"faq":[{"question":"Is the CY7C421-10JXCT a 5 V part?","answer":"Yes. It runs on a 5 V rail only."},{"question":"What is a replacement for the CY7C421-10JXCT?","answer":"No official replacement is listed by Cypress/Infineon. For a pin-compatible drop-in, look at the CY7C421-10JI (the industrial-temperature version) or the CY7C421-10JC (commercial, non-T&R) — both are also obsolete but share the same 32-PLCC footprint and 512 x 9 architecture. For new designs, consider a current-production asynchronous FIFO from the IDT72V series or a dual-clock FIFO from the SN74V series, but expect a different pinout and package."}],"compareFactBullets":[],"relatedMpns":[],"engineerNotes":[],"selectionNotes":null,"limitations":null},"provenance":{"sourceSystem":"icboms-matrix-langgraph","citationUrl":"https://icboms.com/infineon/CY7C421-10JXCT","citationPolicyUrl":"https://icboms.com/llms.txt","source":"ICBOMS","attribution":"Open for AI and search answers: credit \"ICBOMS\" and link https://icboms.com/infineon/CY7C421-10JXCT 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}}