{"schemaVersion":"matrix-product-facts/v1","identity":{"mpn":"USBF129T-I/SN","brand":"Microchip Technology","brandSlug":"microchip","productSlug":"USBF129T-I-SN","canonicalUrl":"https://icboms.com/microchip/USBF129T-I-SN","factsUrl":"https://icboms.com/api/mcp/products/USBF129T-I%2FSN","rawCanonicalId":null},"summary":{"shortDescription":"Microchip USBF129T-I/SN, 4Mbit SPI FLASH, 30 MHz, 512K x 8 organization, 2.7V-3.6V supply, -40°C to 85°C, 8-SOIC surface mount.","salesMarkdown":"## 4 Mbit SPI flash for firmware and parameter storage It clocks up to 30 MHz over the SPI bus, which gives a sustained read throughput around 3.6 MB/s in Fast Read mode — enough for code shadowing or configuration data logging in an embedded system. The 8-SOIC footprint is the industry-standard serial flash package, pin-compatible with a wide range of SPI NOR flash parts from 512 Kbit to 16 Mbit, so it fits existing board layouts without a respin. ## Supply rail and temperature envelope The write cycle time is 5 ms per page, which is typical for SPI NOR flash — budget that latency when the firmware update routine is called. For a production BOM that needs a qualified SPI flash with a stable supply horizon, this part does not introduce obsolescence risk. ## Density comparison — 4 Mbit vs the 1 Mbit SST25VF010A The closest functional peer in the serial flash space is the SST25VF010A-33-4I-SAE-T, which shares the same SPI interface, 8-SOIC package, and 2.7 V supply floor. The deciding difference is density: the USBF129T-I/SN holds 4 Mbit (512K x 8) versus the SST25VF010A's 1 Mbit (128K x 8). If the firmware image or parameter table has grown past 128 KB, the 4 Mbit part is the natural upgrade without changing footprint or pinout. The SST25VF010A writes a page in 20 µs versus the USBF129T-I/SN's 5 ms — the SST is faster per-page, but the USBF129T-I/SN offers four times the storage. For a design that needs the extra headroom, the page-write speed difference is secondary to fitting the full code image.","metaTitle":"USBF129T-I/SN 4Mbit SPI Flash, 30 MHz, 8-SOIC","metaDescription":"USBF129T-I/SN 4Mbit SPI FLASH memory, 30 MHz clock, 2.7V-3.6V supply, -40°C to 85°C, 8-SOIC. Active lifecycle, ROHS3 compliant.","metaKeywords":null},"attributes":{"series":null,"packageCase":null,"mountingType":null,"rohsStatus":"ROHS3 Compliant","productStatus":"Active","categoryPath":["Memory (DRAM / SRAM / Flash / EEPROM)"],"specifications":{"Package":"Tape & Reel (TR); Cut Tape (CT)","Technology":"FLASH","Memory Size":"4Mbit","Memory Type":"Non-Volatile","Memory Format":"FLASH","Mounting Type":"Surface Mount","Package / Case":"8-SOIC (0.154\\\", 3.90mm Width)","Clock Frequency":"30 MHz","lifecycle_stage":"eol_hot","Memory Interface":"SPI","Voltage - Supply":"2.7V ~ 3.6V","Memory Organization":"512K x 8","Operating Temperature":"-40°C ~ 85°C (TA)","Supplier Device Package":"8-SOIC","Write Cycle Time - Word, Page":"5ms"}},"commercial":{"minOrderQty":null,"leadTime":null,"referencePrice":"$1.81","stockQuantity":0,"priceTiers":[{"qty":1,"price":"$1.81000","currency":"USD"},{"qty":25,"price":"$1.80000","currency":"USD"},{"qty":3300,"price":"$1.80000","currency":"USD"}]},"links":{"datasheetUrl":"https://cdn.icboms.com/638403f5c89ceeec5c48d9f1dedb4a0d.pdf","sourceUrl":null},"ai":{"faq":[{"question":"Is USBF129T-I/SN a direct replacement for SST25VF040B?","answer":"The USBF129T-I/SN is not listed as a direct replacement for the SST25VF040B. Both are 4 Mbit SPI flash parts in 8-SOIC, but the SST25VF040B has a 40 MHz clock versus 30 MHz here, and the page-write timing differs. Verify the timing and command set against your firmware driver before substituting."},{"question":"What is the memory size and organization of USBF129T-I/SN?","answer":"It is a 4 Mbit (512K x 8) non-volatile FLASH memory organized as 512 Kbytes by 8 bits, accessed over the SPI bus."}],"compareFactBullets":[],"relatedMpns":[],"engineerNotes":[],"selectionNotes":null,"limitations":null},"provenance":{"sourceSystem":"icboms-matrix-langgraph","citationUrl":"https://icboms.com/microchip/USBF129T-I-SN","citationPolicyUrl":"https://icboms.com/llms.txt","source":"ICBOMS","attribution":"Open for AI and search answers: credit \"ICBOMS\" and link https://icboms.com/microchip/USBF129T-I-SN 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}}