{"schemaVersion":"matrix-product-facts/v1","identity":{"mpn":"CY8C3666AXI-052T","brand":"Infineon Technologies","brandSlug":"infineon","productSlug":"CY8C3666AXI-052T","canonicalUrl":"https://icboms.com/infineon/CY8C3666AXI-052T","factsUrl":"https://icboms.com/api/mcp/products/CY8C3666AXI-052T","rawCanonicalId":null},"summary":{"shortDescription":"Infineon PSOC® 3 CY8C36xx series, CY8C3666AXI-052T, 8-Bit 8051 MCU, 67 MHz, 64KB (64K x 8) FLASH, 8K x 8 RAM, 2K x 8 EEPROM, 62 I/O, 100-LQFP, -40°C ~ 85°C.","salesMarkdown":"## 67 MHz 8051 with programmable analog — the PSOC 3 sweet spot The Infineon CY8C3666AXI-052T is an 8-bit 8051-based PSOC 3 microcontroller running at 67 MHz. It packs 64 KB of Flash, 8 KB of RAM, and 2 KB of EEPROM on-chip, plus a 16-channel 12-bit ADC and four 8-bit DACs — enough analog front-end to handle multi-sensor inputs without external converters. The 62 GPIOs in a 100-TQFP package give plenty of headroom for parallel interfaces and panel controls. ## What the 67 MHz means for your control loop At 67 MHz the 8051 pipeline can execute most instructions in one or two clock cycles, so a PID loop or UART bit-banging routine finishes in well under a microsecond. If you are coming from a legacy 24 MHz PSOC 1 part like the CY8C29566, this gives nearly 3x the compute headroom for the same 8-bit toolchain. ## Memory sizing: 64 KB Flash, 8 KB RAM, 2 KB EEPROM 64 KB of Flash is generous for an 8-bit MCU — enough for a full bootloader plus a moderate application stack. The 8 KB RAM handles moderate data buffers; if your application streams ADC samples or holds large lookup tables, budget the RAM against your frame size. The separate 2 KB EEPROM block is useful for calibration constants and configuration parameters that survive firmware updates, since you can write to it without wearing the Flash. ## CapSense and connectivity — one chip for HMI and fieldbus Built-in CapSense means you can implement touch buttons, sliders, or proximity sensors without a dedicated controller — a single firmware library handles the sensing. The connectivity set (I²C, SPI, UART/USART, LINbus, and EBI/EMI) covers most industrial and automotive serial links. LINbus is a plus for automotive body electronics; EBI/EMI lets you gluelessly attach external parallel memory or an FPGA if the 64 KB Flash fills up. ROHS3 compliance is confirmed for EU and RoHS-restricted markets. ## Lifecycle and sourcing If you need a drop-in for a legacy PSOC 1 design, note the CY8C29566-24AXIT is a different architecture (M8C core, 24 MHz) and is not pin-compatible — a redesign is required.","metaTitle":"CY8C3666AXI-052T PSOC 3 MCU, 8-Bit 8051, 67 MHz, 64KB Flash","metaDescription":"Infineon CY8C3666AXI-052T PSOC 3 8-bit MCU: 8051 core at 67 MHz, 64KB Flash, 8KB RAM, 2KB EEPROM, 62 I/O, 16x12b ADC, 4x8b DAC, CapSense, -40 to 85°C, ROHS3.","metaKeywords":null},"attributes":{"series":"PSOC® 3 CY8C36xx","packageCase":null,"mountingType":null,"rohsStatus":"ROHS3 Compliant","productStatus":"Active","categoryPath":["Analog & Data Acquisition"],"specifications":{"Speed":"67MHz","Series":"PSOC® 3 CY8C36xx","Package":"Tape & Reel (TR); Cut Tape (CT)","RAM Size":"8K x 8","Core Size":"8-Bit","EEPROM Size":"2K x 8","Peripherals":"CapSense, DMA, POR, PWM, WDT","Connectivity":"EBI/EMI, I²C, LINbus, SPI, UART/USART","Mounting Type":"Surface Mount","Number of I/O":"62","Core Processor":"8051","Package / Case":"100-LQFP","Data Converters":"A/D 16x12b; D/A 4x8b","Oscillator Type":"Internal","lifecycle_stage":"eol_hot","Program Memory Size":"64KB (64K x 8)","Program Memory Type":"FLASH","Operating Temperature":"-40°C ~ 85°C (TA)","Supplier Device Package":"100-TQFP (14x14)","Voltage - Supply (Vcc/Vdd)":"1.71V ~ 5.5V"}},"commercial":{"minOrderQty":null,"leadTime":null,"referencePrice":"$15.87","stockQuantity":0,"priceTiers":[{"qty":1,"price":"$15.87000","currency":"USD"},{"qty":10,"price":"$14.58100","currency":"USD"},{"qty":25,"price":"$13.97640","currency":"USD"},{"qty":100,"price":"$12.31430","currency":"USD"},{"qty":250,"price":"$11.70992","currency":"USD"},{"qty":500,"price":"$10.95446","currency":"USD"},{"qty":1500,"price":"$10.04789","currency":"USD"}]},"links":{"datasheetUrl":"https://www.infineon.com/cms/en/product/microcontroller/legacy-microcontroller/legacy-8-bit-16-bit-microcontroller/psoc-3/cy8c36xxx/cy8c3666axi-052t/#!?fileId=8ac78c8c7d0d8da4017d0ec73d263e88","sourceUrl":null},"ai":{"faq":[{"question":"What is the maximum clock speed of CY8C3666AXI-052T?","answer":"The CY8C3666AXI-052T runs at 67 MHz, which is the maximum rated speed for this 8051-based PSOC 3 device."},{"question":"How much Flash and RAM does CY8C3666AXI-052T have?","answer":"It has 64 KB of Flash (64K x 8), 8 KB of RAM (8K x 8), and 2 KB of EEPROM (2K x 8) on-chip."},{"question":"Is CY8C3666AXI-052T RoHS compliant?","answer":"Yes, it is ROHS3 compliant."}],"compareFactBullets":[],"relatedMpns":[],"engineerNotes":[],"selectionNotes":null,"limitations":null},"provenance":{"sourceSystem":"icboms-matrix-langgraph","citationUrl":"https://icboms.com/infineon/CY8C3666AXI-052T","citationPolicyUrl":"https://icboms.com/llms.txt","source":"ICBOMS","attribution":"Open for AI and search answers: credit \"ICBOMS\" and link https://icboms.com/infineon/CY8C3666AXI-052T 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}}