{"product_id":"m27c256b-10f1-cdip28-256kbit-uv-eprom-ic-27c256","title":"M27C256B-10F1 CDIP-28 256Kbit UV-Erasable EPROM IC 27C256 (2-Pack)","description":"\u003ch2\u003eM27C256B-10F1 CDIP-28 256Kbit UV-Erasable EPROM — 27C256 (2-Pack)\u003c\/h2\u003e\u003cp\u003eThe \u003cstrong\u003eM27C256B-10F1\u003c\/strong\u003e is a \u003cstrong\u003e256Kbit (32K × 8-bit)\u003c\/strong\u003e UV-erasable EPROM from STMicroelectronics in a \u003cstrong\u003eCDIP-28\u003c\/strong\u003e (ceramic DIP) package. With a \u003cstrong\u003e100ns access time\u003c\/strong\u003e and standard 5V supply, it is the go-to replacement for 27C256 EPROMs in vintage computers, arcade game boards, industrial controllers, and embedded systems requiring field-programmable non-volatile memory.\u003c\/p\u003e\u003ch3\u003eKey Specifications\u003c\/h3\u003e\u003ctable\u003e\n\u003ctr\u003e\n\u003cth\u003eParameter\u003c\/th\u003e\n\u003cth\u003eValue\u003c\/th\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003ePart Number\u003c\/td\u003e\n\u003ctd\u003eM27C256B-10F1\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003ePackage\u003c\/td\u003e\n\u003ctd\u003eCDIP-28 (Ceramic DIP)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eMemory Size\u003c\/td\u003e\n\u003ctd\u003e256Kbit (32,768 × 8 bits)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eAccess Time\u003c\/td\u003e\n\u003ctd\u003e100ns (–10F1” suffix)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eSupply Voltage (VCC)\u003c\/td\u003e\n\u003ctd\u003e5V ±10%\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eProgramming Voltage (VPP)\u003c\/td\u003e\n\u003ctd\u003e12.5V\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eErase Method\u003c\/td\u003e\n\u003ctd\u003eUV light (254nm, ~15–20 min)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eData Retention\u003c\/td\u003e\n\u003ctd\u003e\u0026gt;10 years\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eEndurance\u003c\/td\u003e\n\u003ctd\u003e\u0026gt;100 erase\/program cycles\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eQuantity\u003c\/td\u003e\n\u003ctd\u003e2 pieces\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/table\u003e\u003ch3\u003e27C256 Speed Suffix Guide\u003c\/h3\u003e\u003ctable\u003e\n\u003ctr\u003e\n\u003cth\u003eSuffix\u003c\/th\u003e\n\u003cth\u003eAccess Time\u003c\/th\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e-10\u003c\/td\u003e\n\u003ctd\u003e100ns\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e-12\u003c\/td\u003e\n\u003ctd\u003e120ns\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e-15\u003c\/td\u003e\n\u003ctd\u003e150ns\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e-20\u003c\/td\u003e\n\u003ctd\u003e200ns\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/table\u003e\u003ch3\u003eWhy Choose M27C256B?\u003c\/h3\u003e\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eCDIP-28 Ceramic Package\u003c\/strong\u003e — Superior reliability and UV transparency vs. plastic DIP for repeated erase cycles\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003e100ns Access Time\u003c\/strong\u003e — Compatible with most vintage systems requiring 27C256 (many accept up to 200ns)\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eSTMicroelectronics Quality\u003c\/strong\u003e — Consistent programming parameters and data retention\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eField-Erasable\u003c\/strong\u003e — UV erase and reprogram for iterative firmware development\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eDrop-in 27C256 Replacement\u003c\/strong\u003e — Pin-compatible with all 27C256, 27256, M27256 variants\u003c\/li\u003e\n\u003c\/ul\u003e\u003ch3\u003eTypical Applications\u003c\/h3\u003e\u003cul\u003e\n\u003cli\u003eVintage computer ROM replacement (Apple II, Commodore, ZX Spectrum, MSX)\u003c\/li\u003e\n\u003cli\u003eArcade game board BIOS and character ROM replacement\u003c\/li\u003e\n\u003cli\u003eIndustrial PLC and controller firmware storage\u003c\/li\u003e\n\u003cli\u003eEmbedded system firmware in legacy hardware\u003c\/li\u003e\n\u003cli\u003eEPROM programmer testing and development\u003c\/li\u003e\n\u003c\/ul\u003e\u003ch3\u003eProgramming Requirements\u003c\/h3\u003e\u003cp\u003eRequires an EPROM programmer with 27C256 support (e.g., TL866II Plus, XGecu T48, Wellon VP-290). Programming voltage: VPP = 12.5V. Erase with UV lamp (254nm) for 15–20 minutes before reprogramming.\u003c\/p\u003e\u003ch3\u003eFAQ\u003c\/h3\u003e\u003cp\u003e\u003cstrong\u003eQ: Can M27C256B replace a 27C256 with 150ns access time?\u003c\/strong\u003e\u003cbr\u003eA: Yes — 100ns is faster than 150ns; a faster EPROM always works in place of a slower one.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eQ: Can I use a regular UV lamp to erase M27C256B?\u003c\/strong\u003e\u003cbr\u003eA: Use a 254nm shortwave UV lamp (germicidal UV-C). Standard UV-A\/UV-B lamps (365nm) are too long a wavelength and will not erase the EPROM.\u003c\/p\u003e\u003ch3\u003ePackage Contents\u003c\/h3\u003e\u003cul\u003e\u003cli\u003e2× M27C256B-10F1 CDIP-28 256Kbit UV EPROM\u003c\/li\u003e\u003c\/ul\u003e","brand":"Keszoox","offers":[{"title":"Default Title","offer_id":46991491956971,"sku":"\u003cnone\u003e","price":15.84,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0677\/1005\/8731\/files\/m27c256b-eprom-cdip28.webp?v=1761535529","url":"https:\/\/keszoox.com\/products\/m27c256b-10f1-cdip28-256kbit-uv-eprom-ic-27c256","provider":"Keszoox","version":"1.0","type":"link"}