27C512-25-X - 512Kbit 64Kx8 UV EPROM 250ns | Fujitsu
MPN： 27C512-25-X ✗ 停產27C512-25-X 概覽
An EPROM (Erasable Programmable Read-Only Memory) is a non-volatile memory technology that retains programmed data without power and can be erased in bulk by exposure to ultraviolet light through a quartz window (in the UV variant) before reprogramming. Within the memory hierarchy, EPROMs sit between mask ROM and modern Flash memory, and the 27C512 became one of the most widely standardized 512 Kbit devices across the industry, with JEDEC pinout compatibility across manufacturers.
Key features include the 64K x 8 organization, 250 ns access speed grade (sufficient for mid-speed 8-bit and 16-bit microprocessor systems without wait states at moderate clock rates), CMOS technology for low standby power consumption (on the order of tens of microamperes typical in standby, per 27C512 family datasheets), and a single +5 V read-mode supply. Programming is performed at elevated voltage using standard EPROM programming algorithms.
Technically, the device uses CMOS memory cells arrayed as 65,536 bytes, address decoding across 15 address lines (A0-A14), and active-low chip enable (/CE) and output enable (/OE) controls supporting standby and read modes.
Typical applications include firmware storage in legacy industrial controllers, automotive ECUs, arcade and retro-computing boards, telecom line cards, and test equipment where original EPROMs must be maintained or replaced.
Design consideration: verify whether your board requires the UV-erase windowed package or an OTP variant, and confirm the access-time grade meets your microprocessor timing margin at temperature extremes.
This page synthesizes distributor sourcing data, drop-in cross-references, and practical design notes for this discontinued Fujitsu memory not found on any single manufacturer datasheet.
直接替換替代品，適用於 27C512-25-X — 相同封裝，腳位對腳位相容。需重新設計 PCB 的不同封裝零件不列入。
此系列的變體
與下列產品可直接替換的同系列型號： 27C512-25-X （相同外形與佔位） — 差異在於 Memory Type, Package, Erase Method, Organization, Technology.
27C512-20
✅ 直接替換聯絡詢價
查看資料表 →27C512-15FA
✅ 直接替換聯絡詢價
查看資料表 →27C512A-12I/SO
✅ 直接替換聯絡詢價
查看資料表 →W27C512
✅ 直接替換📋 參考替代品（不在目錄中）
M27C512
✅ 直接替換📋 參考替代品（不在目錄中）
AT27C512R
✅ 直接替換📋 參考替代品（不在目錄中）
TMS27C512
✅ 直接替換📋 參考替代品（不在目錄中）
27C512-25-X 最大額定值與電氣特性
| 記憶體容量 | 512 Kbit (64K x 8) |
| 組織 | 65,536 words x 8 bits |
| 記憶體類型 | UV EPROM |
| Access Time | 250 ns |
| Supply Voltage (Read) | 5 V +/- 10% |
| Technology | CMOS |
| 介面 | Parallel |
| Address Lines | 15 (A0-A14) |
| Data Lines | 8 (D0-D7), 3-state outputs |
| Control Signals | /CE (chip enable), /OE (output enable), /PGM (program) |
| 封裝 | 28-pin DIP (windowed ceramic or plastic OTP variant per suffix) |
| 安裝類型 | Through Hole |
| Pinout | JEDEC-approved 27C512 pinout |
| RoHS 狀態 | unknown (legacy non-RoHS-era part) |
27C512-25-X 腳位配置
| 腳位 1 | A15 — Address line 15 (highest-order address bit) |
| 腳位 2 | A12 — Address line 12 |
| 腳位 3 | A7 — Address line 7 |
| 腳位 4 | A6 — Address line 6 |
| 腳位 5 | A5 — Address line 5 |
| 腳位 6 | A4 — Address line 4 |
| 腳位 7 | A3 — Address line 3 |
| 腳位 8 | A2 — Address line 2 |
| 腳位 9 | A1 — Address line 1 |
| 腳位 10 | A0 — Address line 0 (lowest-order address bit) |
| 腳位 11 | D0 — Data output 0 (3-state) |
| 腳位 12 | D1 — Data output 1 (3-state) |
| 腳位 13 | D2 — Data output 2 (3-state) |
| 腳位 14 | GND — Ground reference |
| 腳位 15 | D3 — Data output 3 (3-state) |
| 腳位 16 | D4 — Data output 4 (3-state) |
| 腳位 17 | D5 — Data output 5 (3-state) |
| 腳位 18 | D6 — Data output 6 (3-state) |
| 腳位 19 | D7 — Data output 7 (3-state, MSB) |
| 腳位 20 | /CE — Chip enable (active low); device select and standby control |
| 腳位 21 | A10 — Address line 10 |
| 腳位 22 | /OE — Output enable (active low); gates data outputs |
| 腳位 23 | A11 — Address line 11 |
| 腳位 24 | A9 — Address line 9; also VPP input in program mode on some variants |
| 腳位 25 | A8 — Address line 8 |
| 腳位 26 | A13 — Address line 13 |
| 腳位 27 | A14 — Address line 14 |
| 腳位 28 | VCC — +5 V power supply |
典型應用
27C512-25-X 適用於 6 應用s: Legacy Industrial Controller Firmware Storage, Retro Computing and Arcade Board Restoration, Automotive ECU and Engine Management Repair, Telecom Line Card and Network Equipment Maintenance, Test and Measurement Instrument Firmware, Embedded Systems Education and Prototyping.
Legacy Industrial Controller Firmware Storage
The 27C512-25-X stores boot and application firmware in PLCs, motor drives, and process controllers designed in the late 1980s through 1990s. Its 64K x 8 organization matches the 16-bit address space of popular 8-bit CPUs (Z80, 8051, 68HC11), and the 250 ns access time is adequate for clock rates up to roughly 8-12 MHz without wait states. The device's non-volatile storage retains program code during power loss, while the UV-erase capability permits field firmware updates by swapping pre-programmed devices. For sustaining these systems, JEDEC-pinout substitutes like W27C512 or M27C512 allow repair without PCB redesign.
推薦
Retro Computing and Arcade Board Restoration
Vintage computers, game consoles, and arcade PCBs rely on 27C512 EPROMs for game code and character ROMs. The 27C512-25-X's JEDEC 28-pin pinout and 5 V single-supply operation make it directly interchangeable with original Fujitsu, TI, or NEC devices in these boards. Restorers typically program new 27C512-type devices with verified ROM dumps; the 250 ns grade meets the timing of original mid-1980s processors (68000 systems at 8-12 MHz typically require 200-350 ns ROMs). EEPROM-type W27C512 is favored because it allows iterative reprogramming without a UV eraser lamp and 20-minute erase cycles.
推薦
Automotive ECU and Engine Management Repair
Many 1980s-1990s engine control units used a 27C512-class EPROM for fuel and ignition maps in a socketed DIP-28 position, allowing tuners and repair shops to reflash calibration data. The 27C512-25-X in a windowed ceramic package can be erased and reprogrammed for revised maps; its 250 ns access suits 8-bit ECUs (e.g., 68HC11-based systems). Note that automotive under-hood temperatures demand verification of the device's operating range, and vibration-prone sockets should be secured. EEPROM-type substitutes (W27C512) are popular because tuning iterations are faster without UV erase.
推薦
Telecom Line Card and Network Equipment Maintenance
Telecom rack equipment (channel banks, multiplexers, PBX cards) from the 1990s stored configuration and protocol firmware in 27C512 sockets. The 27C512-25-X's 5 V +/- 10% tolerance supports noisy backplane supplies common in telecom racks, and CMOS standby current minimizes rack-level power draw across hundreds of memory devices. Field service organizations maintain 27C512 stock to repair these long-lived systems; because access time requirements are modest, faster JEDEC-pinout equivalents can substitute freely. Socketed placement enables simple firmware revision swaps during maintenance windows.
推薦
Test and Measurement Instrument Firmware
Oscilloscopes, multimeters, and logic analyzers from the EPROM era stored self-test routines, calibration constants, and UI firmware in 27C512 devices. The 27C512-25-X provides 64 KB of code space, sufficient for compact instrument firmware, and its three-state data outputs share a CPU bus cleanly under /CE and /OE control. Repair technicians replacing failed EPROMs must preserve the exact firmware image; EEPROM-type drop-ins simplify the process. The 250 ns grade matches the moderate bus speeds of these instruments, and the device's non-volatility preserves calibration data through power cycles.
推薦
Embedded Systems Education and Prototyping
The 27C512 family remains valuable in university labs teaching microprocessor interfacing because its simple parallel interface (15 address lines, 8 data lines, /CE, /OE) transparently demonstrates memory bus timing, address decoding, and wait-state analysis. The 27C512-25-X's 250 ns timing allows students to compute and observe access-time margins directly on an oscilloscope. UV-erase workflow teaches non-volatile memory fundamentals before introducing Flash.socketed DIP-28 placement on breadboard-to-DIP adapters supports rapid experiments. Modern equivalents (AT27C512R OTP) reduce cost for student volume kits.
推薦
推薦產品摘要
工程參考資料，適用於 27C512-25-X — 比較、設計指引及合規資訊。
選型指南
與替代品比較
| 參數 | 本產品 | 27C512-20 | 27C512-15FA | W27C512 | M27C512 | AT27C512R | TMS27C512 | 27C512A-12I/SO |
|---|---|---|---|---|---|---|---|---|
| Package | DIP-28 | DIP-28 - same | DIP-28 - same | DIP-28 - same | DIP-28 - same | DIP-28 - same | DIP-28 - same | SOIC-28 (SMD footprint) |
| Brand | Fujitsu | Fujitsu | Fujitsu | Winbond | STMicroelectronics | Microchip Technology | Texas Instruments | Microchip Technology |
| Access Time | 250 ns | 200 ns | 150 ns | 45-120 ns | 100-200 ns | 45-90 ns | 100-200 ns | 120 ns |
| Organization | 64K x 8 | 64K x 8 | 64K x 8 | 64K x 8 | 64K x 8 | 64K x 8 | 64K x 8 | 64K x 8 |
| Erase Type | UV erase (windowed) / OTP per suffix | UV erase | UV erase | Electrical erase (EEPROM) | UV or OTP ranges | OTP only | UV erase | OTP |
| Supply Voltage | 5 V +/- 10% | 5 V +/- 10% | 5 V +/- 10% | 5 V | 5 V +/- 10% | 5 V +/- 10% | 5 V +/- 10% | 5 V +/- 10% |
| Lifecycle Status | Obsolete | Obsolete (legacy stock) | Obsolete (legacy stock) | Active/legacy production (Winbond) | Active (ST legacy line) | Active (Microchip) | Obsolete (legacy stock) | Active (Microchip) |
| Pinout Standard | JEDEC 27C512, 28-pin | JEDEC 27C512 - same | JEDEC 27C512 - same | JEDEC 27C512 - same | JEDEC 27C512 - same | JEDEC 27C512 - same | JEDEC 27C512 - same | JEDEC 27C512 (SOIC-28) |
主要差異化特點
- UV-erase reusability (對比AT27C512R)
- Cost of obsolescence trade-off (對比W27C512)
- Speed grade selection flexibility (對比27C512-20)
設計說明
Verify CPU timing margin against the 250 ns access time: total delay includes address setup, CE/OE access, and output float times plus bus capacitance derating (add roughly 5-10 ns per 100 pF of bus load). For CPUs above about 8 MHz at temperature extremes, prefer a 150-200 ns grade (27C512-15FA/27C512-20) or a modern 45-90 ns AT27C512R. Consult the CPU datasheet's memory read cycle timing rather than assuming the nominal access time applies at worst-case conditions.
Confirm technology type before programming: UV EPROMs (this device, M27C512, TMS27C512) require VPP and a UV eraser; the Winbond W27C512 is electrically erasable and uses a different programming algorithm. Using the wrong algorithm in an EPROM programmer can damage the device. Also distinguish windowed ceramic DIP from plastic OTP packages - a plastic package has no window and cannot be erased, despite sharing the same pinout and part family.
For socketed legacy repairs, use a low-profile machined-pin DIP-28 socket to ensure reliable contact over decades of service, and label the socketed firmware version on the board. Add 100 nF decoupling directly across VCC (pin 28) and GND (pin 14). Tie /CE and /OE appropriately: grounding /OE and decoding /CE gives fastest access; grounding /CE only increases standby power but is acceptable in single-memory systems.
合規資訊
Legacy pre-RoHS-era EPROM; Fujitsu no longer provides compliance declarations for this obsolete part. Verify with the distributing supplier for your specific stock lot.
