27C512-25-X - 512Kbit 64Kx8 UV EPROM 250ns | Fujitsu
Référence : 27C512-25-X ✗ Fin de vie| Qté | Prix unitaire | Total |
|---|---|---|
| 1 | $4.95 | $4,95 |
| 10 | $4.45 | $44,50 |
| 100 | $3.95 | $395,00 |
| 500 | $3.45 | $1 725,00 |
| 1 000 | $2.95 | $2 950,00 |
27C512-25-X Présentation
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.
Alternatives de remplacement direct pour 27C512-25-X — même boîtier, compatible broche à broche. Les références à boîtier différent nécessitant une retouche du PCB sont exclues.
Variantes de cette série
Modèles de la même série directement compatibles avec 27C512-25-X (même facteur de forme et même empreinte) — différant par Memory Type, Package, Erase Method, Organization, Technology.
Outil de comparaison rapide — sélectionnez des références alternatives pour une comparaison côte à côte :
27C512-20
✅ Remplacement direct✓ En stock
$4.1 / unité
Voir la fiche technique →27C512-15FA
✅ Remplacement direct✓ En stock
$1.65 / unité
Voir la fiche technique →27C512A-12I/SO
✅ Remplacement direct✓ En stock
$2.85 / unité
Voir la fiche technique →W27C512
✅ Remplacement direct📋 Alternative de référence (hors catalogue)
M27C512
✅ Remplacement direct📋 Alternative de référence (hors catalogue)
AT27C512R
✅ Remplacement direct📋 Alternative de référence (hors catalogue)
TMS27C512
✅ Remplacement direct📋 Alternative de référence (hors catalogue)
27C512-25-X Valeurs maximales et caractéristiques électriques
| Taille de mémoire | 512 Kbit (64K x 8) |
| Organisation de la mémoire | 65,536 words x 8 bits |
| Type de mémoire | UV EPROM |
| Access Time | 250 ns |
| Supply Voltage (Read) | 5 V +/- 10% |
| Technology | CMOS |
| Interface | Parallel |
| Address Lines | 15 (A0-A14) |
| Data Lines | 8 (D0-D7), 3-state outputs |
| Control Signals | /CE (chip enable), /OE (output enable), /PGM (program) |
| Boîtier | 28-pin DIP (windowed ceramic or plastic OTP variant per suffix) |
| Type de montage | Through Hole |
| Pinout | JEDEC-approved 27C512 pinout |
| Statut RoHS | unknown (legacy non-RoHS-era part) |
Configuration des broches de 27C512-25-X
| Broche 1 | A15 — Address line 15 (highest-order address bit) |
| Broche 2 | A12 — Address line 12 |
| Broche 3 | A7 — Address line 7 |
| Broche 4 | A6 — Address line 6 |
| Broche 5 | A5 — Address line 5 |
| Broche 6 | A4 — Address line 4 |
| Broche 7 | A3 — Address line 3 |
| Broche 8 | A2 — Address line 2 |
| Broche 9 | A1 — Address line 1 |
| Broche 10 | A0 — Address line 0 (lowest-order address bit) |
| Broche 11 | D0 — Data output 0 (3-state) |
| Broche 12 | D1 — Data output 1 (3-state) |
| Broche 13 | D2 — Data output 2 (3-state) |
| Broche 14 | GND — Ground reference |
| Broche 15 | D3 — Data output 3 (3-state) |
| Broche 16 | D4 — Data output 4 (3-state) |
| Broche 17 | D5 — Data output 5 (3-state) |
| Broche 18 | D6 — Data output 6 (3-state) |
| Broche 19 | D7 — Data output 7 (3-state, MSB) |
| Broche 20 | /CE — Chip enable (active low); device select and standby control |
| Broche 21 | A10 — Address line 10 |
| Broche 22 | /OE — Output enable (active low); gates data outputs |
| Broche 23 | A11 — Address line 11 |
| Broche 24 | A9 — Address line 9; also VPP input in program mode on some variants |
| Broche 25 | A8 — Address line 8 |
| Broche 26 | A13 — Address line 13 |
| Broche 27 | A14 — Address line 14 |
| Broche 28 | VCC — +5 V power supply |
Applications typiques
27C512-25-X convient pour 6 applications: 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.
Recommandé
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.
Recommandé
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.
Recommandé
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.
Recommandé
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.
Recommandé
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.
Recommandé
Récapitulatif des produits recommandés
Données de référence d'ingénierie pour 27C512-25-X — comparaison, recommandations de conception et informations de conformité.
Guide de sélection
Comparaison avec les alternatives
| Paramètre | Ce produit | 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) |
Principaux différenciateurs
- UV-erase reusability (vs AT27C512R)
- Cost of obsolescence trade-off (vs W27C512)
- Speed grade selection flexibility (vs 27C512-20)
Notes de conception
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.
Informations de conformité
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.
