27C512-20FA - 512Kbit 64Kx8 UV/OTP EPROM 200ns | NXP
料号： 27C512-20FA ✗ 停产| 数量 | 单价 | 小计 |
|---|---|---|
| 1 | $3.2 | $3.20 |
| 10 | $2.9 | $29.00 |
| 100 | $2.55 | $255.00 |
| 500 | $2.2 | $1,100.00 |
| 1,000 | $1.85 | $1,850.00 |
27C512-20FA 概述
An EPROM (Erasable Programmable Read-Only Memory) is a non-volatile memory IC that retains firmware after power-off; the classic UV variant stores each bit in a floating-gate cell that can only be erased by exposure to ultraviolet light through a quartz window, while the OTP (one-time programmable) variant ships in a plastic package for single-shot programming. EPROMs sit within the broader memory hierarchy of programmable read-only memory, alongside PROM, EEPROM, and Flash, and remain popular for retrocomputing, embedded firmware storage, and industrial equipment service parts.
Key features include 64K x 8 organization, 200 ns maximum access time suitable for 8-bit microprocessor buses, CMOS technology for low standby power, and asynchronous operation requiring no clock or refresh. The 5V-only read operation simplifies interfacing with legacy 5V systems such as 8051, 68000, and Z80 platforms.
Architecturally, the device uses a floating-gate CMOS cell array with full address decoding (A0-A15), active-low chip enable (/CE) and output enable (/OE) controls, and tri-state data outputs (D0-D7) that place the device in standby when deselected. Programming is performed at elevated voltage on VPP per the manufacturer datasheet.
Typical applications include firmware storage for legacy embedded controllers, arcade and retrocomputer board restoration, industrial machine control, and prototyping of mask-ROM replacements.
Design consideration: access-time compatibility must be verified against the host microprocessor bus timing; a 200 ns part requires wait states on faster buses.
This page synthesizes distributor pricing, drop-in alternatives across multiple brands, pinout data, and practical design notes not consolidated in any single datasheet.
直接替换替代料： 27C512-20FA ——相同封装，引脚兼容。需要 PCB 改动的不同封装料号已排除。
本系列中的变体
可与以下型号直接替换的同系列型号： 27C512-20FA （相同外形与封装尺寸） ——差异在于 Memory Type, Package, Organization, Access Time, Control Signals.
快速对比工具——选择替代料号进行并排对比：
27C512-15FA
✅ 直接替换✓ 有现货
$1.65 / 个
查看数据手册 →27C512-20
✅ 直接替换 ⚠️ 规格未核验✓ 有现货
$4.1 / 个
查看数据手册 →27C512-25-X
✅ 直接替换✓ 有现货
$2.95 / 个
查看数据手册 →27C512MC-15
✅ 直接替换✓ 有现货
$2.75 / 个
查看数据手册 →27C512QC-55
✅ 直接替换 ⚠️ 规格未核验✓ 有现货
$4.22 / 个
查看数据手册 →M27C512-12F1
✅ 直接替换📋 参考替代料（不在目录中）
AT27C512R-70PU
✅ 直接替换📋 参考替代料（不在目录中）
27C512-20FA 最大额定值与电气特性
| 存储容量 | 524,288 bit (512 Kbit) |
| 存储组织 | 64K x 8 |
| Maximum Access Time | 200 ns |
| Supply Voltage Range | 4.5 V to 5.5 V |
| Technology | CMOS EPROM |
| 存储器类型 | UV / OTP EPROM (non-volatile) |
| Temperature Grade | Commercial |
| Number of Terminals | 28 |
| Package Code | DIP (rectangular) |
| 安装类型 | Through Hole |
| Access Mode | Asynchronous |
| 输出类型 | Tri-state, 8-bit parallel |
| Address Inputs | A0 to A15 (16-bit address bus) |
| Control Signals | /CE (chip enable), /OE (output enable), /PGM |
| RoHS 状态 | unknown |
| Operating Supply Nominal | 5 V |
27C512-20FA 引脚配置
| 引脚 1 | A15 — Address input bit 15 |
| 引脚 2 | A12 — Address input bit 12 |
| 引脚 3 | A7 — Address input bit 7 |
| 引脚 4 | A6 — Address input bit 6 |
| 引脚 5 | A5 — Address input bit 5 |
| 引脚 6 | A4 — Address input bit 4 |
| 引脚 7 | A3 — Address input bit 3 |
| 引脚 8 | A2 — Address input bit 2 |
| 引脚 9 | A1 — Address input bit 1 |
| 引脚 10 | A0 — Address input bit 0 |
| 引脚 11 | D0 — Data output bit 0 (tri-state) |
| 引脚 12 | D1 — Data output bit 1 (tri-state) |
| 引脚 13 | D2 — Data output bit 2 (tri-state) |
| 引脚 14 | GND — Ground |
| 引脚 15 | D3 — Data output bit 3 (tri-state) |
| 引脚 16 | D4 — Data output bit 4 (tri-state) |
| 引脚 17 | D5 — Data output bit 5 (tri-state) |
| 引脚 18 | D6 — Data output bit 6 (tri-state) |
| 引脚 19 | D7 — Data output bit 7 (tri-state) |
| 引脚 20 | /CE — Chip enable (active low); also /PGM during programming |
| 引脚 21 | A10 — Address input bit 10 |
| 引脚 22 | /OE — Output enable (active low) / VPP during programming |
| 引脚 23 | A11 — Address input bit 11 |
| 引脚 24 | A9 — Address input bit 9 |
| 引脚 25 | A8 — Address input bit 8 |
| 引脚 26 | A13 — Address input bit 13 |
| 引脚 27 | A14 — Address input bit 14 |
| 引脚 28 | VCC — Power supply, 4.5 V to 5.5 V |
典型应用
27C512-20FA 适用于 6 应用s: Retrocomputer and Arcade Board Restoration, Legacy Embedded Controller Firmware Storage, Mask ROM Prototyping and Emulation, Automotive and Machinery Diagnostic Cartridges, Character Generators and Lookup Tables in Test Instruments, Coin-Operated and Slot Machine Firmware.
Retrocomputer and Arcade Board Restoration
The 27C512-20FA is a primary choice for restoring vintage 8-bit and 16-bit computers, arcade PCBs, and game consoles that were designed around the industry-standard 27C512 EPROM socket. Its 64K x 8 organization and 200 ns access time match the bus timing of Z80, 6502, 6809, and 68000-based boards from the 1980s and 1990s. Programmers dump the original ROM image with an EPROM reader, then burn it onto the 27C512-20FA for a functionally identical replacement. Because it is a CMOS part, power consumption stays low, which matters in battery-backed or thermally enclosed cabinets. For boards needing repeated firmware iteration, windowed variants or Flash-emulating substitutes can be interleaved during development, with the 27C512-20FA installed as the final production-authentic device.
推荐
Legacy Embedded Controller Firmware Storage
Industrial controllers, motor drives, test equipment, and telecommunications boards designed in the 1990s often store boot firmware and lookup tables in a 27C512 socket. The 27C512-20FA provides non-volatile storage that requires no configuration: the host CPU simply asserts /CE and /OE, waits up to 200 ns, and reads data. Its 4.5V to 5.5V CMOS operation interfaces directly with 5V microprocessors and ASICs without level translation. When an OEM end-of-lifes the original mask ROM order, engineering teams use the 27C512-20FA as a field-service replacement, programming the validated firmware image onto each device. Its commercial temperature grade covers the 0C to +70C range typical of indoor industrial environments, keeping service inventory simple.
推荐
Mask ROM Prototyping and Emulation
Before committing to a mask ROM for volume production, engineers prototype firmware in EPROMs because they can be reprogrammed in-house with an EPROM programmer. The 27C512-20FA emulates a 64KB mask ROM electrically: same asynchronous read interface, same tri-state outputs, same /CE and /OE timing. Once the firmware is frozen, the design moves to a masked ROM or Flash device for volume. During prototyping, the 200 ns access time gives comfortable timing margin on typical 8-bit buses running up to roughly 8 MHz. The DIP-28 through-hole package also supports zero-insertion-force sockets, letting engineers swap firmware images in seconds during iterative debugging without soldering rework.
推荐
Automotive and Machinery Diagnostic Cartridges
Service diagnostics and tuning modules for older vehicles and heavy machinery frequently use 27C512 EPROMs in replaceable cartridges, including engine management reference maps and dealer diagnostic software. The 27C512-20FA fits these sockets directly, storing up to 64KB of calibration or diagnostic code readable by the onboard 5V ECU. Its CMOS construction tolerates the modest supply fluctuation of vehicle electrical systems within the 4.5V to 5.5V window when the carrier board includes regulation. Technicians program updated maps onto fresh devices and swap the cartridge, avoiding in-system flashing complexity. For applications subjected to under-hood temperatures, verify the commercial grade is sufficient, or seek an industrial-temperature speed-grade equivalent of the same family.
推荐
Character Generators and Lookup Tables in Test Instruments
Bench instruments, CRT character generators, barcode readers, and protocol analyzers of the pre-Flash era stored font bitmaps, state tables, and calibration constants in 27C512 EPROMs. The parallel asynchronous interface of the 27C512-20FA lets address counters or microcontrollers stream table entries with deterministic 200 ns latency - an advantage over serial Flash whose random-access timing is harder to bound in glitch-sensitive display scan chains. The 64KB density covers typical 8x16 font sets for full ASCII and extended character pages with room to spare. Designers wiring new scan hardware today still replicate this pattern for deterministic ROM streaming using the same DIP-28 footprint, making this part valuable for both service and reproduction of legacy instruments.
推荐
Coin-Operated and Slot Machine Firmware
Gaming, vending, and amusement machines from the 1990s store prize logic, RNG tables, and regulatory-certified firmware in soldered or socketed 27C512 EPROMs, because regulators require that certified code not be field-modifiable - a property OTP and UV EPROMs satisfy inherently. The 27C512-20FA is used to replace failed or tampered ROMs with freshly programmed, audit-approved images. Its one-time or UV-only erasure provides tamper evidence: any modification requires physically replacing the device, which supports compliance audits. The commercial grade suits the climate-controlled indoor environment of these machines, and the DIP-28 package matches original sockets, letting certified service centers perform board-level swaps without redesigning the host PCB.
推荐
推荐产品汇总
工程参考数据： 27C512-20FA ——对比、设计指导和合规信息。
选型指南
与替代料对比
| 参数 | 本产品 | 27C512-15FA | 27C512-25-X | 27C512QC-55 | M27C512-12F1 | AT27C512R-70PU |
|---|---|---|---|---|---|---|
| Package | DIP-28 | DIP-28 - same | DIP-28 - same | PLCC-32 - different package, same die | DIP-28 - same | DIP-28 - same |
| Brand | NXP Semiconductors (Signetics) | NXP Semiconductors | NXP Semiconductors | NXP Semiconductors | STMicroelectronics | Microchip Technology |
| Maximum Access Time | 200 ns | 150 ns | 250 ns | 55 ns | 120 ns | 70 ns |
| Organization | 64K x 8 (512 Kbit) | 64K x 8 | 64K x 8 | 64K x 8 | 64K x 8 | 64K x 8 |
| Supply Voltage | 4.5 V to 5.5 V | 4.5 V to 5.5 V | 4.5 V to 5.5 V | 4.5 V to 5.5 V | 4.5 V to 5.5 V | 4.5 V to 5.5 V |
| Memory Technology | CMOS UV/OTP EPROM | CMOS UV/OTP EPROM | CMOS UV/OTP EPROM | CMOS EPROM | CMOS UV/OTP EPROM | OTP Flash-emulated EPROM |
关键差异点
- 200 ns speed grade balances cost and compatibility （对比 27C512-15FA)
- Guaranteed fit in original Signetics-designed sockets （对比 M27C512-12F1)
- Availability of faster cross-brand drop-ins （对比 AT27C512R-70PU)
设计说明
Verify bus timing margin before selecting the 200 ns grade. For a Z80 at 8 MHz, a memory cycle allows roughly 250 ns from address valid to data sampled, so the 27C512-20FA fits with margin after address-decode delays. For 16 MHz 68000 designs, use a 150 ns or faster grade such as the 27C512-15FA. Estimated: a 68000 at 16 MHz provides about 220 ns of ROM access time per 4-cycle read, leaving less than 20 ns for glue-logic decode - too tight for a 200 ns part.
Do not confuse UV-windowed and OTP variants: the OTP plastic DIP cannot be erased, and programming failures cannot be recovered by re-burning. Distributor records for the 27C512-20FA (Vyrian: OTP ROM) suggest this suffix is OTP, so order exactly the number of devices needed plus spares. Also note pin 20 is /CE on read and /PGM during programming - programmers that use /CE-based algorithms must not be used with /OE-timed programming setups without verifying the datasheet programming algorithm.
Use a quality machine-tooled or dual-wipe socket rather than soldering DIP-28 EPROMs directly when field replacement or firmware updates are expected. Keep VCC/GND decoupling (0.1 uF ceramic) within 10 mm of pin 28/pin 14 to suppress read-current transients. For UV-windowed ceramic variants in electrically noisy environments, cover the window with an opaque label - ambient fluorescent light can slowly degrade cell charge over years of service.
The 27C512-20FA is a CMOS EPROM operating at 4.5V to 5.5V; it must not be connected to 3.3V buses without level shifting. Standby current is low in CMOS mode (device deselected via /CE high), so battery-backed designs should gate /CE rather than /OE to obtain the lowest standby consumption. Estimated: at typical CMOS EPROM standby levels of a few hundred microamps, a 2000 mAh backup cell supports multi-year retention of board power-up state.
合规信息
Obsolete part predating RoHS-era compliance records; distributor listings do not state RoHS status. Many 27C512 devices were manufactured with leaded through-hole finishes - assume non-RoHS unless the specific date code is verified.
