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M27C256B-10F1 CDIP-28 256Kbit UV-Erasable EPROM IC 27C256 (2-Pack)
M27C256B-10F1 CDIP-28 256Kbit UV-Erasable EPROM IC 27C256 (2-Pack)
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M27C256B-10F1 CDIP-28 256Kbit UV-Erasable EPROM — 27C256 (2-Pack)
The M27C256B-10F1 is a 256Kbit (32K × 8-bit) UV-erasable EPROM from STMicroelectronics in a CDIP-28 (ceramic DIP) package. With a 100ns access time 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.
Key Specifications
| Parameter | Value |
|---|---|
| Part Number | M27C256B-10F1 |
| Package | CDIP-28 (Ceramic DIP) |
| Memory Size | 256Kbit (32,768 × 8 bits) |
| Access Time | 100ns (–10F1” suffix) |
| Supply Voltage (VCC) | 5V ±10% |
| Programming Voltage (VPP) | 12.5V |
| Erase Method | UV light (254nm, ~15–20 min) |
| Data Retention | >10 years |
| Endurance | >100 erase/program cycles |
| Quantity | 2 pieces |
27C256 Speed Suffix Guide
| Suffix | Access Time |
|---|---|
| -10 | 100ns |
| -12 | 120ns |
| -15 | 150ns |
| -20 | 200ns |
Why Choose M27C256B?
- CDIP-28 Ceramic Package — Superior reliability and UV transparency vs. plastic DIP for repeated erase cycles
- 100ns Access Time — Compatible with most vintage systems requiring 27C256 (many accept up to 200ns)
- STMicroelectronics Quality — Consistent programming parameters and data retention
- Field-Erasable — UV erase and reprogram for iterative firmware development
- Drop-in 27C256 Replacement — Pin-compatible with all 27C256, 27256, M27256 variants
Typical Applications
- Vintage computer ROM replacement (Apple II, Commodore, ZX Spectrum, MSX)
- Arcade game board BIOS and character ROM replacement
- Industrial PLC and controller firmware storage
- Embedded system firmware in legacy hardware
- EPROM programmer testing and development
Programming Requirements
Requires 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.
FAQ
Q: Can M27C256B replace a 27C256 with 150ns access time?
A: Yes — 100ns is faster than 150ns; a faster EPROM always works in place of a slower one.
Q: Can I use a regular UV lamp to erase M27C256B?
A: 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.
Package Contents
- 2× M27C256B-10F1 CDIP-28 256Kbit UV EPROM
