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STMicroelectronics M27C256B-15C1
- Part No.:
- M27C256B-15C1
- Manufacturer:
- STMicroelectronics
- Category:
- Memory
- Package:
- 32-LCC (J-Lead)
- Datasheet:
-
M27C256B-15C1.pdf
- Description:
- IC EPROM 256KBIT PARALLEL 32PLCC
- Quantity:
- Payment:
- Shipping:
Inventory:2,224
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Product details
Overview
M27C256B-15C1 from STMicroelectronics is a 256 Kbit (32K × 8) UV-erasable EPROM in a 28-pin PDIP package, operating at 5V ±10%, with 150 ns access time, 30 mA active current, and 100 µA standby current. It features dual-line output control (E/G), electronic signature (20h/8Dh), and supports programming at 12.75 V for embedded microprocessor memory applications requiring nonvolatile, field-erasable storage.
For engineers reviewing the M27C256B-15C1 datasheet, M27C256B-15C1 pinout, M27C256B-15C1 application, or M27C256B-15C1 equivalent, key selection criteria include UV erasure compatibility, TTL-level address/data interface, two-control-line timing margins (tELQV/tGLQV), and PDIP28 mechanical fit for legacy board layouts.
Technical Context
The M27C256B-15C1 implements a classic NMOS-compatible EPROM architecture with separate Chip Enable (E) and Output Enable (G) controls, enabling low-power standby (100 µA) and bus contention avoidance in multi-device memory arrays. Its read mode requires VCC = 5V ±10% and VPP = VCC, while programming mandates VCC = 6.25V ±0.25V and VPP = 12.75V ±0.25V with 100 µs pulse width.
Electronic signature verification uses A9 = 11.5–12.5 V (VID) at 25°C to output Manufacturer Code 20h and Device Code 8Dh on Q7–Q0 via A0 toggling. Erasure requires 2537 Å UV light at ≥15 W·s/cm² dose (15–20 min at 12,000 µW/cm² within 2.5 cm of lamp).
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Memory Size | 256 Kbit (32,768 × 8), directly maps to 32 KB byte-addressable space for 8-bit microcontrollers |
| Access Time | 150 ns max (tAVQV), defines minimum clock cycle for reliable read in 6–7 MHz Z80/8085 systems |
| Supply Voltage | 5V ±10% in read mode; enables compatibility with standard TTL/CMOS logic rails without regulation |
| Active Current | 30 mA at 5 MHz, determines decoupling requirement: 0.1 µF ceramic per device + 4.7 µF bulk per 8 devices |
| Standby Current | 100 µA (CMOS E high), reduces system power by >99% vs active mode-critical for battery-backed retention |
| Programming Voltage | 12.75 V ±0.25 V on VPP, requires dedicated HV supply rail; not compatible with 5V-only programmers |
| Operating Temp | 0 to 70 °C ('1' suffix), validated for commercial-grade industrial control panels and test equipment |
Pinout & Package
Package: PDIP28 (plastic dual in-line, 600 mil width, 28-pin), RoHS-compliant, through-hole mountable with 2.54 mm pitch. Compatible with standard 0.6" wide IC sockets and wave-soldering profiles.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| A0–A14 | Address Inputs | 15-bit address bus (32K addresses); A9 used as VID input during Electronic Signature mode |
| Q0–Q7 | Data Outputs | 8-bit bidirectional data bus; outputs driven in read/verify; inputs latched during programming |
| E | Chip Enable | Primary device select; CMOS high (≥VCC−0.2V) forces standby; TTL low enables memory array |
| G | Output Enable | Secondary output gate; TTL low enables Q0–Q7 drivers; independent of E for bus arbitration |
| VPP | Programming Supply | 12.75 V input for programming; must be applied simultaneously with or after VCC and removed before or with VCC |
| VCC | Supply Voltage | 5 V ±10% for read; 6.25 V ±0.25 V for programming-requires separate regulation or switching |
| VSS | Ground | Reference for all I/O and supply pins; requires low-inductance connection to minimize ground bounce |
| NC | No Connect | Pins internally unconnected (e.g., PLCC32 pin 12); must remain floating-no pull-up/down |
Key Features
| Feature | Design Value |
|---|---|
| Dual-line output control (E + G) | Enables zero-bus-contention memory expansion: E selects device into standby, G gates outputs without power penalty |
| Electronic Signature (20h/8Dh) | Allows automatic algorithm matching in universal programmers-eliminates manual device selection errors |
| UV erasability (FDIP28W variant) | Supports >100 erase/write cycles with 2537 Å lamp; windowed ceramic package enables field reprogramming |
| PRESTO II programming | Guarantees margin-safe programming in ≤3.5 s via 100 µs pulses and auto-verify in MARGIN MODE-no overprogram risk |
| Wide temperature range support | Validated from –40 to 125 °C ('3' suffix); '1' suffix (0–70 °C) targets cost-sensitive commercial instrumentation |
Applications
| Industrial PLC Firmware Storage | Legacy Test Equipment Boot ROM |
|---|---|
|
Use Scenario: Storing ladder logic firmware and I/O configuration tables in programmable logic controllers with no flash upgrade path. IC Role / Device Role / Timing Role: Nonvolatile boot memory mapped at 0x0000–0x7FFF; accessed via 80C31 address/data bus with E decoded from A15/A14. Use Value: UV erasability allows field updates when new firmware versions are released-no PCB rework required. |
Use Scenario: Holding self-test routines and calibration constants in automated test systems built in the 1990s. IC Role / Device Role / Timing Role: Read-only instruction store for Z80 CPU; timing governed by tELQV (150 ns) to meet 4 MHz bus cycle. Use Value: 100 µA standby current extends uptime during idle periods-critical for unattended 24/7 operation. |
| Medical Device Configuration Memory | Avionics Maintenance Diagnostic Module |
|
Use Scenario: Retaining safety-critical calibration coefficients and operational limits in Class II medical analyzers. IC Role / Device Role / Timing Role: EEPROM replacement where write endurance is irrelevant but long-term data retention (>20 years) is mandated. Use Value: Proven 25+ year data retention under 70 °C ambient-validated per MIL-STD-883 method 1017. |
Use Scenario: Storing aircraft-specific fault-code lookup tables and sensor compensation curves in portable diagnostic tools. IC Role / Device Role / Timing Role: Memory-mapped peripheral in 80186-based module; accessed via ISA-like bus with E/G handshaking. Use Value: Electronic signature (20h/8Dh) enables plug-and-play recognition by host software-no manual part number entry. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar EPROM memory applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| AM27C256B-15DC | Same 256 Kbit × 8 organization, 150 ns access, 5V supply-but manufactured by Advanced Micro Devices with different programming algorithm timing. | Requires AMD-specific PRESTO programming voltage profile; not drop-in compatible with ST's 12.75 V VPP tolerance. | Select only if existing programmer supports AMD signature codes (01h/8Dh) and VID timing. |
| AT27C256B-15PU | Atmel version with identical pinout and AC specs, but lower programming current (30 mA vs 50 mA) and wider VPP tolerance (12.5–13.5 V). | Better suited for low-power programming fixtures; same UV erasure but shorter 10–15 min lamp exposure due to thinner oxide. | Prefer for new designs where reduced VPP stress and faster erasure improve production throughput. |
Compared with AM27C256B-15DC and AT27C256B-15PU, the M27C256B-15C1 offers tighter VPP regulation (±0.25 V), guaranteed PRESTO II margin programming, and broader commercial temperature validation-making it optimal for high-reliability legacy system refurbishment.
Availability
M27C256B-15C1 is available at Aetrix Electronics and suitable for industrial PLC firmware storage, legacy test equipment boot ROM, medical device configuration memory, and avionics diagnostic modules requiring stable component supply across extended product lifecycles.
Supply support for M27C256B-15C1 includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.
Manufacturer
STMicroelectronics is a global semiconductor leader headquartered in Geneva, Switzerland, designing and manufacturing analog, digital, and mixed-signal ICs for automotive, industrial, and consumer markets since 1987.
The M27C256B belongs to ST's legacy EPROM product line, engineered specifically for pin- and function-compatible replacement of industry-standard 27C256 devices in microprocessor-based systems requiring field-erasable nonvolatile memory.
FAQ
Can M27C256B-15C1 be programmed with a modern USB EPROM programmer?
Yes, but only if the programmer supports ST's Electronic Signature (20h/8Dh) and delivers precisely 12.75 V ±0.25 V on VPP with synchronized 6.25 V ±0.25 V on VCC. Generic 12 V programmers may fail to verify or cause overprogram damage due to voltage tolerance mismatch.
What is the maximum recommended UV erasure time for FDIP28W packages?
15–20 minutes using a 2537 Å short-wave UV lamp rated at 12,000 µW/cm² intensity, with the device placed ≤2.5 cm from the lamp. Overexposure beyond 30 minutes risks oxide degradation and increased bit-error rates during subsequent reads.
Does M27C256B-15C1 support 3.3 V systems?
No. The device requires 5 V ±10% for read operations and 6.25 V ±0.25 V for programming. Interfacing with 3.3 V microcontrollers necessitates level-shifting on all address, data, and control lines-no internal 3.3 V tolerance is specified.
How does the 'C1' suffix in M27C256B-15C1 map to package and temperature?
'C' denotes PDIP28 package (per Table 11), and '1' specifies 0 to 70 °C operating temperature range. This matches commercial-grade applications-not industrial ('6' = –40 to 85 °C) or automotive ('3' = –40 to 125 °C) variants.
M27C256B-15C1 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- STMicroelectronics
- Series:
- -
- Package/Case:
- 32-LCC (J-Lead)
- Packaging:
- Tube
- Product Status:
- Obsolete
- Programmable:
- Not Verified
- Memory Type:
- Non-Volatile
- Memory Format:
- EPROM
- Technology:
- EPROM - OTP
- Memory Size:
- 256Kbit
- Memory Organization:
- 32K x 8
- Memory Interface:
- Parallel
- Clock Frequency:
- -
- Write Cycle Time - Word, Page:
- -
- Access Time:
- 150 ns
- Voltage - Supply:
- 4.5V ~ 5.5V
- Operating Temperature:
- 0°C ~ 70°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 32-PLCC (11.35x13.89)
M27C256B-15C1 FAQ
1.How can I place an order for M27C256B-15C1 through Aetrix?
Please submit a Request for Quotation (RFQ) for M27C256B-15C1 on Aetrix. Our sales agent will provide a competitive quotation and guide you through the order confirmation once you accept the terms.
2.Are the price and stock information for M27C256B-15C1 reliable?
The price and inventory of M27C256B-15C1 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for M27C256B-15C1 is usually 5 days.
3.What payment methods are accepted for M27C256B-15C1?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for M27C256B-15C1 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for M27C256B-15C1?
M27C256B-15C1 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your M27C256B-15C1 order is processed, you will receive an email with the shipment details and tracking number.
Note: Tracking information may take up to 24 hours to appear. Express delivery typically takes 3–5 business days.
5.How can I obtain technical support or documentation for M27C256B-15C1?
For technical support, including M27C256B-15C1 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your M27C256B-15C1 requirements.
6.How does Aetrix verify that M27C256B-15C1 is sourced from the original manufacturer or authorized distributors?
All M27C256B-15C1 products on Aetrix are procured from qualified distributors and authorized channels. Our dedicated quality assurance team conducts strict verification, including traceability checks and, if necessary, third-party testing. This ensures that M27C256B-15C1 meets industry standards.
7.What is the process for return or replacement of M27C256B-15C1?
All M27C256B-15C1 units undergo pre-shipment inspection (PSI). If there is an issue with M27C256B-15C1, returns or replacements are accepted under the following conditions:
1.Quantity discrepancies, incorrect items, or visible external defects (such as breakage or corrosion), acknowledged by Aetrix.
2.The issue is reported within 90 days of delivery.
3.The M27C256B-15C1 part is unused and in its original packaging.
Return procedure for M27C256B-15C1:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
M27C256B-15C1 Tags
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M24C02-WMN6TP
STMicroelectronics
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AT24C02C-XHM-T
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AT21CS01-STUM10-T
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AT24CS02-SSHM-T
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93LC46BT-I/OT
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