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STMicroelectronics M27W401-80B6

Name: M27W401-80B6
Brand: STMicroelectronics
SKU: M27W401-80B6
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: M27W401-80B6

Manufacturer:: STMicroelectronics

Category:: Memory

Package:: 32-DIP (0.600", 15.24mm)

Datasheet:: M27W401-80B6.pdf

Description:: IC EPROM 4MBIT PARALLEL 32DIP

Quantity:: RFQ Add To RFQ list

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Product details

Overview

M27W401-80B6 from STMicroelectronics is a 4 Mbit (512K × 8) low-voltage UV-erasable EPROM in PDIP32 package, operating from 2.7V to 3.6V with 80 ns access time at V_CC = 2.7V–3.6V, supporting microprocessor program/data storage across –40°C to +85°C industrial temperature range and featuring two-line output control (E/G) for bus contention avoidance in memory arrays.

For engineers reviewing the M27W401-80B6 datasheet, M27W401-80B6 pinout, M27W401-80B6 application, or M27W401-80B6 equivalent, this page delivers verified read timing, standby current (15 µA), programming voltage (12.75V on V_PP), electronic signature codes (20h/41h), and package-specific pin mapping for legacy system maintenance and replacement design.

Technical Context

The M27W401-80B6 implements a CMOS-based EPROM architecture with dual-control read enable (E = chip select, G = output gate), enabling independent device selection and output gating-critical for multi-chip memory systems. Its logic diagram confirms address decoding across A0–A18 (19-bit) and parallel 8-bit data I/O via Q0–Q7.

It supports four distinct operational modes: Read (E/VIL, G/VIL), Standby (E/VIH), Programming (E/pulsed VIL, G/VIH, V_PP = 12.75V), and Electronic Signature (A9 = 12V, V_PP/V_CC = 5V). Erasure requires UV exposure through the windowless PDIP32-B package only in UV-EPROM variants-this part number is OTP-compatible but not UV-erasable per ordering code B6.

Key Specifications

Parameter	Value and Actual Design Meaning
Memory Size	4 Mbit (524,288 × 8 bits); enables full firmware storage for 8-bit microcontrollers without external banking logic.
Read Access Time	80 ns at V_CC = 2.7V–3.6V; meets timing closure for 12.5 MHz bus clocks in legacy embedded systems.
Supply Voltage (Read)	2.7V–3.6V; allows direct interface with 3.3V logic families and battery-backed operation down to 2.7V.
Standby Current	15 µA max at V_CC ≤ 3.6V; reduces quiescent power in always-on industrial controllers.
Programming Voltage	V_PP = 12.75V ± 0.25V; requires dedicated high-voltage supply rail during programming, not derived from V_CC.
Electronic Signature	Manufacturer Code = 20h, Device Code = 41h; enables auto-recognition by universal programmers compatible with M27C4001.
Operating Temperature	–40°C to +85°C; qualified for industrial-grade deployment in motor drives and PLC modules.

Pinout & Package

Package: PDIP32 (B suffix), 600-mil plastic dual in-line, lead-free ECOPACK® compliant, through-hole mountable.

Pin/Terminal	Circuit Role	Design Meaning
A0–A18	Address Inputs	19-bit address bus; selects one of 524,288 bytes; TTL-compatible inputs support direct connection to 8051/68k address lines.
Q0–Q7	Data Outputs	8-bit bidirectional data bus in programming mode; outputs valid only when E and G both low in read mode.
E	Chip Enable	Primary device select; VIH places device in standby (15 µA), VIL enables internal circuitry for read/program operations.
G	Output Enable	Secondary output gate; controls Q0–Q7 tristate independently of E-prevents bus contention in multi-device configurations.
V_PP	Program Supply	12.75V input required only during programming; must be applied before/with V_CC; floating or incorrect voltage disables programming.
V_CC	Power Supply	2.7V–3.6V for read/standby; 6.25V ± 0.25V required during programming-separate voltage domain from read operation.
V_SS	Ground	Reference for all signals; requires local 0.1 µF ceramic decoupling capacitor per device per ST recommendation.

Key Features

Feature	Design Value
Two-line output control (E + G)	Eliminates bus contention in memory arrays by decoupling chip selection from output enable-no external bus transceivers needed.
Presto II programming algorithm	Guarantees margin-safe programming in ≤52.5 s using 100 µs pulses per byte; no over-programming required due to margin-mode verify at elevated V_CC.
Electronic signature (20h/41h)	Enables plug-and-play compatibility with M27C4001 programmers-no firmware update or configuration change needed for migration.
Low-voltage read operation	2.7V minimum V_CC supports battery-powered applications where 5V rails are unavailable or inefficient.
ECOPACK® compliance	Lead-free PDIP32 package meets RoHS and JEDEC JESD97 interconnect marking requirements-certified for industrial use.

Applications

Industrial PLC Firmware Storage

Legacy Automotive ECU Boot Memory

Use Scenario: Storing immutable boot code and calibration tables in programmable logic controllers deployed in factory automation cabinets.

IC Role / Device Role / Timing Role: Nonvolatile program memory mapped to CPU address space; accessed during cold start and watchdog reset recovery.

Use Value: 80 ns access time ensures deterministic boot within 100 ms; 15 µA standby current prevents battery drain during extended power-loss events.

Use Scenario: Holding engine control firmware in pre-OBD-II automotive ECUs where field reprogramming is unnecessary and cost sensitivity is high.

IC Role / Device Role / Timing Role: OTP EPROM used as mask-ROM replacement; programmed once at manufacturing and sealed against tampering.

Use Value: Pin compatibility with M27C4001 allows reuse of existing test fixtures and programming infrastructure-zero NRE redesign cost.

Medical Device Configuration ROM

Avionics System Initialization Memory

Use Scenario: Storing FDA-approved device configuration parameters and safety-critical startup sequences in Class II medical analyzers.

IC Role / Device Role / Timing Role: Read-only memory holding immutable calibration constants and regulatory-compliant boot checks.

Use Value: –40°C to +85°C rating ensures reliable operation inside temperature-controlled enclosures; ECOPACK® compliance satisfies medical RoHS requirements.

Use Scenario: Providing deterministic initialization vectors and flight-critical lookup tables in airborne navigation subsystems with long product lifecycles.

IC Role / Device Role / Timing Role: Fixed-function EPROM used in DO-254 Level A hardware; content verified at production and never modified in field.

Use Value: UV-erasable variant (FDIP32W) available for prototype validation; OTP version (PDIP32-B) deployed in certified hardware for permanent retention.

Equivalent & Alternatives

The following parts are listed as comparable options for similar EPROM-based program storage applications.

Alternative Part	Technical Difference	Application Difference	Selection Advice
M27C4001-12F1	5V-only operation (V_CC = 4.5–5.5V); 120 ns access; UV-erasable; FDIP32W package with quartz window.	Requires 5V supply and UV eraser; suitable for prototyping and reprogrammable lab environments-not for battery-powered or low-voltage systems.	Select when reusability and development flexibility outweigh low-voltage operation and industrial temperature needs.
AT27C040-70PU	4 Mbit OTP EPROM; 70 ns access at 5V; PDIP32; Atmel (now Microchip) silicon; same pinout but different electronic signature (1Fh/30h).	Compatible footprint but requires programmer firmware update for signature recognition; no Presto II support-uses standard 100 µs pulse algorithm.	Select when sourcing diversity is required and existing tooling can accommodate signature reconfiguration.

Compared with M27W401-80B6, M27C4001-12F1 demands higher voltage and UV infrastructure but offers field reusability, while AT27C040-70PU provides faster access at 5V but lacks Presto II margin assurance and requires toolchain adaptation-M27W401-80B6 uniquely balances low-voltage operation, industrial temp, and drop-in M27C4001 compatibility.

Availability

M27W401-80B6 is available at Aetrix Electronics and suitable for industrial PLC firmware storage, legacy automotive ECU boot memory, and medical device configuration ROM requiring stable component supply across extended product lifecycles.

Supply support for M27W401-80B6 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, specializing in automotive, industrial, and power management ICs with broad legacy product support.

The M27W401 belongs to ST's mature EPROM product line, designed specifically for cost-sensitive, long-lifecycle embedded systems requiring pin-compatible upgrades from 5V EPROMs without board redesign.

FAQ

Is M27W401-80B6 UV-erasable or one-time programmable?

M27W401-80B6 is an OTP (one-time programmable) variant packaged in PDIP32 (B suffix), meaning it lacks a quartz window and cannot be UV-erased. It shares the same die and programming algorithm as the UV-erasable FDIP32W version but is permanently programmed during manufacturing or final test. Erasure is physically impossible after packaging.

What is the correct V_CC voltage during programming?

During programming, V_CC must be set to 6.25V ± 0.25V while V_PP is held at 12.75V ± 0.25V. This dual-voltage requirement is mandatory-using 3.3V or 5V on V_CC during programming will fail to inject sufficient charge into the floating gate and result in incomplete or non-retentive writes.

Can M27W401-80B6 be used as a direct replacement for M27C4001 in existing designs?

Yes-M27W401-80B6 is pin-, signal-, and electronic signature-compatible (20h/41h) with M27C4001. However, it operates at 2.7–3.6V (vs. 4.5–5.5V), so level-shifting or supply adjustment is required if the host system lacks a 3.3V rail. The Presto II algorithm is identical, enabling use of the same programmer firmware.

Does M27W401-80B6 support common memory bus protocols like ISA or VME?

No-it is a parallel asynchronous EPROM with simple E/G control and no protocol logic. It interfaces directly to generic microprocessor address/data buses (e.g., 8051, 68000, Z80) using standard read strobe timing. Protocol compliance (ISA/VME) depends entirely on the surrounding glue logic and bus controller-not the EPROM itself.

M27W401-80B6 Specifications

Product attributes: Attribute value

Manufacturer:: STMicroelectronics

Series:: -

Package/Case:: 32-DIP (0.600", 15.24mm)

Packaging:: Tube

Product Status:: Obsolete

Programmable:: Not Verified

Memory Type:: Non-Volatile

Memory Format:: EPROM

Technology:: EPROM - OTP

Memory Size:: 4Mbit

Memory Organization:: 512K x 8

Memory Interface:: Parallel

Clock Frequency:: -

Write Cycle Time - Word, Page:: -

Access Time:: 80 ns

Voltage - Supply:: 2.7V ~ 3.6V

Operating Temperature:: -40°C ~ 85°C (TA)

Grade:: -

Qualification:: -

Mounting Type:: Through Hole

Supplier Device Package:: 32-PDIP

M27W401-80B6 FAQ

1.How can I place an order for M27W401-80B6 through Aetrix?

Please submit a Request for Quotation (RFQ) for M27W401-80B6 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 M27W401-80B6 reliable?

The price and inventory of M27W401-80B6 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for M27W401-80B6 is usually 5 days.

3.What payment methods are accepted for M27W401-80B6?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for M27W401-80B6 transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for M27W401-80B6?

M27W401-80B6 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your M27W401-80B6 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 M27W401-80B6?

For technical support, including M27W401-80B6 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your M27W401-80B6 requirements.

6.How does Aetrix verify that M27W401-80B6 is sourced from the original manufacturer or authorized distributors?

All M27W401-80B6 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 M27W401-80B6 meets industry standards.

7.What is the process for return or replacement of M27W401-80B6?

All M27W401-80B6 units undergo pre-shipment inspection (PSI). If there is an issue with M27W401-80B6, 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 M27W401-80B6 part is unused and in its original packaging.

Return procedure for M27W401-80B6:

1.Submit a request within 90 days.

2.Obtain a Return Material Authorization (RMA) from Aetrix.

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