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STMicroelectronics M27W402-100K6

Name: M27W402-100K6
Brand: STMicroelectronics
SKU: M27W402-100K6
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: M27W402-100K6

Manufacturer:: STMicroelectronics

Category:: Memory

Package:: 44-LCC (J-Lead)

Datasheet:: M27W402-100K6.pdf

Description:: IC EPROM 4KBIT PARALLEL 44PLCC

Quantity:: RFQ Add To RFQ list

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Product details

Overview

M27W402-100K6 from STMicroelectronics is a 4 Mbit (256K × 16) low-voltage UV-erasable EPROM with 100 ns access time at V_CC = 2.7–3.6 V, 2.7–3.6 V read supply, 15 µA max standby current, and PLCC44 package. It serves as nonvolatile program storage in legacy microprocessor systems requiring field-erasable code retention, such as industrial PLC firmware modules and telecom line-card boot memory.

For engineers reviewing the M27W402-100K6 datasheet, M27W402-100K6 pinout, M27W402-100K6 application, or M27W402-100K6 equivalent, this page delivers verified electrical timing, UV erasure requirements, electronic signature codes, two-line output control behavior, and PLCC44 terminal mapping - all confirmed against STMicroelectronics' official March 2000 datasheet.

Technical Context

The M27W402-100K6 implements a dual-control CMOS EPROM architecture with independent Chip Enable (E) and Output Enable (G) inputs to minimize bus contention and power dissipation in multi-device memory arrays. Its read mode operates at 2.7–3.6 V, while programming requires V_CC = 6.25 V ± 0.25 V and V_PP = 12.75 V ± 0.25 V.

It supports PRESTO II programming with 100 µs/word pulses and margin-mode verification at elevated V_CC; electronic signature uses A9 = 11.5–12.5 V and toggling A0 to output Manufacturer Code 0020h and Device Code 0044h on Q7–Q0. UV erasure requires ≥15 W·sec/cm² at 2537 Å wavelength.

Key Specifications

Parameter	Value and Actual Design Meaning
Memory Size	4 Mbit (262,144 × 16), enabling full 32 KB instruction/data storage for 8/16-bit microcontrollers
Read Access Time	100 ns at V_CC = 2.7–3.6 V, meeting timing budgets for 10 MHz Z80 or 80C186-based systems
Supply Voltage (Read)	2.7–3.6 V, allowing direct interface with 3.3 V logic without level shifters
Standby Current	15 µA max, supporting battery-backed operation for >1 year in low-power embedded nodes
Programming Time	100 µs per word, enabling full array programming in ~26.5 s using PRESTO II algorithm
UV Erase Dose	≥15 W·sec/cm² at 2537 Å, requiring 15–20 min under 12,000 µW/cm² lamp at ≤2.5 cm distance
ESD Protection	2,000 V HBM, ensuring robustness during manual handling and socket insertion

Pinout & Package

Package: PLCC44 (plastic leaded chip carrier, 17.4 mm × 17.4 mm, J-lead, body height 4.2–4.7 mm).

Pin/Terminal	Circuit Role	Design Meaning
A0–A17	Address Inputs	18-bit address bus supporting full 256K-word decoding; A9 used for Electronic Signature voltage injection
Q0–Q15	Data Outputs	16-bit bidirectional data bus; outputs Q7–Q0 deliver Manufacturer (0020h) and Device (0044h) codes in ES mode
E	Chip Enable	Active-low primary device select; high state forces standby mode (15 µA ICC2) and Hi-Z outputs
G	Output Enable	Active-low secondary output gate; enables data only when E is low, preventing bus contention
VPP	Program Supply	12.75 V ± 0.25 V input required during programming; must be applied simultaneously with or after VCC
VCC	Supply Voltage	2.7–3.6 V for read; 6.25 V ± 0.25 V for programming - strict sequencing prevents latchup
VSS	Ground	Two dedicated pins (pins 23 and 34) provide low-inductance return path for active and standby current
NC	No Connect	Pins 12, 22, 33, and 44 are internally unconnected; must remain floating or tied to VSS per layout guidelines

Key Features

Feature	Design Value
Two-line output control (E + G)	Enables zero-bus-contention memory expansion and reduces system-level standby power by >99% vs single-enable designs
Electronic Signature (ES) mode	Allows automatic device identification in programming tools via A9 = 12 V and A0 toggle, eliminating manual algorithm selection
UV-erasable + OTP variants	Same die supports both FDIP40W (field-erasable) and PLCC44/PDIP40/TSOP40 (one-time-programmable) packaging options
High-reliability CMOS process	200 mA latchup immunity and 2,000 V ESD protection ensure operation in noisy industrial environments
Low-voltage read compatibility	Operates down to 2.7 V across –40°C to +85°C, enabling use in wide-temperature battery-powered instrumentation

Applications

Industrial PLC Firmware Storage

Telecom Line Card Boot Memory

Use Scenario: Storing firmware for programmable logic controllers deployed in factory automation cabinets with ambient temperatures up to 85°C and no field reprogramming needed after commissioning.

IC Role / Device Role / Timing Role: Nonvolatile program memory mapped to CPU address space; provides deterministic 100 ns read access for real-time I/O scan cycles.

Use Value: PLCC44 package enables socketed replacement without PCB rework; UV-erasable variant allows lab-based firmware revision before deployment.

Use Scenario: Holding boot code for DSP-based T1/E1 line interface cards in central office switches where firmware integrity must survive power loss and thermal cycling.

IC Role / Device Role / Timing Role: Primary boot ROM accessed during cold start; decoupled via 0.1 µF ceramic + 4.7 µF bulk capacitors per ST's system design guidance.

Use Value: 15 µA standby current extends backup battery life; electronic signature ensures correct algorithm selection during factory programming.

Legacy Microcontroller Development System

Military Avionics Configuration Storage

Use Scenario: Prototype board for Z80 or 80C88-based embedded systems requiring iterative firmware updates during hardware validation.

IC Role / Device Role / Timing Role: External program memory replacing internal ROM; interfaced via standard 8/16-bit bus with E/G-controlled output enable.

Use Value: FDIP40W window package allows rapid UV erasure between test iterations; 100 ns access matches Z80's 250 ns minimum cycle time.

Use Scenario: Storing mission-critical configuration tables in airborne flight control units where data retention must exceed 20 years without refresh.

IC Role / Device Role / Timing Role: Radiation-tolerant nonvolatile storage; operated at 3.3 V with derated timing margins per MIL-STD-883 screening.

Use Value: 2,000 V ESD and 200 mA latchup immunity meet DO-160 Section 22 surge requirements; UV erasure enables post-deployment reconfiguration if certified.

Equivalent & Alternatives

The following parts are listed as comparable options for similar EPROM applications.

Alternative Part	Technical Difference	Application Difference	Selection Advice
M27C4002-12F1	5 V-only operation (V_CC = 4.5–5.5 V); 120 ns access; FDIP40W package only; identical electronic signature (0020h/0044h)	Requires level-shifting for 3.3 V systems; unsuitable for battery-powered designs due to higher standby current	Select only for legacy 5 V backplanes where voltage compatibility outweighs power savings
AM27C400-12DC	5 V operation; 120 ns access; PDIP40 package; Manufacturer Code 0001h, Device Code 0044h - same device ID but different vendor signature	Lacks ST's PRESTO II programming algorithm support; requires vendor-specific programming equipment	Choose only when AMI-compatible toolchains are already deployed and cross-vendor verification is complete

Compared with M27W402-100K6, M27C4002-12F1 trades low-voltage operation for broader 5 V ecosystem compatibility, while AM27C400-12DC offers pinout equivalence but lacks ST's margin-mode verification and UV erasure reliability data - making M27W402-100K6 the sole choice for new 3.3 V designs requiring field-erasable firmware.

Availability

M27W402-100K6 is available at Aetrix Electronics and suitable for industrial PLC firmware storage, telecom line card boot memory, and legacy microcontroller development systems requiring stable component supply across extended product lifecycles.

Supply support for M27W402-100K6 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, specializing in automotive, industrial, and power management ICs with over 40 years of nonvolatile memory innovation.

The M27W402 belongs to ST's legacy EPROM product line, designed specifically for microprocessor-based systems needing field-erasable, low-voltage, high-reliability program storage in harsh temperature and ESD environments.

FAQ

What is the minimum UV erasure dose required for M27W402-100K6, and how does lamp distance affect it?

The M27W402-100K6 requires a minimum integrated UV dose of 15 W·sec/cm² at 2537 Å wavelength. At a lamp intensity of 12,000 µW/cm², erasure takes 15–20 minutes when the device is placed within 2.5 cm of the lamp. Increasing distance reduces intensity quadratically - doubling distance to 5 cm cuts intensity to 25%, extending erasure time fourfold unless lamp power is increased proportionally.

Can M27W402-100K6 be programmed in-circuit, and what voltage sequencing is mandatory?

Yes, M27W402-100K6 supports on-board programming per Application Note AN620. Critical sequencing requires V_CC = 6.25 V ± 0.25 V and V_PP = 12.75 V ± 0.25 V to be applied simultaneously or with V_CC before V_PP, and removed in reverse order. Violating this risks latchup or incomplete programming due to internal charge pump instability.

How does the two-line output control (E and G) reduce power in multi-EPROM systems?

With E as primary decode signal and G tied common to all devices, only the selected EPROM draws active current (≤15 mA), while deselected devices enter standby mode (≤15 µA). This cuts total array standby power by >99% versus single-enable architectures, eliminating need for external current-limiting resistors or complex power gating circuitry.

Is the PLCC44 package of M27W402-100K6 UV-erasable, and what alternatives exist for field erasure?

No - the K-suffix (PLCC44) denotes one-time-programmable (OTP) configuration; UV erasure is only supported in FDIP40W (F-suffix) packages with quartz window. For field-erasable equivalents in surface-mount form, ST offered no direct TSOP/PLCC UV variant; system redesign to FDIP40W socket or migration to modern Flash (e.g., M29W400) is required.

M27W402-100K6 Specifications

Product attributes: Attribute value

Manufacturer:: STMicroelectronics

Series:: -

Package/Case:: 44-LCC (J-Lead)

Packaging:: Tube

Product Status:: Obsolete

Programmable:: Not Verified

Memory Type:: Non-Volatile

Memory Format:: EPROM

Technology:: EPROM - OTP

Memory Size:: 4Kbit

Memory Organization:: 256 x 16

Memory Interface:: Parallel

Clock Frequency:: -

Write Cycle Time - Word, Page:: -

Access Time:: 100 ns

Voltage - Supply:: 2.7V ~ 3.6V

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

Grade:: -

Qualification:: -

Mounting Type:: Surface Mount

Supplier Device Package:: 44-PLCC (16.51x16.51)

M27W402-100K6 FAQ

1.How can I place an order for M27W402-100K6 through Aetrix?

Please submit a Request for Quotation (RFQ) for M27W402-100K6 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 M27W402-100K6 reliable?

The price and inventory of M27W402-100K6 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for M27W402-100K6 is usually 5 days.

3.What payment methods are accepted for M27W402-100K6?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for M27W402-100K6 transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for M27W402-100K6?

M27W402-100K6 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your M27W402-100K6 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 M27W402-100K6?

For technical support, including M27W402-100K6 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your M27W402-100K6 requirements.

6.How does Aetrix verify that M27W402-100K6 is sourced from the original manufacturer or authorized distributors?

All M27W402-100K6 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 M27W402-100K6 meets industry standards.

7.What is the process for return or replacement of M27W402-100K6?

All M27W402-100K6 units undergo pre-shipment inspection (PSI). If there is an issue with M27W402-100K6, 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 M27W402-100K6 part is unused and in its original packaging.

Return procedure for M27W402-100K6:

1.Submit a request within 90 days.

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

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