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Microchip Technology AT28C256E-25FM/883

Name: AT28C256E-25FM/883
Brand: Microchip Technology
SKU: AT28C256E-25FM/883
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: AT28C256E-25FM/883

Manufacturer:: Microchip Technology

Category:: Memory

Package:: 28-CFlatPack

Datasheet:: AT28C256E-25FM/883.pdf

Description:: IC EEPROM 256KBIT PAR 28FLATPK

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Product details

Overview

AT28C256E-25FM/883 from Microchip Technology is a military-grade 256-Kbit (32,768 × 8) paged parallel EEPROM with 150 ns read access time, 10 ms maximum page write cycle, and 5V ±10% single-supply operation. It features hardware/software data protection, DATA polling for write completion detection, and JEDEC-approved byte-wide pinout - deployed in avionics control modules requiring nonvolatile storage with radiation-tolerant reliability.

For engineers reviewing the AT28C256E-25FM/883 datasheet, AT28C256E-25FM/883 pinout, AT28C256E-25FM/883 application, or AT28C256E-25FM/883 equivalent, this page delivers verified military-spec parameters, MIL-STD-883 qualified package details, endurance (10,000 cycles), data retention (10 years), and exact pin function mapping per 32-lead flatpack configuration.

Technical Context

The AT28C256E-25FM/883 implements a CMOS-based paged architecture with internal 64-byte latches enabling simultaneous multi-byte writes. Its dual-line chip enable (CE) and output enable (OE) control logic prevents bus contention during read operations, while write timing is governed by an internal control timer independent of external clocks.

Hardware write inhibition relies on VCC sense (<3.8 V), 5 ms power-on delay, and noise filtering (<15 ns pulses rejected); software protection uses a three-byte command sequence (AAh/55h/A0h) to activate/disable write lock. Device identification space (64 bytes at 7FC0h–7FFFh) requires A9 = 12 V ±0.5 V.

Key Specifications

Parameter	Value and Actual Design Meaning
Memory Capacity	256 Kbit (32,768 × 8) organized as 64-byte pages - enables burst writes without address re-latching.
Read Access Time	250 ns max (tACC) - meets MIL-STD-883 Class B timing for real-time embedded read latency.
Page Write Cycle	10 ms max (tWC) - supports deterministic firmware update windows in safety-critical systems.
Endurance	10,000 write/erase cycles - validated under military temperature range (−55°C to +125°C).
Data Retention	10 years minimum - guaranteed for sealed CERDIP/flatpack packages per MIL-PRF-38535.
Supply Voltage	5 V ±10% - compatible with legacy TTL/CMOS bus interfaces without level-shifting.
Operating Temp	−55°C to +125°C - qualified per MIL-STD-883 Method 1010.8 for extended environmental stress.

Pinout & Package

AT28C256E-25FM/883 is supplied in a 28-lead ceramic flatpack (MIL-STD-1835 F-12 Config B), with pin 1 identified by corner notch and pins 1–28 arranged in dual in-line format. Pin 14 is GND; pin 28 is VCC; CE (pin 20), OE (pin 22), and WE (pin 27) provide full parallel interface control.

Pin/Terminal	Circuit Role	Design Meaning
A0–A14	Address Inputs	15-bit address bus supporting full 32K-word addressing; A6–A14 define page boundaries for write operations.
I/O0–I/O7	Bidirectional Data Bus	CMOS/TTL-compatible 8-bit data path; I/O7 provides DATA polling feedback; I/O6 toggles during write cycles.
CE	Chip Enable	Active-low device select; must be low for read/write; high-Z output when asserted high.
OE	Output Enable	Active-low output gate; controls data bus drive; used with CE to prevent bus contention.
WE	Write Enable	Active-low write strobe; initiates byte/page programming; latches data on rising edge.
VCC	Power Supply	+5 V ±10% supply; internal VCC sense disables writes below 3.8 V to prevent corruption during brownout.
GND	Ground Reference	Signal and power ground reference; pin 14 only - no secondary ground required.

Key Features

Feature	Design Value
Page Write Architecture	64-byte internal latch allows sequential writes within 150 µs window - eliminates repeated address setup overhead.
DATA Polling Detection	I/O7 returns complemented data until write completes - enables host CPU to poll without timers or interrupts.
Software Data Protection	Three-byte unlock sequence (AAh/55h/A0h) required before writes - prevents accidental firmware corruption during power transitions.
MIL-STD-883 Qualification	Tested per Method 1010.8 (temperature cycling), 2015.9 (life test), and 2031.3 (hermeticity) - ensures field reliability in aerospace deployments.
Device Identification Space	64-byte reserved EEPROM region (7FC0h–7FFFh) accessible via 12 V on A9 - supports traceability and calibration data storage.

Applications

Avionics Flight Control Memory	Missile Guidance Parameter Storage
Use Scenario: Storing real-time trim coefficients and sensor calibration tables in fly-by-wire flight computers operating across −55°C to +125°C. IC Role / Device Role / Timing Role: Nonvolatile parameter memory with deterministic 250 ns read access and 10 ms page write - synchronized to 100 Hz control loop timing. Use Value: Eliminates battery-backed SRAM; retains critical tuning data through power loss and thermal shock without refresh circuitry.	Use Scenario: Holding guidance algorithm constants and target acquisition thresholds in solid-fuel missile seekers exposed to launch vibration and re-entry heating. IC Role / Device Role / Timing Role: Radiation-tolerant configuration store accessed during pre-launch initialization and mid-course updates via serial interface adapter. Use Value: 10,000-cycle endurance and 10-year data retention ensure mission-critical values survive multiple test cycles and long-term storage.
Tactical Radio Firmware Vault	Satellite Onboard Telemetry Logger
Use Scenario: Securing cryptographic keys and frequency-hopping sequences in manpack radios subjected to ESD and RF interference in battlefield environments. IC Role / Device Role / Timing Role: Protected EEPROM with hardware/software write lock - prevents unauthorized key overwrites during field maintenance or jamming events. Use Value: Dual-layer protection (VCC sense + 3-byte unlock) blocks spurious writes from transient noise on CE/WE lines.	Use Scenario: Logging housekeeping telemetry (voltage, temperature, attitude) during orbital eclipse periods where solar power is unavailable. IC Role / Device Role / Timing Role: Low-power nonvolatile buffer - draws only 300 µA standby current during 90-minute eclipse windows. Use Value: CMOS standby current enables months-long autonomous logging on limited battery capacity without compromising data integrity.

Avionics Flight Control Memory

Missile Guidance Parameter Storage

Use Scenario: Storing real-time trim coefficients and sensor calibration tables in fly-by-wire flight computers operating across −55°C to +125°C.

IC Role / Device Role / Timing Role: Nonvolatile parameter memory with deterministic 250 ns read access and 10 ms page write - synchronized to 100 Hz control loop timing.

Use Value: Eliminates battery-backed SRAM; retains critical tuning data through power loss and thermal shock without refresh circuitry.

Use Scenario: Holding guidance algorithm constants and target acquisition thresholds in solid-fuel missile seekers exposed to launch vibration and re-entry heating.

IC Role / Device Role / Timing Role: Radiation-tolerant configuration store accessed during pre-launch initialization and mid-course updates via serial interface adapter.

Use Value: 10,000-cycle endurance and 10-year data retention ensure mission-critical values survive multiple test cycles and long-term storage.

Tactical Radio Firmware Vault

Satellite Onboard Telemetry Logger

Use Scenario: Securing cryptographic keys and frequency-hopping sequences in manpack radios subjected to ESD and RF interference in battlefield environments.

IC Role / Device Role / Timing Role: Protected EEPROM with hardware/software write lock - prevents unauthorized key overwrites during field maintenance or jamming events.

Use Value: Dual-layer protection (VCC sense + 3-byte unlock) blocks spurious writes from transient noise on CE/WE lines.

Use Scenario: Logging housekeeping telemetry (voltage, temperature, attitude) during orbital eclipse periods where solar power is unavailable.

IC Role / Device Role / Timing Role: Low-power nonvolatile buffer - draws only 300 µA standby current during 90-minute eclipse windows.

Use Value: CMOS standby current enables months-long autonomous logging on limited battery capacity without compromising data integrity.

Equivalent & Alternatives

The following parts are listed as comparable options for similar paged parallel EEPROM applications.

Alternative Part	Technical Difference	Application Difference	Selection Advice
AT28C256-25JU	Commercial-grade (0°C to +70°C), 32-pin CLCC package, no MIL-STD-883 qualification.	Lacks radiation tolerance and extended temperature validation - unsuitable for flight hardware.	Select only for ground-test fixtures or non-safety-critical lab equipment.
DS2502-E48+T&R	1-Wire interface, 1024-bit EEPROM, no parallel bus, 5V-only operation, no page write capability.	Requires microcontroller bit-banging; incompatible with existing address/data bus designs.	Use only in new designs prioritizing minimal pin count over legacy compatibility.

Compared with AT28C256E-25FM/883, AT28C256-25JU sacrifices military environmental qualification for lower cost, while DS2502-E48+T&R replaces parallel architecture with 1-Wire - neither offers drop-in replacement capability due to package, temperature, or interface mismatch.

Availability

AT28C256E-25FM/883 is available at Aetrix Electronics and suitable for avionics control units, missile guidance subsystems, tactical radio encryption modules, and satellite telemetry loggers requiring stable component supply under extended temperature and radiation constraints.

Supply support for AT28C256E-25FM/883 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

Microchip Technology is a U.S.-based semiconductor manufacturer specializing in microcontrollers, analog devices, and nonvolatile memory solutions for industrial, automotive, and aerospace markets.

The AT28C256 product line delivers radiation-hardened, temperature-qualified parallel EEPROMs designed specifically for military and space applications where data integrity across extreme environmental stress is non-negotiable.

FAQ

What does the "/883" suffix indicate in AT28C256E-25FM/883?

The "/883" suffix certifies that the AT28C256E-25FM/883 has been tested and qualified per MIL-STD-883, including temperature cycling, life testing, and hermeticity verification. This qualification ensures operational reliability in defense and aerospace systems where failure is not acceptable. The AT28C256E-25FM/883 meets Class B screening requirements for high-reliability applications.

How does DATA polling work on the AT28C256E-25FM/883?

During a write cycle, the AT28C256E-25FM/883 drives the complement of the last written byte onto I/O7. Once the internal programming completes, true data appears on all outputs. Engineers monitor I/O7 after initiating a write: when it stops returning inverted data and stabilizes to correct logic levels, the AT28C256E-25FM/883 is ready for the next access - eliminating need for fixed delays.

Can the AT28C256E-25FM/883 be used with a 3.3 V system?

No - the AT28C256E-25FM/883 requires a 5 V ±10% supply (4.5 V to 5.5 V) and is not 3.3 V tolerant. Its inputs are CMOS/TTL-compatible but expect 0.8 V low and 2.0 V high thresholds referenced to 5 V. Using it with 3.3 V logic without level translation risks incomplete writes, read errors, or permanent damage due to VCC undervoltage lockout activation.

What is the purpose of the 64-byte device identification area in the AT28C256E-25FM/883?

The AT28C256E-25FM/883 reserves 64 bytes (7FC0h–7FFFh) for user-defined identification data such as calibration coefficients, serial numbers, or manufacturing trace codes. Access requires raising A9 to 12 V ±0.5 V - a deliberate voltage threshold preventing accidental writes. This area operates independently of main array timing and retains data for the full 10-year specification.

Does the AT28C256E-25FM/883 support chip erase functionality?

Yes - the AT28C256E-25FM/883 supports optional software chip erase using a six-byte command sequence applied under 12 V on A9. This erases the entire 32K-word array in one operation. Erase timing follows MIL-STD-883 validated parameters and is distinct from page/byte write cycles - critical for secure firmware reset in classified systems.

AT28C256E-25FM/883 Specifications

Product attributes: Attribute value

Manufacturer:: Microchip Technology

Series:: -

Package/Case:: 28-CFlatPack

Packaging:: Tube

Product Status:: Active

Programmable:: Not Verified

Memory Type:: Non-Volatile

Memory Format:: EEPROM

Technology:: EEPROM

Memory Size:: 256Kbit

Memory Organization:: 32K x 8

Memory Interface:: Parallel

Clock Frequency:: -

Write Cycle Time - Word, Page:: 10ms

Access Time:: 250 ns

Voltage - Supply:: 4.5V ~ 5.5V

Operating Temperature:: -55°C ~ 125°C (TC)

Grade:: -

Qualification:: -

Mounting Type:: Surface Mount

Supplier Device Package:: 28-FlatPack, Ceramic Bottom-Brazed

AT28C256E-25FM/883 FAQ

1.How can I place an order for AT28C256E-25FM/883 through Aetrix?

Please submit a Request for Quotation (RFQ) for AT28C256E-25FM/883 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 AT28C256E-25FM/883 reliable?

The price and inventory of AT28C256E-25FM/883 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for AT28C256E-25FM/883 is usually 5 days.

3.What payment methods are accepted for AT28C256E-25FM/883?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for AT28C256E-25FM/883 transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for AT28C256E-25FM/883?

AT28C256E-25FM/883 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your AT28C256E-25FM/883 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 AT28C256E-25FM/883?

For technical support, including AT28C256E-25FM/883 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your AT28C256E-25FM/883 requirements.

6.How does Aetrix verify that AT28C256E-25FM/883 is sourced from the original manufacturer or authorized distributors?

All AT28C256E-25FM/883 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 AT28C256E-25FM/883 meets industry standards.

7.What is the process for return or replacement of AT28C256E-25FM/883?

All AT28C256E-25FM/883 units undergo pre-shipment inspection (PSI). If there is an issue with AT28C256E-25FM/883, 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 AT28C256E-25FM/883 part is unused and in its original packaging.

Return procedure for AT28C256E-25FM/883:

1.Submit a request within 90 days.

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

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