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Home > Products > Integrated Circuits (ICs) > Memory > Memory

Microchip Technology AT28HC256E-12UM/883

Name: AT28HC256E-12UM/883
Brand: Microchip Technology
SKU: AT28HC256E-12UM/883
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: AT28HC256E-12UM/883

Manufacturer:: Microchip Technology

Category:: Memory

Package:: 28-BCPGA

Datasheet:: AT28HC256E-12UM/883.pdf

Description:: IC EEPROM 256KBIT PAR 28CPGA

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Product details

Overview

AT28HC256E-12UM/883 from Microchip Technology is a military-grade 256-Kbit (32,768 × 8) paged parallel EEPROM with 120 ns read access time, 10 ms maximum page write cycle time, and full operation across –55°C to +125°C. It features hardware/software data protection, DATA polling and toggle-bit write completion detection, and JEDEC-standard byte-wide pinout for integration into avionics, missile guidance, and hardened embedded control systems.

For engineers reviewing the AT28HC256E-12UM/883 datasheet, AT28HC256E-12UM/883 pinout, AT28HC256E-12UM/883 application, or AT28HC256E-12UM/883 equivalent, this page delivers verified military-spec timing, endurance (100,000 cycles), packaging (30-pin PGA), and interface compatibility (5V ±10%, TTL/CMOS I/O) required for high-reliability system design and qualification.

Technical Context

The AT28HC256E-12UM/883 implements a paged architecture with a 64-byte internal latch, enabling 1–64-byte writes within a single internal programming period. Its dual-line chip enable (CE) and output enable (OE) control supports bus contention avoidance in multiprocessor environments.

It integrates VCC sense circuitry (write inhibit below 3.8 V), 5 ms power-on delay, noise filtering (<15 ns pulse rejection), and software data protection via three-step command sequences (AAh/55h/A0h for enable; AAh/55h/80h/AAh/20h for disable), all operating within the same 5V supply without auxiliary voltages except for optional 12V chip erase.

Key Specifications

Parameter	Value and Actual Design Meaning
Memory Density	256 Kbit (32,768 × 8) - provides nonvolatile storage for firmware boot code, calibration tables, or mission-critical configuration data in space-constrained military platforms.
Read Access Time	120 ns - enables direct replacement of SRAM in legacy MIL-STD-1553 or discrete logic-based controllers without timing redesign.
Page Write Cycle Time	10 ms max - supports rapid field updates of parameter sets or sensor compensation coefficients without system downtime.
Endurance	100,000 write/erase cycles - meets extended service life requirements for onboard diagnostics and reprogrammable flight software modules.
Data Retention	10 years at +125°C - ensures persistent storage integrity over full operational lifetime in jet engine-mounted electronics or satellite power management units.
Supply Voltage	5 V ±10% - compatible with standard military 5V power buses and eliminates need for dedicated voltage regulators in legacy designs.
Operating Temperature	–55°C to +125°C - qualified per MIL-PRF-38535 Class B and screened to SMD 5962-88634, supporting deployment in radar front-ends and hypersonic vehicle avionics.

Pinout & Package

AT28HC256E-12UM/883 is packaged in a 30-pin Ceramic Pin Grid Array (PGA), compliant with MIL-STD-1835 28U configuration. Pin 1 is index-marked; pins are arranged in two staggered rows with 2.54 mm pitch.

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 64-byte page writes.
I/O0–I/O7	Bidirectional Data Bus	Byte-wide parallel interface compatible with 80C86, Z80, and MIL-STD-1750A microprocessors; supports DATA polling on I/O7 and toggle-bit detection on I/O6.
CE	Chip Enable	Active-low device select; must be low with OE low and WE high for read access; initiates write when pulsed low with OE high.
OE	Output Enable	Active-low output control; places I/O lines in high-impedance state when high, preventing bus contention during shared-memory operations.
WE	Write Enable	Active-low write strobe; latches address and data on falling edge; controls byte/page write initiation and software protection command sequencing.
VCC	Power Supply	+5 V ±10% main supply; powers core logic and I/O buffers; internal VCC sense disables writes below 3.8 V.
GND	Ground Reference	Signal and power return path; decoupling capacitor placement near pin 14 critical for noise immunity in RF-dense environments.
A9 (12V)	High-Voltage Programming	Accepts 12.0 V ±0.5 V for device identification memory access (7FC0h–7FFFh) and optional chip erase mode.

Key Features

Feature	Design Value
Hardware Data Protection	VCC sense, 5 ms power-on delay, and noise-filtered CE/WE inputs prevent spurious writes during power transients in airborne power systems.
Software Data Protection	Three-step command sequence (AAh/55h/A0h) enables selective write-locking of entire array-critical for safeguarding flight control constants in safety-critical applications.
Page Write Architecture	64-byte internal latch allows burst loading of calibration data or telemetry logs without repeated address setup, reducing CPU overhead by >85% vs. byte-write mode.
Write Completion Detection	Dual methods-DATA polling (I/O7 complement inversion) and toggle-bit (I/O6 state alternation)-enable deterministic timing for real-time interrupt-driven write acknowledgment.
Military Screening	Qualified to MIL-PRF-38535 Class B, tested per Method 5005, and marked per SMD 5962-88634-ensuring traceability, lot control, and radiation tolerance for defense programs.

Applications

Avionics Boot Memory	Mission-Critical Parameter Storage
Use Scenario: Stores bootloader firmware and FPGA configuration bitstreams in radar signal processors requiring cold-start reliability after thermal cycling. IC Role / Device Role / Timing Role: Nonvolatile program memory mapped to CPU address space; accessed as static RAM during power-up initialization. Use Value: 120 ns read access ensures boot latency < 50 µs; 100,000-cycle endurance supports 10+ years of field reprogramming without degradation.	Use Scenario: Holds real-time calibration coefficients for inertial measurement units (IMUs) in guided munitions subjected to high-g shock and wide temperature swings. IC Role / Device Role / Timing Role: Parameter EEPROM interfaced via discrete address/data bus; updated only during pre-launch ground checkout. Use Value: 10-year data retention at +125°C guarantees coefficient validity throughout shelf life and operational envelope.
Hardened Telemetry Logger	Secure Configuration Vault
Use Scenario: Captures fault logs and sensor snapshots in satellite power management units exposed to total ionizing dose (TID) up to 100 krad(Si). IC Role / Device Role / Timing Role: Write-once logging memory with page-write capability; triggered by watchdog timeout or voltage brownout events. Use Value: Page write reduces write time by 97% vs. byte mode, minimizing exposure during radiation-sensitive write windows.	Use Scenario: Secures cryptographic keys and platform identity tokens in secure communication modules used in tactical radios. IC Role / Device Role / Timing Role: Protected configuration store with software data protection enabled; write access gated by authentication handshake. Use Value: Three-step SDP lock prevents unauthorized key overwrite during maintenance or field servicing-even under voltage glitch attacks.

Avionics Boot Memory

Mission-Critical Parameter Storage

Use Scenario: Stores bootloader firmware and FPGA configuration bitstreams in radar signal processors requiring cold-start reliability after thermal cycling.

IC Role / Device Role / Timing Role: Nonvolatile program memory mapped to CPU address space; accessed as static RAM during power-up initialization.

Use Value: 120 ns read access ensures boot latency < 50 µs; 100,000-cycle endurance supports 10+ years of field reprogramming without degradation.

Use Scenario: Holds real-time calibration coefficients for inertial measurement units (IMUs) in guided munitions subjected to high-g shock and wide temperature swings.

IC Role / Device Role / Timing Role: Parameter EEPROM interfaced via discrete address/data bus; updated only during pre-launch ground checkout.

Use Value: 10-year data retention at +125°C guarantees coefficient validity throughout shelf life and operational envelope.

Hardened Telemetry Logger

Secure Configuration Vault

Use Scenario: Captures fault logs and sensor snapshots in satellite power management units exposed to total ionizing dose (TID) up to 100 krad(Si).

IC Role / Device Role / Timing Role: Write-once logging memory with page-write capability; triggered by watchdog timeout or voltage brownout events.

Use Value: Page write reduces write time by 97% vs. byte mode, minimizing exposure during radiation-sensitive write windows.

Use Scenario: Secures cryptographic keys and platform identity tokens in secure communication modules used in tactical radios.

IC Role / Device Role / Timing Role: Protected configuration store with software data protection enabled; write access gated by authentication handshake.

Use Value: Three-step SDP lock prevents unauthorized key overwrite during maintenance or field servicing-even under voltage glitch attacks.

Equivalent & Alternatives

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

Alternative Part	Technical Difference	Application Difference	Selection Advice
AT28HC256F-12UM/883	3 ms maximum page write time (vs. 10 ms); same pinout, voltage, and temperature range.	Preferred where rapid field updates are required-e.g., electronic warfare jamming waveform reloads between missions.	Select F-version when write speed outweighs cost sensitivity; verify system timing margins accommodate faster tWC.
DS2502-E48+T&R	1-Wire serial interface (vs. parallel); 1024-bit EPROM (vs. 256 Kbit); no software protection or page write.	Suitable for simple ID tagging or minimal configuration storage where board space and pin count are constrained.	Choose DS2502 only for low-complexity, low-density identity storage-not as functional replacement for AT28HC256E-12UM/883's parallel interface or protected write capability.

Compared with AT28HC256F-12UM/883, the AT28HC256E-12UM/883 trades write speed for higher endurance rating (100K vs. 10K cycles), making it preferable for long-life systems with infrequent but mission-critical updates; versus DS2502-E48+T&R, it offers 256× more density, parallel throughput, and military-grade write protection-essential for avionics and weapon system control.

Availability

AT28HC256E-12UM/883 is available at Aetrix Electronics and suitable for avionics boot memory, mission-critical parameter storage, hardened telemetry loggers, and secure configuration vaults requiring stable component supply across extended product lifecycles.

Supply support for AT28HC256E-12UM/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 global semiconductor company specializing in microcontrollers, analog devices, and nonvolatile memory solutions for industrial, automotive, aerospace, and defense markets.

The AT28HC256 product line delivers radiation-tolerant, high-endurance parallel EEPROMs designed specifically for military and space applications demanding guaranteed operation across extreme temperature, shock, and radiation environments.

FAQ

What is the maximum page write cycle time for AT28HC256E-12UM/883?

The AT28HC256E-12UM/883 has a maximum page write cycle time of 10 ms, as specified in the AC Characteristics table (tWC). This applies to all 1–64-byte writes within a single page boundary defined by address bits A6–A14. The device automatically manages internal timing after the first WE pulse, freeing the bus for other operations during the write period.

Does AT28HC256E-12UM/883 support both hardware and software data protection?

Yes, AT28HC256E-12UM/883 implements dual-layer protection: hardware features include VCC sense (inhibits writes below 3.8 V), 5 ms power-on delay, and noise filtering on CE/WE inputs; software protection uses a three-step command sequence (AAh/55h/A0h) to lock the entire array. Both mechanisms operate independently and are active simultaneously in the AT28HC256E-12UM/883.

What package type is used for AT28HC256E-12UM/883?

AT28HC256E-12UM/883 is supplied in a 30-pin Ceramic Pin Grid Array (PGA), conforming to MIL-STD-1835 28U configuration. It features a 2.54 mm pin pitch, ceramic body, and is screened to Class B per MIL-PRF-38535. The part marking "UM/883" explicitly denotes this PGA package with military temperature and screening compliance.

How does DATA polling work on AT28HC256E-12UM/883?

During a write cycle, reading the last written byte from AT28HC256E-12UM/883 causes I/O7 to output the complement of the data until completion. Once the internal programming finishes, I/O7 returns true data-providing a deterministic, interrupt-capable method to detect write end without fixed delays. This behavior is electrically guaranteed across the full –55°C to +125°C range.

Is AT28HC256E-12UM/883 compatible with standard 5V TTL/CMOS logic levels?

Yes, AT28HC256E-12UM/883 has fully TTL- and CMOS-compatible inputs and outputs. Input thresholds meet VIH ≥ 2.0 V and VIL ≤ 0.8 V; output drive strength satisfies VOL ≤ 0.45 V at 6 mA sink and VOH ≥ 2.4 V at 4 mA source-ensuring interoperability with legacy 80C86, Z80, and MIL-STD-1750A systems without level-shifting circuitry.

AT28HC256E-12UM/883 Specifications

Product attributes: Attribute value

Manufacturer:: Microchip Technology

Series:: -

Package/Case:: 28-BCPGA

Packaging:: Box

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:: 120 ns

Voltage - Supply:: 4.5V ~ 5.5V

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

Grade:: -

Qualification:: -

Mounting Type:: Through Hole

Supplier Device Package:: 28-CPGA (13.97x16.51)

AT28HC256E-12UM/883 FAQ

1.How can I place an order for AT28HC256E-12UM/883 through Aetrix?

Please submit a Request for Quotation (RFQ) for AT28HC256E-12UM/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 AT28HC256E-12UM/883 reliable?

The price and inventory of AT28HC256E-12UM/883 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for AT28HC256E-12UM/883 is usually 5 days.

3.What payment methods are accepted for AT28HC256E-12UM/883?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for AT28HC256E-12UM/883 transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for AT28HC256E-12UM/883?

AT28HC256E-12UM/883 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your AT28HC256E-12UM/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 AT28HC256E-12UM/883?

For technical support, including AT28HC256E-12UM/883 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your AT28HC256E-12UM/883 requirements.

6.How does Aetrix verify that AT28HC256E-12UM/883 is sourced from the original manufacturer or authorized distributors?

All AT28HC256E-12UM/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 AT28HC256E-12UM/883 meets industry standards.

7.What is the process for return or replacement of AT28HC256E-12UM/883?

All AT28HC256E-12UM/883 units undergo pre-shipment inspection (PSI). If there is an issue with AT28HC256E-12UM/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 AT28HC256E-12UM/883 part is unused and in its original packaging.

Return procedure for AT28HC256E-12UM/883:

1.Submit a request within 90 days.

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

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