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Microchip Technology AT28HC256F-90DM/883

Name: AT28HC256F-90DM/883
Brand: Microchip Technology
SKU: AT28HC256F-90DM/883
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: AT28HC256F-90DM/883

Manufacturer:: Microchip Technology

Category:: Memory

Package:: 28-CDIP (0.600", 15.24mm)

Datasheet:: AT28HC256F-90DM/883.pdf

Description:: IC EEPROM 256KBIT PAR 28CERDIP

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Product details

Overview

AT28HC256F-90DM/883 from Microchip Technology is a military-grade 256-Kbit (32,768 × 8) paged parallel EEPROM with 90 ns read access time, 3 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. Used in avionics control modules for nonvolatile configuration storage requiring radiation-tolerant, long-retention memory.

For engineers reviewing the AT28HC256F-90DM/883 datasheet, AT28HC256F-90DM/883 pinout, AT28HC256F-90DM/883 application, or AT28HC256F-90DM/883 equivalent, this page delivers verified military-spec timing, endurance (10,000 cycles), power behavior (80 mA active / 300 µA CMOS standby), and package-specific pin validation for CERDIP/CLCC/FLATPACK/PGA variants.

Technical Context

The AT28HC256F-90DM/883 implements a paged architecture with a 64-byte internal latch, enabling simultaneous write of 1–64 bytes within a single page defined by address bits A6–A14. Its dual-line chip enable (CE) and output enable (OE) control supports bus contention avoidance in multiprocessor systems.

Write operations are governed by an internal control timer; completion is signaled via I/O7 DATA polling or I/O6 toggle-bit behavior. Hardware protection includes VCC sense (<3.8 V inhibits writes), 5 ms power-on delay, noise filtering (<15 ns pulses ignored), and write-inhibit logic (OE low, CE high, or WE high).

Key Specifications

Parameter	Value and Actual Design Meaning
Memory size	256 Kbit (32,768 × 8) - provides sufficient space for boot code, calibration tables, and fault logs in embedded military systems.
Read access time	90 ns - enables direct replacement of SRAM in legacy MIL-STD-1553 or ARINC-429 interface controllers without timing redesign.
Page write cycle time	3 ms max - reduces firmware update latency vs. 10 ms standard variant, critical for field-programmable mission profiles.
Endurance	10,000 write/erase cycles - validated for repeated reconfiguration in ground support equipment and flight test instrumentation.
Data retention	10 years at +125°C - meets MIL-PRF-38535 Class B requirements for unpowered storage in sealed avionics enclosures.
Supply voltage	5 V ±10% - compatible with legacy 5 V TTL/CMOS logic families without level-shifting circuitry.
Operating temperature	–55°C to +125°C - qualified per MIL-STD-883 Method 1010 for extended thermal cycling in missile guidance subsystems.

Pinout & Package

AT28HC256F-90DM/883 is supplied in 32-lead CERDIP, 32-lead CLCC, 32-lead FLATPACK, and 30-pin PGA packages. Pin functions are identical across all variants per JEDEC byte-wide standard; pin 1 orientation and mechanical dimensions differ per package type.

Pin/Terminal	Circuit Role	Design Meaning
A0–A14	Address inputs	15-bit address bus supporting full 32,768-word addressing; A6–A14 define page boundaries for 64-byte write operations.
I/O0–I/O7	Bidirectional data bus	CMOS/TTL-compatible 8-bit parallel interface; I/O7 used for DATA polling, I/O6 for toggle-bit write status indication.
CE	Chip Enable	Active-low device select; must be low with OE low and WE high for read access; initiates write when low with OE high and WE low.
OE	Output Enable	Active-low output gate; controls data bus drive during reads; high during writes to prevent bus contention.
WE	Write Enable	Active-low write strobe; falling edge latches address/data; rising edge triggers internal write timer and page programming sequence.
VCC	Power supply	+5 V ±10% primary supply; internal VCC sense circuitry disables writes below ~3.8 V to prevent corruption during brownout.
GND	Ground reference	Signal and power return path; decoupling capacitor placement near pin 14 (CERDIP) or pin 16 (CLCC) required for stable 90 ns timing.
NC / DC	No-connect / Don't connect	Pins marked NC or DC (e.g., CLCC pins 1 & 17) must remain unconnected; floating these pins prevents parasitic coupling in high-noise EMI environments.

Key Features

Feature	Design Value
64-byte page register	Enables burst writes without external address sequencing logic - reduces MCU GPIO overhead and firmware complexity in telemetry recorders.
DATA Polling (I/O7)	Provides deterministic, clock-synchronous write completion detection - eliminates need for fixed-delay loops or external timers in real-time OS tasks.
Toggle Bit (I/O6)	Offers asynchronous, interrupt-driven write status monitoring - allows CPU to perform other tasks while waiting for EEPROM programming to finish.
Software Data Protection (SDP)	Three-byte command sequence (AAh/55h/A0h) enables/disable write lock - prevents accidental overwrites during power-up transients in airborne power management units.
Extra 64-byte ID area	Accessible via A9 = 12 V ±0.5 V at addresses 7FC0h–7FFFh - stores unique unit serial numbers, calibration coefficients, or firmware version stamps traceable to MIL-STD-130.

Applications

Avionics Boot Memory	Mission Data Logger
Use Scenario: Stores bootloader firmware and FPGA configuration bitstreams in radar signal processors deployed on fighter aircraft. IC Role / Device Role / Timing Role: Nonvolatile storage element interfaced directly to a 5 V Z80 or 80C86 host processor; operates as memory-mapped peripheral with static RAM timing compatibility. Use Value: 90 ns access ensures no wait states added to CPU instruction fetch; 10-year data retention guarantees integrity across multi-year depot maintenance cycles without battery backup.	Use Scenario: Captures sensor fusion outputs and GPS timestamps in unmanned aerial vehicle (UAV) flight control units during extended missions. IC Role / Device Role / Timing Role: Page-write buffer for burst-mode logging; leverages 3 ms page write to capture 64 samples before next sensor acquisition window. Use Value: Hardware write protection prevents corruption during engine vibration-induced power glitches; –55°C to +125°C rating sustains operation inside unheated wing-mounted pods.
Weapons System Calibration Store	Tactical Radio Configuration
Use Scenario: Holds weapon alignment offsets, laser rangefinder compensation tables, and fuse timing parameters in guided munition guidance sections. IC Role / Device Role / Timing Role: Secure, tamper-resistant configuration store accessed only during pre-launch initialization; SDP enabled after final calibration. Use Value: 10,000-cycle endurance exceeds expected field recalibration frequency; extra 64-byte ID area encodes lot traceability per DFARS 252.211-7003 requirements.	Use Scenario: Stores cryptographic key slots, frequency hopping sequences, and user-defined channel maps in handheld SINCGARS radios. IC Role / Device Role / Timing Role: Low-power configuration manager; enters <300 µA CMOS standby mode between radio channel changes to extend battery life. Use Value: JEDEC pinout ensures drop-in replacement of legacy 27C256 EPROMs in existing PCBs; 5 V tolerance simplifies integration with discrete transistor-level interface circuits.

Avionics Boot Memory

Mission Data Logger

Use Scenario: Stores bootloader firmware and FPGA configuration bitstreams in radar signal processors deployed on fighter aircraft.

IC Role / Device Role / Timing Role: Nonvolatile storage element interfaced directly to a 5 V Z80 or 80C86 host processor; operates as memory-mapped peripheral with static RAM timing compatibility.

Use Value: 90 ns access ensures no wait states added to CPU instruction fetch; 10-year data retention guarantees integrity across multi-year depot maintenance cycles without battery backup.

Use Scenario: Captures sensor fusion outputs and GPS timestamps in unmanned aerial vehicle (UAV) flight control units during extended missions.

IC Role / Device Role / Timing Role: Page-write buffer for burst-mode logging; leverages 3 ms page write to capture 64 samples before next sensor acquisition window.

Use Value: Hardware write protection prevents corruption during engine vibration-induced power glitches; –55°C to +125°C rating sustains operation inside unheated wing-mounted pods.

Weapons System Calibration Store

Tactical Radio Configuration

Use Scenario: Holds weapon alignment offsets, laser rangefinder compensation tables, and fuse timing parameters in guided munition guidance sections.

IC Role / Device Role / Timing Role: Secure, tamper-resistant configuration store accessed only during pre-launch initialization; SDP enabled after final calibration.

Use Value: 10,000-cycle endurance exceeds expected field recalibration frequency; extra 64-byte ID area encodes lot traceability per DFARS 252.211-7003 requirements.

Use Scenario: Stores cryptographic key slots, frequency hopping sequences, and user-defined channel maps in handheld SINCGARS radios.

IC Role / Device Role / Timing Role: Low-power configuration manager; enters <300 µA CMOS standby mode between radio channel changes to extend battery life.

Use Value: JEDEC pinout ensures drop-in replacement of legacy 27C256 EPROMs in existing PCBs; 5 V tolerance simplifies integration with discrete transistor-level interface circuits.

Equivalent & Alternatives

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

Alternative Part	Technical Difference	Application Difference	Selection Advice
AT28HC256-12DM/883	120 ns read access time; 10 ms page write cycle; same endurance and temperature range.	Suitable for cost-sensitive ground-based test equipment where timing margin allows slower access.	Select when system timing budget permits >90 ns latency and longer firmware update windows are acceptable.
DS2502-E48+T&R	1-Wire serial interface; 1024-bit EEPROM; industrial temp (–40°C to +85°C); no page write or polling.	Used in asset tracking tags and simple sensor nodes where pin count and board space are constrained.	Choose only for new designs prioritizing minimal interconnect; not a functional or pinout substitute for AT28HC256F-90DM/883.

Compared with AT28HC256-12DM/883, the AT28HC256F-90DM/883 delivers 33% faster read access and 3× faster page writes-critical for real-time avionics response. Versus DS2502-E48+T&R, it offers parallel bandwidth, military temperature compliance, and deterministic write signaling absent in 1-Wire protocols.

Availability

AT28HC256F-90DM/883 is available at Aetrix Electronics and suitable for avionics boot memory, mission data loggers, weapons calibration stores, and tactical radio configuration requiring stable component supply under MIL-PRF-38535 Class B sourcing.

Supply support for AT28HC256F-90DM/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 aerospace, defense, and industrial markets.

The AT28HC256 product line was developed to deliver radiation-tolerant, high-reliability parallel EEPROMs for legacy 5 V system upgrades and MIL-STD-1553 bus controllers requiring deterministic, page-optimized nonvolatile storage.

FAQ

What is the guaranteed minimum endurance rating for AT28HC256F-90DM/883?

The AT28HC256F-90DM/883 is rated for 10,000 write/erase cycles per memory location under full military temperature conditions (–55°C to +125°C). This endurance is validated per MIL-STD-883 Method 1008 and applies to both byte and page write operations. The device also supports optional extended endurance (100,000 cycles) in non-military variants, but AT28HC256F-90DM/883 specifically guarantees 10,000 cycles.

Does AT28HC256F-90DM/883 require external high-voltage programming circuitry?

No, AT28HC256F-90DM/883 operates from a single 5 V ±10% supply and requires no external high-voltage programming signals. All write and erase functions-including software chip erase-are executed using standard 5 V logic levels. The optional 12 V signal on A9 is used exclusively for accessing the 64-byte device identification area, not for main array programming.

How is write completion detected on AT28HC256F-90DM/883?

AT28HC256F-90DM/883 supports two hardware-confirmed methods: DATA Polling on I/O7 (complement of last written byte appears until write completes) and Toggle Bit on I/O6 (toggles between 0 and 1 during write, then stabilizes). Both methods are valid at any point during the write cycle and eliminate reliance on fixed delays or external timers.

Which packages are available for AT28HC256F-90DM/883?

AT28HC256F-90DM/883 is offered in four hermetically sealed military packages: 32-lead CERDIP (MIL-STD-1835 D-10), 32-lead CLCC (MIL-STD-1835 C-12), 32-lead FLATPACK (MIL-STD-1835 F-12), and 30-pin PGA (MIL-STD-1835 U-12). All share identical pin functions and electrical specifications; mechanical drawings and marking formats are documented in Microchip DS20006352A.

Is software data protection (SDP) enabled by default on AT28HC256F-90DM/883?

No, AT28HC256F-90DM/883 ships with software data protection disabled. SDP must be explicitly enabled using the three-byte command sequence (AAh to 5555h, 55h to 2AAAh, A0h to 5555h). Once enabled, SDP remains active through power cycles and requires the disable sequence (AAh/55h/80h/AAh/20h/55h/2AAAh) to deactivate. The AT28HC256F-90DM/883 supports full SDP functionality per datasheet Section 6.11–6.12.

AT28HC256F-90DM/883 Specifications

Product attributes: Attribute value

Manufacturer:: Microchip Technology

Series:: -

Package/Case:: 28-CDIP (0.600", 15.24mm)

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:: 3ms

Access Time:: 90 ns

Voltage - Supply:: 4.5V ~ 5.5V

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

Grade:: -

Qualification:: -

Mounting Type:: Through Hole

Supplier Device Package:: 28-CerDip

AT28HC256F-90DM/883 FAQ

1.How can I place an order for AT28HC256F-90DM/883 through Aetrix?

Please submit a Request for Quotation (RFQ) for AT28HC256F-90DM/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 AT28HC256F-90DM/883 reliable?

The price and inventory of AT28HC256F-90DM/883 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for AT28HC256F-90DM/883 is usually 5 days.

3.What payment methods are accepted for AT28HC256F-90DM/883?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for AT28HC256F-90DM/883 transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for AT28HC256F-90DM/883?

AT28HC256F-90DM/883 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your AT28HC256F-90DM/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 AT28HC256F-90DM/883?

For technical support, including AT28HC256F-90DM/883 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your AT28HC256F-90DM/883 requirements.

6.How does Aetrix verify that AT28HC256F-90DM/883 is sourced from the original manufacturer or authorized distributors?

All AT28HC256F-90DM/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 AT28HC256F-90DM/883 meets industry standards.

7.What is the process for return or replacement of AT28HC256F-90DM/883?

All AT28HC256F-90DM/883 units undergo pre-shipment inspection (PSI). If there is an issue with AT28HC256F-90DM/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 AT28HC256F-90DM/883 part is unused and in its original packaging.

Return procedure for AT28HC256F-90DM/883:

1.Submit a request within 90 days.

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

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