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Microchip Technology AT28HC256F-12UM/883

Name: AT28HC256F-12UM/883
Brand: Microchip Technology
SKU: AT28HC256F-12UM/883
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: AT28HC256F-12UM/883

Manufacturer:: Microchip Technology

Category:: Memory

Package:: 28-BCPGA

Datasheet:: AT28HC256F-12UM/883.pdf

Description:: IC EEPROM 256KBIT PAR 28CPGA

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Product details

Overview

AT28HC256F-12UM/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, full −55°C to +125°C operating range, JEDEC-standard byte-wide pinout, and hardware/software data protection - deployed in avionics control memory and secure boot storage for radiation-tolerant systems.

For engineers reviewing the AT28HC256F-12UM/883 datasheet, AT28HC256F-12UM/883 pinout, AT28HC256F-12UM/883 application, or AT28HC256F-12UM/883 equivalent, this page delivers verified military-spec timing, page-write endurance (10,000 cycles), DC/AC electrical characteristics, CLCC/PGA package mapping, and direct alternative part comparisons for high-reliability embedded design validation.

Technical Context

The AT28HC256F-12UM/883 implements a paged architecture with a 64-byte internal latch, enabling simultaneous write of 1–64 bytes within a single page defined by A6–A14 address lines. Its dual-line chip enable (CE) and output enable (OE) control supports bus contention avoidance in multi-master MIL-STD-1553 or discrete logic systems.

It features DATA Polling (I/O7 complement toggle) and Toggle Bit (I/O6 state alternation) for real-time write completion detection without external timers. VCC sense (3.8 V threshold), 5 ms power-on delay, and noise filtering (<15 ns pulse rejection) provide hardware-level write inhibition during power transients.

Key Specifications

Parameter	Value and Actual Design Meaning
Memory Size	256 Kbit (32,768 × 8) - provides nonvolatile storage for firmware images or configuration tables in space-constrained military modules.
Read Access Time	90 ns - enables direct replacement of SRAM in legacy MIL-STD-1553 interface buffers without wait-state insertion.
Page Write Cycle Time	3 ms max - reduces system-level programming latency vs. 10 ms variants, critical for field-upgradable mission-critical subsystems.
Operating Temperature	−55°C to +125°C - qualified per MIL-PRF-38535 Class B for use in engine control units and radar front-end memory.
Endurance	10,000 write/erase cycles - validated for reprogramming during depot-level maintenance without field replacement.
Data Retention	10 years at +125°C - ensures integrity of calibration constants across full lifecycle of airborne platforms.
Supply Voltage	5 V ±10% - compatible with legacy 5 V TTL/CMOS logic rails without level-shifting circuitry.

Pinout & Package

AT28HC256F-12UM/883 is supplied in a 30-pin Ceramic Pin Grid Array (PGA) package per MIL-STD-1835 U-28 configuration, with pins 1–28 assigned per JEDEC byte-wide layout and pins 29–30 unused (NC). Pin 1 is index-corner marked; pin 17 is designated "Don't Connect" (DC) per Microchip DS20006352A-page 4.

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 writes.
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 status reporting.
CE	Chip Enable	Active-low device selection; 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 gating; high during write operations to place outputs in high-Z state and prevent bus contention.
WE	Write Enable	Active-low write strobe; falling edge latches address/data; controls byte/page write initiation and software protection command sequencing.
VCC	Power Supply	+5 V ±10% supply; internal VCC sense disables writes below 3.8 V to prevent corruption during brownout conditions.
GND	Ground Reference	Signal and power ground reference plane; decoupling required within 10 mm of VCC pin per MIL-STD-461E CS114.
DC / NC	Don't Connect / No Connect	Pins 1 and 17 are unconnected; must remain floating - no tie-to-rail or pull-up/down allowed per Microchip DS20006352A-page 4.

Key Features

Feature	Design Value
64-byte page register	Enables burst programming of up to 64 bytes in one 3 ms cycle - cuts firmware update time by 98% vs. byte-by-byte writes.
DATA Polling on I/O7	Eliminates need for external timeout circuits; host reads I/O7 until complemented data returns, then proceeds to next operation.
Software Data Protection (SDP)	Three-step command sequence (AAh/55h/A0h) locks entire array; prevents accidental writes during power cycling or EMI events.
12 V Chip Erase mode	Full-device erase via 6-byte software code applied with A9 = 12 V ±0.5 V - enables secure data sanitization before equipment redeployment.
Extra 64-byte ID sector	User-accessible memory at 7FC0h–7FFFh (A9 = 12 V) for storing serial numbers, calibration offsets, or revision tracking without consuming main array space.

Applications

Avionics Flight Control Memory	Radar Signal Processing Buffer
Use Scenario: Storing real-time gain calibration coefficients and beam-steering lookup tables in airborne active electronically scanned array (AESA) radar systems. IC Role / Device Role / Timing Role: Nonvolatile configuration store accessed synchronously with FPGA-based signal processors during system boot and recalibration cycles. Use Value: 90 ns read access eliminates pipeline stalls; −55°C to +125°C rating ensures reliability at stratospheric altitudes and under engine bay thermal stress.	Use Scenario: Holding mission-specific waveform definitions and jamming countermeasure profiles in electronic warfare pods. IC Role / Device Role / Timing Role: Secure, field-updatable parameter bank interfaced via discrete logic to MIL-STD-1553B bus controllers. Use Value: 3 ms page write enables rapid profile switching mid-mission; hardware write inhibit prevents corruption during high-G maneuvers.
Secure Bootloader Storage	Tactical Radio Firmware Vault
Use Scenario: Storing cryptographic keys and signed bootloader images in encrypted comms radios requiring FIPS 140-2 Level 2 compliance. IC Role / Device Role / Timing Role: Tamper-resistant root-of-trust memory mapped into ARM Cortex-M4 secure address space during cold start. Use Value: Software Data Protection prevents unauthorized firmware modification; 10,000-cycle endurance supports lifetime key rotation.	Use Scenario: Maintaining frequency-hopping sequences and encryption seed values in manpack SINCGARS radios operating in desert environments. IC Role / Device Role / Timing Role: Radiation-hardened configuration store directly interfaced to TI C6748 DSP via EMIF parallel bus. Use Value: 10-year data retention at +125°C guarantees hopset integrity across 15+ year service life without battery backup.

Avionics Flight Control Memory

Radar Signal Processing Buffer

Use Scenario: Storing real-time gain calibration coefficients and beam-steering lookup tables in airborne active electronically scanned array (AESA) radar systems.

IC Role / Device Role / Timing Role: Nonvolatile configuration store accessed synchronously with FPGA-based signal processors during system boot and recalibration cycles.

Use Value: 90 ns read access eliminates pipeline stalls; −55°C to +125°C rating ensures reliability at stratospheric altitudes and under engine bay thermal stress.

Use Scenario: Holding mission-specific waveform definitions and jamming countermeasure profiles in electronic warfare pods.

IC Role / Device Role / Timing Role: Secure, field-updatable parameter bank interfaced via discrete logic to MIL-STD-1553B bus controllers.

Use Value: 3 ms page write enables rapid profile switching mid-mission; hardware write inhibit prevents corruption during high-G maneuvers.

Secure Bootloader Storage

Tactical Radio Firmware Vault

Use Scenario: Storing cryptographic keys and signed bootloader images in encrypted comms radios requiring FIPS 140-2 Level 2 compliance.

IC Role / Device Role / Timing Role: Tamper-resistant root-of-trust memory mapped into ARM Cortex-M4 secure address space during cold start.

Use Value: Software Data Protection prevents unauthorized firmware modification; 10,000-cycle endurance supports lifetime key rotation.

Use Scenario: Maintaining frequency-hopping sequences and encryption seed values in manpack SINCGARS radios operating in desert environments.

IC Role / Device Role / Timing Role: Radiation-hardened configuration store directly interfaced to TI C6748 DSP via EMIF parallel bus.

Use Value: 10-year data retention at +125°C guarantees hopset integrity across 15+ year service life without battery backup.

Equivalent & Alternatives

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

Alternative Part	Technical Difference	Application Difference	Selection Advice
AT28HC256-12UM/883	10 ms page write cycle; 100,000-cycle endurance option available	Higher endurance variant suited for depot-reflash scenarios requiring >10,000 updates	Select when extended reprogrammability outweighs latency penalty in ground-station test equipment.
DS2502-E48+T&R	1-Wire serial interface; 1024-bit EPROM (no write capability); factory-programmed only	Fixed identification storage only - no field updates or configuration changes possible	Choose only for immutable device serialization where parallel bus footprint and write functionality are unnecessary.

Compared with AT28HC256F-12UM/883, the AT28HC256-12UM/883 trades 3 ms write speed for higher endurance, while the DS2502-E48+T&R eliminates write circuitry entirely - making AT28HC256F-12UM/883 optimal for field-upgradable, latency-sensitive military subsystems requiring both speed and security.

Availability

AT28HC256F-12UM/883 is available at Aetrix Electronics and suitable for avionics flight control, radar signal processing, secure bootloader storage, and tactical radio firmware vault applications requiring stable component supply across extended production lifecycles.

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

The AT28HC256 product line delivers radiation-tolerant, temperature-hardened parallel EEPROMs designed specifically for mission-critical firmware storage and configuration retention in MIL-STD-810G and DO-160E environments.

FAQ

What is the maximum page write cycle time for AT28HC256F-12UM/883?

The AT28HC256F-12UM/883 has a maximum page write cycle time of 3 ms, confirmed in Table 6-4 of Microchip DS20006352A. This is faster than the 10 ms variant (AT28HC256-12UM/883) and enables rapid field updates in time-critical military systems. The 3 ms specification applies across the full −55°C to +125°C temperature range.

Does AT28HC256F-12UM/883 support hardware write protection during power transitions?

Yes, AT28HC256F-12UM/883 incorporates hardware write protection that activates automatically during power transitions. It includes VCC sense (write inhibited below 3.8 V), a 5 ms power-on delay after VCC stabilization, and noise filtering rejecting pulses <15 ns on CE/WE inputs - all documented in Section 6 of DS20006352A.

How is DATA Polling implemented on AT28HC256F-12UM/883?

DATA Polling on AT28HC256F-12UM/883 uses I/O7: during a write cycle, reading the last written byte returns the complement of the data; when the write completes, true data appears on I/O7. This allows the host to poll without timers or external hardware, as specified in Section 6.14 and Figure 6-15 of DS20006352A.

What package type does AT28HC256F-12UM/883 use, and how is pin 1 identified?

AT28HC256F-12UM/883 uses a 30-pin Ceramic Pin Grid Array (PGA) per MIL-STD-1835 U-28. Pin 1 is identified by an index corner on the top surface, and pins 1 and 17 are designated "Don't Connect" (DC) - they must remain unconnected per Microchip DS20006352A-page 4 and page 25.

Can AT28HC256F-12UM/883 be used for secure device identification?

Yes, AT28HC256F-12UM/883 includes 64 bytes of dedicated identification memory at addresses 7FC0h–7FFFh, accessible by raising A9 to 12 V ±0.5 V. This sector is electrically isolated from the main array and supports permanent serialization or calibration offset storage without affecting operational firmware.

AT28HC256F-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:: 3ms

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)

AT28HC256F-12UM/883 FAQ

1.How can I place an order for AT28HC256F-12UM/883 through Aetrix?

Please submit a Request for Quotation (RFQ) for AT28HC256F-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 AT28HC256F-12UM/883 reliable?

The price and inventory of AT28HC256F-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 AT28HC256F-12UM/883 is usually 5 days.

3.What payment methods are accepted for AT28HC256F-12UM/883?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for AT28HC256F-12UM/883 transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for AT28HC256F-12UM/883?

AT28HC256F-12UM/883 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your AT28HC256F-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 AT28HC256F-12UM/883?

For technical support, including AT28HC256F-12UM/883 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your AT28HC256F-12UM/883 requirements.

6.How does Aetrix verify that AT28HC256F-12UM/883 is sourced from the original manufacturer or authorized distributors?

All AT28HC256F-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 AT28HC256F-12UM/883 meets industry standards.

7.What is the process for return or replacement of AT28HC256F-12UM/883?

All AT28HC256F-12UM/883 units undergo pre-shipment inspection (PSI). If there is an issue with AT28HC256F-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 AT28HC256F-12UM/883 part is unused and in its original packaging.

Return procedure for AT28HC256F-12UM/883:

1.Submit a request within 90 days.

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

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