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Microchip Technology AT28HC256-12FM/883
- Part No.:
- AT28HC256-12FM/883
- Manufacturer:
- Microchip Technology
- Category:
- Memory
- Package:
- 28-CFlatPack
- Datasheet:
-
AT28HC256-12FM/883.pdf
- Description:
- IC EEPROM 256KBIT PAR 28FLATPK
- Quantity:
- Payment:
- Shipping:
Inventory:3,832
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Product details
Overview
AT28HC256-12FM/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 AT28HC256-12FM/883 datasheet, AT28HC256-12FM/883 pinout, AT28HC256-12FM/883 application, or AT28HC256-12FM/883 equivalent, this page delivers verified military-spec parameters including endurance (10,000 cycles), CMOS/TTL compatibility, single 5V ±10% supply operation, and 32-lead flatpack packaging with MIL-STD-883 qualification.
Technical Context
The AT28HC256-12FM/883 implements a paged architecture with an internal 64-byte latch enabling simultaneous writes of 1–64 bytes per cycle. Its dual-line chip enable (CE) and output enable (OE) control logic supports bus contention avoidance in multi-master systems without external glue logic.
Write completion is confirmed via I/O7 DATA polling (complement-to-data response) or I/O6 toggle-bit behavior - both operable at any point during tWC. Hardware write inhibition includes VCC sense (<3.8 V), 5 ms power-on delay, noise filtering (<15 ns pulses rejected), and CE/OE/WE state enforcement.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Memory size | 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 - meets timing requirements for direct interface with legacy 80C86/80C186-based controllers operating at ≤8 MHz without wait states. |
| Page write cycle time | 10 ms max - enables efficient field-updatable parameter sets while maintaining deterministic worst-case latency for real-time system recovery sequences. |
| Endurance | 10,000 write/erase cycles - validated for repeated reprogramming in ground-test equipment and flight-software update scenarios over extended service life. |
| Operating temperature | –55°C to +125°C - qualified per MIL-STD-883 Method 1010 for sustained operation in jet engine bays, radar front-ends, and satellite payload compartments. |
| Supply voltage | 5 V ±10% - compatible with standard military power buses and eliminates need for dedicated voltage regulation in SWaP-constrained designs. |
| Standby current | 3 mA (CMOS) - reduces quiescent power draw in always-on subsystems such as inertial navigation backup memory or telemetry event logging buffers. |
Pinout & Package
AT28HC256-12FM/883 is supplied in a 28-lead ceramic flatpack (MIL-STD-1835 F-12 Config B), hermetically sealed and qualified to MIL-STD-883. Pin 1 is marked by chamfered corner; package dimensions: 18.49 mm × 18.08 mm × 3.02 mm (0.728″ × 0.712″ × 0.119″).
| 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 page 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 select; must be low with OE low and WE high for read access; initiates write when paired with WE low. |
| OE | Output Enable | Active-low output gate; controls tri-state buffer; high during write cycles to prevent bus contention. |
| WE | Write Enable | Active-low write strobe; falling edge latches address/data; rising edge triggers internal programming timer. |
| VCC | Power supply | 5 V ±10% main supply; internal VCC sense circuitry inhibits writes below ~3.8 V to prevent corruption during brownout. |
| GND | Ground reference | Signal and power return; decoupling capacitor required within 10 mm of VCC pin per MIL-PRF-38535 Class K layout rules. |
Key Features
| Feature | Design Value |
|---|---|
| Software Data Protection (SDP) | Three-step command sequence (AAh/55h/A0h) enables user-configurable write lock; prevents inadvertent reprogramming during power transitions or EMI events. |
| Hardware Write Inhibition | VCC sense, 5 ms power-on delay, and noise filtering eliminate need for external reset supervisors or RC timing circuits in ruggedized designs. |
| Page Write Architecture | Internal 64-byte latch allows burst loading of configuration blocks - reduces host CPU overhead by >85% vs. byte-by-byte writes in telemetry logging applications. |
| DATA Polling & Toggle Bit | Dual asynchronous write-completion detection methods provide flexibility for interrupt-driven or polling-based firmware architectures without requiring external status lines. |
| Military Temperature Range | Full functionality across –55°C to +125°C ensures reliable operation in unheated airborne electronics bays and high-temperature vehicle-mounted computing modules. |
Applications
| Avionics Boot Memory | Missile Guidance Calibration Storage |
|---|---|
Use Scenario: Stores FPGA configuration bitstreams and microcontroller boot firmware in fly-by-wire flight control computers. IC Role / Device Role / Timing Role: Nonvolatile program memory accessed during cold-start initialization; requires guaranteed read reliability at –40°C and <120 ns access for deterministic boot timing. Use Value: JEDEC pinout enables drop-in replacement of legacy EPROMs; 10,000-cycle endurance supports field updates of flight software between maintenance cycles. | Use Scenario: Retains gyro bias compensation coefficients and seeker alignment parameters in tactical missile guidance sections exposed to extreme thermal cycling. IC Role / Device Role / Timing Role: High-reliability data retention element; operates continuously at +125°C inside seeker housings during pre-launch standby and powered flight phases. Use Value: 10-year data retention and MIL-STD-883 qualification ensure parameter integrity across 15+ year stockpile lifetimes without periodic refresh. |
| Secure Communications Key Storage | Ruggedized Test Equipment Configuration |
Use Scenario: Holds cryptographic key material and secure boot certificates in NSA-certified Type 1 encryption modules deployed in battlefield radios. IC Role / Device Role / Timing Role: Tamper-resistant nonvolatile storage with hardware/software write protection; prevents unauthorized modification during physical handling or voltage glitch attacks. Use Value: SDP lockout and VCC-sense inhibition block write attempts during battery insertion or transient power faults - critical for FIPS 140-2 Level 3 compliance. | Use Scenario: Stores instrument calibration constants and user-defined test profiles in portable MIL-STD-461G emissions analyzers used on aircraft carrier decks. IC Role / Device Role / Timing Role: Field-updatable configuration memory; withstands shock (100 g), vibration (10–2,000 Hz), and salt fog per MIL-STD-810H. Use Value: Ceramic flatpack package resists mechanical stress and moisture ingress; page write capability enables rapid recalibration uploads via RS-232 without interrupting instrument operation. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar EEPROM applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| AT28HC256-12JM/883 | Same die, 32-lead CERDIP package instead of 28-lead flatpack; identical electrical specs and MIL-STD-883 screening. | Requires PCB redesign due to different footprint, lead count, and thermal mass; preferred where higher pin count enables routing flexibility or legacy board reuse. | Select when existing CERDIP socket infrastructure exists or when enhanced thermal dissipation is needed in conduction-cooled assemblies. |
| DS2502-E48+T&R | 1-Wire serial EEPROM (48-bit ID + 1024-bit user memory); no parallel interface, no page write, no military temp range (–40°C to +85°C only). | Used for simple device identification or small-parameter storage; incompatible with parallel bus systems requiring byte-addressable random access. | Choose only for low-pin-count, low-bandwidth identity tagging - not a functional substitute for AT28HC256-12FM/883's parallel architecture or military environmental performance. |
Compared with AT28HC256-12JM/883, the AT28HC256-12FM/883 offers identical functionality in a smaller 28-lead flatpack footprint ideal for space-constrained avionics modules, while DS2502-E48+T&R lacks parallel interface, page write, and military temperature support - making it unsuitable for high-reliability, high-speed firmware storage applications.
Availability
AT28HC256-12FM/883 is available at Aetrix Electronics and suitable for avionics boot memory, missile guidance calibration storage, and secure communications key storage requiring stable component supply under extended lead times and strict traceability protocols.
Supply support for AT28HC256-12FM/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 memory solutions, with a strong heritage in military and aerospace components acquired through Atmel.
The AT28HC256 product line was designed for high-reliability, radiation-tolerant nonvolatile storage in defense electronics where long-term data retention, deterministic write timing, and immunity to power-supply transients are mandatory.
FAQ
What is the maximum page write cycle time for AT28HC256-12FM/883?
The AT28HC256-12FM/883 has a maximum page write cycle time of 10 ms, as specified in the AC characteristics table for the -12 speed grade. This value applies across the full military temperature range (–55°C to +125°C) and is guaranteed under worst-case VCC (4.5 V) and temperature conditions. The AT28HC256-12FM/883 achieves this using an internal control timer that automatically manages the programming sequence after data latching.
Does AT28HC256-12FM/883 support both hardware and software data protection?
Yes, AT28HC256-12FM/883 implements dual-layer data protection: hardware features include VCC sensing (<3.8 V), 5 ms power-on delay, and noise filtering on CE/WE inputs; software protection uses a three-byte command sequence (AAh/55h/A0h) to enable/disable write locking. Both mechanisms operate independently and concurrently - the AT28HC256-12FM/883 remains protected even if one layer fails.
What package type is used for AT28HC256-12FM/883?
AT28HC256-12FM/883 is packaged in a 28-lead ceramic flatpack (MIL-STD-1835 F-12 Config B), hermetically sealed and qualified per MIL-STD-883. The "FM" suffix explicitly denotes this flatpack configuration, distinguishing it from CERDIP (JM), CLCC (LM), or PGA (UM) variants. Pin 1 is identified by a chamfered corner per standard marking convention.
How is write completion detected on AT28HC256-12FM/883?
AT28HC256-12FM/883 supports two independent write-completion detection methods: DATA polling (monitoring complement-to-data on I/O7) and toggle-bit detection (observing I/O6 toggling state). Either method can be initiated at any time during the write cycle - no fixed delay or polling interval is required. Once valid data appears on all outputs, the AT28HC256-12FM/883 is ready for the next access.
Is AT28HC256-12FM/883 compatible with standard TTL and CMOS logic levels?
Yes, AT28HC256-12FM/883 features CMOS and TTL 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. This ensures interoperability with legacy 80Cxx microcontrollers, FPGAs, and discrete logic families without level-shifting circuitry.
AT28HC256-12FM/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:
- 120 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
AT28HC256-12FM/883 FAQ
1.How can I place an order for AT28HC256-12FM/883 through Aetrix?
Please submit a Request for Quotation (RFQ) for AT28HC256-12FM/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 AT28HC256-12FM/883 reliable?
The price and inventory of AT28HC256-12FM/883 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for AT28HC256-12FM/883 is usually 5 days.
3.What payment methods are accepted for AT28HC256-12FM/883?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for AT28HC256-12FM/883 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for AT28HC256-12FM/883?
AT28HC256-12FM/883 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your AT28HC256-12FM/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 AT28HC256-12FM/883?
For technical support, including AT28HC256-12FM/883 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your AT28HC256-12FM/883 requirements.
6.How does Aetrix verify that AT28HC256-12FM/883 is sourced from the original manufacturer or authorized distributors?
All AT28HC256-12FM/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 AT28HC256-12FM/883 meets industry standards.
7.What is the process for return or replacement of AT28HC256-12FM/883?
All AT28HC256-12FM/883 units undergo pre-shipment inspection (PSI). If there is an issue with AT28HC256-12FM/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 AT28HC256-12FM/883 part is unused and in its original packaging.
Return procedure for AT28HC256-12FM/883:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
AT28HC256-12FM/883 Tags
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