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Microchip Technology AT28C256-25FM/883
- Part No.:
- AT28C256-25FM/883
- Manufacturer:
- Microchip Technology
- Category:
- Memory
- Package:
- 28-CFlatPack
- Datasheet:
-
AT28C256-25FM/883.pdf
- Description:
- IC EEPROM 256KBIT PAR 28FLATPK
- Quantity:
- Payment:
- Shipping:
Inventory:4,415
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Product details
Overview
AT28C256-25FM/883 from Microchip Technology is a military-grade paged parallel EEPROM with 256-Kbit (32,768 × 8) organization, 250 ns read access time, single 5V ±10% supply operation, and JEDEC-approved byte-wide pinout. It supports 1–64-byte page writes with 10 ms max write cycle time and delivers 300 µA CMOS standby current for low-power embedded systems requiring nonvolatile storage in harsh environments.
For engineers reviewing the AT28C256-25FM/883 datasheet, AT28C256-25FM/883 pinout, AT28C256-25FM/883 application, or AT28C256-25FM/883 equivalent, this device serves as a drop-in replacement for legacy parallel EEPROMs in avionics, defense computing, and space-qualified instrumentation where MIL-STD-883 compliance, data retention ≥10 years, and 10,000 write cycles are mandatory.
Technical Context
The AT28C256-25FM/883 implements a paged architecture with an internal 64-byte latch enabling burst writes without bus hold. Its dual-line control (CE/OE) allows flexible bus contention management during read operations, while hardware write inhibit-via VCC sense (3.8 V threshold), 5 ms power-on delay, and noise filtering (<15 ns)-ensures immunity to system-level transients.
Data integrity is enforced through DATA Polling (I/O7 complement feedback) and Toggle Bit (I/O6 toggling) mechanisms for real-time write completion detection. Software Data Protection (SDP) uses a 3-byte command sequence (AAh/55h/A0h) to enable/disable write lock, and optional chip erase is supported via 6-byte software code with 12 V on A9.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Memory size | 256 Kbit (32,768 × 8) - fixed byte-addressable array for firmware storage and configuration retention |
| Read access time | 250 ns max - meets timing requirements for 4 MHz synchronous bus interfaces in MIL-STD-1553 or ARINC-429 subsystems |
| Page write cycle | 10 ms max - enables efficient firmware patching with up to 64 bytes per write without external timing circuitry |
| Endurance | 10,000 write/erase cycles - validated under MIL-STD-883 Method 1012 for mission-critical field updates |
| Data retention | 10 years at +125°C - guaranteed retention across full military temperature range (-55°C to +125°C) |
| Supply voltage | 5 V ±10% - compatible with legacy 5 V TTL/CMOS logic families without level-shifting |
| Standby current | 300 µA CMOS - enables ultra-low quiescent power in always-on avionics modules |
Pinout & Package
AT28C256-25FM/883 is supplied in a 28-lead flatpack package compliant with MIL-STD-1835 F-12 Config B, featuring ceramic hermetic sealing and gold-plated leads for high-reliability aerospace deployment.
| 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 | Byte-wide parallel interface; I/O7 provides DATA Polling status, I/O6 provides Toggle Bit status during write cycles |
| CE | Chip Enable | Active-low selection signal; must be stable before address setup; enables hardware write inhibit when high |
| OE | Output Enable | Active-low output control; places I/O pins in high-impedance state when high to prevent bus contention |
| WE | Write Enable | Active-low write strobe; falling edge latches address/data; combined with CE/OE defines all operating modes per Table 6-1 |
| VCC | Power supply | +5 V ±10% input; internal VCC sense disables writes below 3.8 V to prevent corruption during brownout |
| GND | Ground reference | Signal and power return path; decoupling capacitor required within 10 mm of VCC/GND pins per MIL-PRF-38535 |
Key Features
| Feature | Design Value |
|---|---|
| JEDEC byte-wide pinout | Direct compatibility with industry-standard memory controllers and legacy board layouts without redesign |
| Hardware write protection | VCC sensing, 5 ms power-on delay, and 15 ns noise filtering eliminate need for external reset supervisors or RC timers |
| DATA Polling & Toggle Bit | Real-time, bus-compatible write completion detection without requiring dedicated status lines or polling overhead |
| Software Data Protection (SDP) | User-configurable 3-byte command lock prevents accidental writes during power transitions or firmware updates |
| Device identification area | 64-byte reserved EEPROM block (7FC0H–7FFFH) accessible with 12 V on A9 for serialization and traceability |
Applications
| Avionics Flight Control | Military Communications |
|---|---|
Use Scenario: Storing flight control law parameters and sensor calibration coefficients in fly-by-wire ECUs. IC Role / Device Role / Timing Role: Nonvolatile configuration store accessed during boot and runtime reconfiguration; 250 ns read latency ensures deterministic response in real-time control loops. Use Value: MIL-STD-883 qualification guarantees operation across -55°C to +125°C thermal cycling, eliminating field failures due to data corruption in high-altitude missions. |
Use Scenario: Holding cryptographic keys and secure boot images in tactical radios operating under EMI-heavy battlefield conditions. IC Role / Device Role / Timing Role: Secure firmware repository with SDP-enabled write lock; hardware VCC sensing prevents key overwrite during power dips. Use Value: Hermetic 28-lead flatpack packaging resists moisture ingress and radiation-induced bit flips, meeting DO-160 Section 22 requirements. |
| Spacecraft Onboard Computer | Nuclear Power Plant Monitoring |
Use Scenario: Retaining telemetry history and fault logs in satellite OBCs exposed to total ionizing dose (TID) >100 krad(Si). IC Role / Device Role / Timing Role: Radiation-tolerant nonvolatile memory for post-event diagnostics; 10-year data retention validated at 125°C ensures long-duration mission integrity. Use Value: Internal error correction and 10,000-cycle endurance support repeated logging over multi-year orbital missions without wear-out risk. |
Use Scenario: Archiving reactor coolant temperature profiles and safety interlock configurations in Class 1E nuclear instrumentation channels. IC Role / Device Role / Timing Role: Safety-critical configuration store with hardware write inhibit preventing unauthorized changes during grid transients. Use Value: Dual-line CE/OE control enables fail-safe bus isolation per IEEE 603, ensuring no spurious writes during electromagnetic interference events. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar paged parallel EEPROM applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| AT28C256-25JM/883 | Same die, 32-lead CERDIP package instead of 28-lead flatpack; larger footprint and different thermal mass | Suitable for legacy CERDIP-based PCBs; less suitable for space-constrained avionics modules requiring flatpack form factor | Select only if existing layout accommodates 32-pin DIP pitch and thermal profile permits higher junction rise |
| DS2502-E48+T&R | 1-Wire serial EEPROM (48-bit EPROM + 128-bit user memory); no parallel interface, no page write, no MIL-STD-883 screening | Used in asset tracking tags and simple sensors; lacks speed, capacity, and environmental robustness for embedded control | Not interchangeable-requires complete interface redesign and fails to meet military temperature or reliability requirements |
Compared with AT28C256-25JM/883, the AT28C256-25FM/883 offers superior board-area efficiency and thermal performance in compact enclosures, while DS2502-E48+T&R cannot replace it in any application demanding parallel access, 256-Kbit density, or MIL-STD-883 compliance.
Availability
AT28C256-25FM/883 is available at Aetrix Electronics and suitable for avionics flight control, military communications, spacecraft onboard computers, and nuclear plant monitoring requiring stable component supply across extended product lifecycles.
Supply support for AT28C256-25FM/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 global semiconductor company specializing in microcontrollers, analog devices, and nonvolatile memory solutions for industrial, automotive, and aerospace markets.
The AT28C256 product line delivers radiation-hardened, temperature-extended parallel EEPROMs designed specifically for mission-critical systems where data integrity, long-term retention, and military-grade reliability are non-negotiable.
FAQ
What is the maximum operating temperature range for the AT28C256-25FM/883?
The AT28C256-25FM/883 is qualified to operate across -55°C to +125°C per MIL-STD-883 Method 1010.2, with full electrical specifications guaranteed over this range. This makes AT28C256-25FM/883 suitable for engine-mounted avionics, missile guidance systems, and other high-temperature military platforms where commercial-grade EEPROMs would fail.
Does the AT28C256-25FM/883 support page write operations, and what is the maximum page size?
Yes, the AT28C256-25FM/883 supports page write operations with a maximum page size of 64 bytes. The device internally latches up to 64 bytes using its page register, allowing sequential writes within 150 µs (tBLC) per byte. This capability is fully implemented in AT28C256-25FM/883 and eliminates the need for external buffering in firmware update routines.
How does hardware write protection function in the AT28C256-25FM/883?
Hardware write protection in the AT28C256-25FM/883 operates through three mechanisms: VCC sensing (write disabled below 3.8 V), a 5 ms power-on delay timer, and noise filtering rejecting pulses <15 ns on WE/CE. These features are silicon-embedded in AT28C256-25FM/883 and require no external components, ensuring immunity to brownouts and EMI-induced writes.
Can the AT28C256-25FM/883 be used as a direct replacement for older AT28C256 variants with different speed grades?
Yes, the AT28C256-25FM/883 maintains full pin, package, and functional compatibility with other AT28C256 speed grades (e.g., -15/-20). Its 250 ns read access time meets or exceeds timing margins of slower variants, and all control logic, page write behavior, and SDP algorithms remain identical-making AT28C256-25FM/883 a seamless upgrade path.
What package type is used for the AT28C256-25FM/883, and is it hermetically sealed?
The AT28C256-25FM/883 uses a 28-lead ceramic flatpack (MIL-STD-1835 F-12 Config B) with glass-sealed ceramic body and gold-plated leads. This package is fully hermetic, certified to MIL-STD-883 Method 1014, and rated for 100% humidity resistance-critical for AT28C256-25FM/883 deployment in maritime, high-altitude, and nuclear environments.
AT28C256-25FM/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
AT28C256-25FM/883 FAQ
1.How can I place an order for AT28C256-25FM/883 through Aetrix?
Please submit a Request for Quotation (RFQ) for AT28C256-25FM/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 AT28C256-25FM/883 reliable?
The price and inventory of AT28C256-25FM/883 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for AT28C256-25FM/883 is usually 5 days.
3.What payment methods are accepted for AT28C256-25FM/883?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for AT28C256-25FM/883 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for AT28C256-25FM/883?
AT28C256-25FM/883 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your AT28C256-25FM/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 AT28C256-25FM/883?
For technical support, including AT28C256-25FM/883 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your AT28C256-25FM/883 requirements.
6.How does Aetrix verify that AT28C256-25FM/883 is sourced from the original manufacturer or authorized distributors?
All AT28C256-25FM/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 AT28C256-25FM/883 meets industry standards.
7.What is the process for return or replacement of AT28C256-25FM/883?
All AT28C256-25FM/883 units undergo pre-shipment inspection (PSI). If there is an issue with AT28C256-25FM/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 AT28C256-25FM/883 part is unused and in its original packaging.
Return procedure for AT28C256-25FM/883:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
AT28C256-25FM/883 Tags
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M24C02-WMN6TP
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AT24C02C-XHM-T
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AT21CS01-STUM10-T
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24LC01BT-I/OT
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M24C02-FMC6TG
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AT24CS02-SSHM-T
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93LC46BT-I/OT
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AT24C04C-SSHM-T
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24LC01BT-I/SN
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