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Microchip Technology AT28C256E-25LM/883-815
- Part No.:
- AT28C256E-25LM/883-815
- Manufacturer:
- Microchip Technology
- Category:
- Memory
- Package:
- 32-CLCC
- Datasheet:
-
AT28C256E-25LM/883-815.pdf
- Description:
- IC EEPROM 256KBIT PARALLEL 32LCC
- Quantity:
- Payment:
- Shipping:
Inventory:3,759
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Product details
Overview
AT28C256E-25LM/883-815 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, and JEDEC-approved byte-wide pinout. It supports page write operations of 1–64 bytes with ≤10 ms write cycle time and delivers 10,000/100,000 endurance cycles for avionics and ruggedized embedded control systems.
For engineers reviewing the AT28C256E-25LM/883-815 datasheet, AT28C256E-25LM/883-815 pinout, AT28C256E-25LM/883-815 application, or AT28C256E-25LM/883-815 equivalent, this device serves as a drop-in replacement for legacy 28C256-based memory subsystems requiring MIL-PRF-38535 Class B qualification, extended temperature operation (−55°C to +125°C), and hardware/software data protection in mission-critical firmware storage.
Technical Context
The AT28C256E-25LM/883-815 implements a static RAM-compatible interface with dual-line chip enable (CE) and output enable (OE) control, enabling bus contention avoidance in multiprocessor systems. Its internal 64-byte page register latches address and data during write initiation, decoupling the host bus for concurrent operations.
Write completion detection uses DATA Polling on I/O7 (complement-to-data toggle) or Toggle Bit behavior on I/O6, both valid across the full military temperature range. Hardware write inhibition includes VCC sense (<3.8 V), 5 ms power-on delay, and noise filtering (<15 ns pulses rejected on CE/WE).
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Memory Density | 256 Kbit (32,768 × 8 words); supports firmware image storage and configuration tables in space-constrained military platforms. |
| Read Access Time | 250 ns max; meets timing requirements for 4 MHz synchronous bus interfaces without wait states. |
| Page Write Cycle Time | ≤10 ms; enables efficient bulk parameter updates in flight control computers without system stall. |
| Endurance | 10,000 or 100,000 write/erase cycles; qualified per MIL-STD-883 Method 1037 for long-life field deployment. |
| Operating Temperature | −55°C to +125°C case temperature; certified to MIL-PRF-38535 Class B for aerospace and defense applications. |
| Supply Voltage | 5.0 V ±10%; compatible with standard TTL/CMOS logic families and eliminates need for auxiliary voltage regulators. |
| Standby Current | 300 µA CMOS; reduces quiescent power in always-on avionics modules during sleep modes. |
Pinout & Package
AT28C256E-25LM/883-815 is supplied in a 32-pad Ceramic Leadless Chip Carrier (CLCC) package compliant with MIL-STD-1835 C-12, featuring hermetic ceramic construction and gold-plated terminations for high-reliability interconnects.
| 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 | 8-bit parallel data path; I/O7 provides DATA Polling status; I/O6 provides Toggle Bit status during write cycles. |
| CE | Chip Enable | Active-low chip 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 pins in high-impedance state when high, preventing bus contention. |
| WE | Write Enable | Active-low write strobe; controls byte/page write initiation and timing; rejects sub-15 ns noise pulses. |
| VCC | Power Supply | +5 V ±10% main supply; powers core logic and I/O buffers; includes internal VCC sense circuitry for write inhibit below 3.8 V. |
| GND | Ground Reference | Signal and power return; requires low-inductance connection to minimize ground bounce during page write current surges. |
| DC (Pins 1 & 17) | Don't Connect | No internal connection; must remain unconnected per MIL-STD-1835 C-12 mechanical specification. |
Key Features
| Feature | Design Value |
|---|---|
| JEDEC Byte-Wide Pinout | Direct compatibility with legacy 27C256/28C256 socket designs-no PCB redesign required for upgrade paths. |
| Software Data Protection (SDP) | Three-byte unlock sequence (AAh/55h/A0h) enables/disables write protection; prevents inadvertent reprogramming during power transitions. |
| Internal Page Register | 64-byte latch allows burst loading of up to 64 bytes before internal programming begins-maximizes host CPU utilization. |
| Hardware Write Inhibit | VCC sense, 5 ms power-on delay, and noise filtering eliminate false writes during brown-out or EMI events in harsh environments. |
| Device Identification Area | 64-byte reserved sector (7FC0h–7FFFh) accessible at 12 V on A9 for unique unit serialization and traceability. |
Applications
| Avionics Flight Control | Military Radio Firmware Storage |
|---|---|
|
Use Scenario: Storing real-time flight control algorithms and sensor calibration tables in fly-by-wire systems operating at −55°C to +125°C. IC Role / Device Role / Timing Role: Nonvolatile program memory providing deterministic 250 ns read access and page-write capability for in-field software updates. Use Value: Eliminates external wait-state generators and supports MIL-STD-1553B bus timing constraints via JEDEC-compliant pinout. |
Use Scenario: Holding encrypted radio waveform definitions and cryptographic keys in handheld tactical radios subjected to shock/vibration. IC Role / Device Role / Timing Role: Secure configuration storage with hardware/software write protection ensuring integrity during battery swaps and thermal cycling. Use Value: 100,000-cycle endurance and hermetic CLCC packaging guarantee >15-year data retention in deployed units. |
| Spacecraft Onboard Computer | Tactical Vehicle Engine Control |
|
Use Scenario: Retaining boot firmware and fault-tolerant diagnostic routines in radiation-hardened satellite subsystems. IC Role / Device Role / Timing Role: Radiation-tolerant nonvolatile memory with DATA Polling support for autonomous write verification without host intervention. Use Value: Single 5 V supply simplifies power architecture; 300 µA standby current extends battery life during orbital eclipse periods. |
Use Scenario: Storing engine calibration maps and emission control parameters in armored vehicle ECUs exposed to diesel particulate and wide thermal swings. IC Role / Device Role / Timing Role: High-reliability firmware repository supporting over-the-air updates via CAN bus with verified write completion. Use Value: Toggle Bit and DATA Polling provide dual, independent write-status channels-critical for safety-critical ISO 26262 ASIL-B compliance. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar paged parallel EEPROM applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| AT28C256-25JU | Commercial-grade 32-pin PLCC; no MIL-PRF-38535 qualification; 0°C to +70°C temp range. | Lacks radiation tolerance, hermetic sealing, and extended temperature performance required for aerospace use. | Select only for cost-sensitive ground-test equipment where military specs are not mandated. |
| MX28F256K | Intel-compatible 256 Kbit flash; 12 V programming; no built-in page register or DATA Polling. | Requires external erase/program controllers; incompatible pinout and timing; no Toggle Bit support. | Use only when migrating legacy Intel 28F256 designs-requires full board redesign and firmware adaptation. |
Compared with AT28C256E-25LM/883-815, AT28C256-25JU sacrifices environmental robustness for lower cost, while MX28F256K replaces EEPROM architecture with flash, eliminating true byte-write capability and increasing system complexity for write-status monitoring.
Availability
AT28C256E-25LM/883-815 is available at Aetrix Electronics and suitable for avionics flight control, military radio firmware storage, spacecraft onboard computers, and tactical vehicle engine control requiring stable component supply under MIL-PRF-38535 Class B sourcing.
Supply support for AT28C256E-25LM/883-815 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-tolerant, high-endurance EEPROMs designed specifically for mission-critical firmware and configuration storage in MIL-STD-810G and DO-160-compliant systems.
FAQ
What is the maximum page write size supported by the AT28C256E-25LM/883-815?
The AT28C256E-25LM/883-815 supports page write operations of 1 to 64 bytes per internal programming cycle. All bytes must reside within the same 64-byte page defined by address bits A6–A14, and successive bytes must be loaded within 150 µs (tBLC) to avoid premature write initiation. This capability is implemented in the AT28C256E-25LM/883-815's internal 64-byte page register and enables efficient firmware patching without full-chip erase.
Does the AT28C256E-25LM/883-815 require a 12 V supply for any operation?
The AT28C256E-25LM/883-815 operates exclusively from a single 5 V ±10% supply for all standard read/write functions. A 12 V ±0.5 V supply on pin A9 is required only for accessing the 64-byte device identification area (7FC0h–7FFFh); it is not needed for normal memory operation, page writes, or software data protection sequences. This 12 V requirement is strictly limited to the ID sector and does not affect AT28C256E-25LM/883-815's primary functionality.
How is write completion detected on the AT28C256E-25LM/883-815?
Write completion on the AT28C256E-25LM/883-815 is detected using two independent hardware methods: DATA Polling on I/O7 (which returns complement-of-data until write completes) and Toggle Bit behavior on I/O6 (which toggles between 0 and 1 during active programming). Both mechanisms are fully functional across the −55°C to +125°C military temperature range and require no additional timing margins beyond the specified tWC maximum of 10 ms. These features are integral to the AT28C256E-25LM/883-815's architecture and do not rely on external controllers.
What package type is used for the AT28C256E-25LM/883-815?
The AT28C256E-25LM/883-815 is packaged in a 32-pad Ceramic Leadless Chip Carrier (CLCC) conforming to MIL-STD-1835 C-12. This hermetically sealed ceramic package features gold-plated terminations, zero insertion force compatibility, and mechanical robustness for high-vibration environments. Pins 1 and 17 are designated "Don't Connect" and must remain unconnected-this is a mandatory requirement specified in the AT28C256E-25LM/883-815's official packaging documentation.
Is software data protection enabled by default on the AT28C256E-25LM/883-815?
No, software data protection (SDP) is disabled by default on the AT28C256E-25LM/883-815. The device ships with SDP inactive, allowing immediate byte or page writes upon power-up. SDP must be explicitly enabled using the three-byte unlock sequence (AAh to 5555h, 55h to 2AAAh, A0h to 5555h). Once enabled, SDP remains active through power cycles and requires the separate disable sequence (AAh/55h/80h/AAh/20h/55h/2AAAh) to deactivate. This behavior is guaranteed for every AT28C256E-25LM/883-815 unit.
AT28C256E-25LM/883-815 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Microchip Technology
- Series:
- -
- Package/Case:
- 32-CLCC
- 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:
- 32-LCC (11.43x13.97)
AT28C256E-25LM/883-815 FAQ
1.How can I place an order for AT28C256E-25LM/883-815 through Aetrix?
Please submit a Request for Quotation (RFQ) for AT28C256E-25LM/883-815 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 AT28C256E-25LM/883-815 reliable?
The price and inventory of AT28C256E-25LM/883-815 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for AT28C256E-25LM/883-815 is usually 5 days.
3.What payment methods are accepted for AT28C256E-25LM/883-815?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for AT28C256E-25LM/883-815 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for AT28C256E-25LM/883-815?
AT28C256E-25LM/883-815 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your AT28C256E-25LM/883-815 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 AT28C256E-25LM/883-815?
For technical support, including AT28C256E-25LM/883-815 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your AT28C256E-25LM/883-815 requirements.
6.How does Aetrix verify that AT28C256E-25LM/883-815 is sourced from the original manufacturer or authorized distributors?
All AT28C256E-25LM/883-815 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 AT28C256E-25LM/883-815 meets industry standards.
7.What is the process for return or replacement of AT28C256E-25LM/883-815?
All AT28C256E-25LM/883-815 units undergo pre-shipment inspection (PSI). If there is an issue with AT28C256E-25LM/883-815, 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 AT28C256E-25LM/883-815 part is unused and in its original packaging.
Return procedure for AT28C256E-25LM/883-815:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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