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Microchip Technology AT28C256-15FM/883
- Part No.:
- AT28C256-15FM/883
- Manufacturer:
- Microchip Technology
- Category:
- Memory
- Package:
- 28-CFlatPack
- Datasheet:
-
AT28C256-15FM/883.pdf
- Description:
- IC EEPROM 256KBIT PAR 28FLATPK
- Quantity:
- Payment:
- Shipping:
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Product details
Overview
AT28C256-15FM/883 from Microchip Technology is a military-grade paged parallel EEPROM with 256-Kbit (32,768 × 8) organization, 150 ns read access time, single 5V ±10% supply operation, and JEDEC-approved byte-wide pinout. It supports page write cycles of up to 64 bytes with 3 ms maximum duration and delivers 10,000–100,000 write endurance cycles for embedded avionics and defense system firmware storage.
For engineers reviewing the AT28C256-15FM/883 datasheet, AT28C256-15FM/883 pinout, AT28C256-15FM/883 application, or AT28C256-15FM/883 equivalent, this page provides verified military-spec timing, hardware/software data protection implementation details, page write timing constraints, DC/AC operating ranges, and MIL-STD-883 qualified package markings - all critical for DO-254, MIL-HDBK-217F, and radiation-tolerant design validation.
Technical Context
The AT28C256-15FM/883 implements a CMOS-based paged architecture with internal 64-byte latches and autonomous control timer, enabling simultaneous multi-byte writes without external address/data bus hold. Its dual-line chip enable (CE) and output enable (OE) logic allows precise bus contention control in multiprocessor memory maps.
It integrates VCC sense circuitry (write inhibit below 3.8 V), 5 ms power-on delay, noise filtering on WE/CE inputs (<15 ns rejection), and optional software data protection using three-step command sequences at addresses 5555H/2AAAH. Device identification space (7FC0H–7FFFH) is accessible via A9 = 12 V ±0.5 V.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Memory Density | 256 Kbit (32,768 × 8) - supports full 16-bit address space with byte-level random access |
| Read Access Time | 150 ns max - enables direct replacement for SRAM in legacy MIL-STD-1553B or 80C86-based systems |
| Page Write Cycle Time | 3 ms max - reduces firmware update latency vs. byte-write-only EEPROMs by 98% per 64-byte block |
| Endurance | 10,000 or 100,000 cycles - selectable via part marking; ensures field-programmable mission-critical configuration storage |
| Data Retention | 10 years minimum at +125°C - validated under MIL-PRF-38535 Class B screening for long-life airborne platforms |
| Supply Voltage | 5 V ±10% - compatible with legacy TTL/CMOS logic rails without level-shifting circuitry |
| Operating Temperature | −55°C to +125°C - meets MIL-STD-883 Method 1010.8 temperature cycling requirements |
Pinout & Package
AT28C256-15FM/883 is supplied in a 32-lead flatpack (MIL-STD-1835 F-12 Config B), hermetically sealed ceramic package with 0.600" width, 28-pin footprint, and military-grade marking per 5962-88525 specification. Pin 1 identified by notch; pins 1–14 and 15–28 arranged linearly on opposing sides.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| A0–A14 | Address Inputs | 15-bit address bus supporting full 32K-word addressing; A6–A14 define page boundaries for 64-byte writes |
| I/O0–I/O7 | Bidirectional Data Bus | CMOS/TTL-compatible 8-bit data path; I/O7 used for DATA Polling, I/O6 for Toggle Bit end-of-write detection |
| CE | Chip Enable | Active-low chip select; must be low with OE low and WE high for read; initiates write when pulsed low with OE high |
| OE | Output Enable | Active-low output gate; controls bus drive; high during write cycles to prevent contention |
| WE | Write Enable | Active-low write strobe; falling edge latches address/data; high-to-low transitions trigger byte or page programming |
| VCC | Power Supply | +5 V ±10% main supply; internal VCC sense disables writes below 3.8 V typical |
| GND | Ground Reference | Signal and power return; decoupling required within 10 mm of VCC pin per MIL-STD-1537 |
| NC / DC | No Connect / Don't Connect | Pins marked NC or DC (e.g., pins 12, 26 in CLCC; pins 1, 17 in 32-pad CLCC) must remain unconnected per datasheet |
Key Features
| Feature | Design Value |
|---|---|
| Hardware Data Protection | VCC sense + 5 ms power-on delay + noise-filtered WE/CE inputs prevent spurious writes during brown-out or EMI events |
| Software Data Protection (SDP) | Three-step command sequence (AAH→55H→A0H) enables/disables write lock; survives power cycling and retains state |
| DATA Polling & Toggle Bit | I/O7 complement output and I/O6 toggling provide real-time, bus-compatible write completion signaling without polling overhead |
| Page Write Architecture | Internal 64-byte latch frees address/data bus after initial byte load, enabling concurrent host CPU operations during 3 ms internal programming |
| MIL-STD-883 Qualified | Screened to Method 1010.8 (temperature cycling), 2010.9 (steady-state life), and 2036.1 (hermeticity); marked "/883" and "5962-88525" |
Applications
| Avionics Configuration Storage | Secure Bootloader Firmware |
|---|---|
Use Scenario: Storing flight control parameter sets, sensor calibration tables, and navigation database checksums in MIL-STD-1553B-equipped UAVs. IC Role / Device Role / Timing Role: Nonvolatile configuration register bank accessed via parallel bus during power-up initialization and in-flight reconfiguration. Use Value: 150 ns read access enables deterministic boot timing; 10-year data retention ensures integrity across 20,000+ flight hours without refresh. | Use Scenario: Holding signed bootloader images and cryptographic keys in encrypted secure boot chains for airborne mission computers. IC Role / Device Role / Timing Role: Trusted firmware repository with hardware-enforced write protection during runtime and SDP-enabled lockdown post-verification. Use Value: VCC-sense and software lock prevent unauthorized firmware modification during voltage transients or debug interface exposure. |
| Radiation-Tolerant Telemetry Logging | Legacy Weapon System Memory Upgrade |
Use Scenario: Capturing pre-launch diagnostics and in-mission telemetry snapshots in space-qualified launch vehicle control modules. IC Role / Device Role / Timing Role: High-reliability logging buffer interfaced to 80C86 or Z80 derivatives via ISA-style parallel bus. Use Value: 100,000-cycle endurance and −55°C to +125°C operation support repeated mission-critical data capture over 15+ years. | Use Scenario: Replacing obsolete 27C256 EPROMs in radar signal processors requiring field-upgradable firmware without UV erasure. IC Role / Device Role / Timing Role: Drop-in parallel memory replacement with identical JEDEC pinout and 5 V compatibility. Use Value: Eliminates UV eraser dependency and enables in-system firmware updates via existing board-level programming interfaces. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar paged parallel EEPROM applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| AT28C256-15JM/883 | Same die, 32-lead CERDIP package instead of flatpack; identical AC/DC specs and MIL-STD-883 screening | Preferred where board layout uses through-hole CERDIP footprints or requires different thermal mass profile | Select based on mechanical fit and solder joint reliability requirements per MIL-STD-202G Method 210 |
| DS2502-E48+ | 1-Wire serial EEPROM (48-bit ID + 1024-bit user memory); no parallel interface; lower density; no MIL-STD-883 qualification | Suitable only for low-bandwidth, single-wire diagnostic ID storage-not for firmware or configuration replacement | Not a functional substitute; use only for supplemental device identification, not primary memory function |
Compared with AT28C256-15FM/883, the AT28C256-15JM/883 offers identical electrical performance and military qualification in a different hermetic package, while DS2502-E48+ lacks parallel interface, endurance, and temperature range - making it unsuitable for firmware storage or real-time configuration roles.
Availability
AT28C256-15FM/883 is available at Aetrix Electronics and suitable for avionics configuration storage, secure bootloader firmware, radiation-tolerant telemetry logging, and legacy weapon system memory upgrades requiring stable component supply across extended production lifecycles.
Supply support for AT28C256-15FM/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 AT28C256 product line was designed for high-reliability, radiation-tolerant, and extended-temperature embedded systems requiring field-upgradable nonvolatile memory with deterministic timing and hardware-enforced data integrity.
FAQ
What is the maximum page write size supported by the AT28C256-15FM/883?
The AT28C256-15FM/883 supports up to 64 bytes per page write operation. All bytes must reside on the same page defined by address bits A6–A14, and successive bytes must be loaded within 150 µs (tBLC) of each other. The internal page latch holds the data, freeing the address and data bus for other operations during the 3 ms internal programming cycle. This capability is confirmed in Section 6.8 and Figure 6-9 of the DS20006344A datasheet.
Does the AT28C256-15FM/883 require external high-voltage programming signals?
No, the AT28C256-15FM/883 operates from a single 5 V ±10% supply and does not require external high-voltage programming signals for standard byte or page writes. Only the optional Chip Erase mode (Section 6.10) and Device Identification memory (Section 6) require 12 V ±0.5 V applied to A9. All normal read/write operations use standard TTL/CMOS logic levels, simplifying integration into legacy 5 V systems.
How is hardware write protection implemented in the AT28C256-15FM/883?
Hardware write protection in the AT28C256-15FM/883 uses four mechanisms: (1) VCC sense circuitry inhibits writes if supply drops below 3.8 V typical; (2) automatic 5 ms power-on delay before write enable; (3) write inhibition when OE is low, CE is high, or WE is high; and (4) noise filtering rejecting pulses <15 ns on WE/CE inputs. These features are detailed in Section 6 of DS20006344A and ensure immunity to power glitches and EMI-induced corruption.
What MIL-STD-883 test methods apply to the AT28C256-15FM/883?
The AT28C256-15FM/883 is screened per MIL-STD-883 Method 1010.8 (temperature cycling), 2010.9 (steady-state life), and 2036.1 (fine-leak hermeticity). Its marking "/883" and "5962-88525" confirm compliance with Defense Logistics Agency (DLA) requirements for Class B hybrid microcircuits. Full qualification data is documented in Microchip's QML-38535 listing and DLA Land and Maritime QML certification reports.
Can the AT28C256-15FM/883 be used as a direct replacement for the AT28C256-15JM/883?
Yes, the AT28C256-15FM/883 and AT28C256-15JM/883 share identical electrical specifications, timing parameters, pin functions, and MIL-STD-883 qualification - differing only in package type (flatpack vs. CERDIP). Both use the same JEDEC byte-wide pinout and support identical software data protection, page write, and polling protocols. Mechanical fit and thermal profile should be verified per board-level drawings.
AT28C256-15FM/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:
- 150 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
AT28C256-15FM/883 FAQ
1.How can I place an order for AT28C256-15FM/883 through Aetrix?
Please submit a Request for Quotation (RFQ) for AT28C256-15FM/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 AT28C256-15FM/883 reliable?
The price and inventory of AT28C256-15FM/883 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for AT28C256-15FM/883 is usually 5 days.
3.What payment methods are accepted for AT28C256-15FM/883?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for AT28C256-15FM/883 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for AT28C256-15FM/883?
AT28C256-15FM/883 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your AT28C256-15FM/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 AT28C256-15FM/883?
For technical support, including AT28C256-15FM/883 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your AT28C256-15FM/883 requirements.
6.How does Aetrix verify that AT28C256-15FM/883 is sourced from the original manufacturer or authorized distributors?
All AT28C256-15FM/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 AT28C256-15FM/883 meets industry standards.
7.What is the process for return or replacement of AT28C256-15FM/883?
All AT28C256-15FM/883 units undergo pre-shipment inspection (PSI). If there is an issue with AT28C256-15FM/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 AT28C256-15FM/883 part is unused and in its original packaging.
Return procedure for AT28C256-15FM/883:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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