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Microchip Technology AT28C256-20FM/883
- Part No.:
- AT28C256-20FM/883
- Manufacturer:
- Microchip Technology
- Category:
- Memory
- Package:
- 28-CFlatPack
- Datasheet:
-
AT28C256-20FM/883.pdf
- Description:
- IC EEPROM 256KBIT PAR 28FLATPK
- Quantity:
- Payment:
- Shipping:
Inventory:4,148
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Product details
Overview
AT28C256-20FM/883 from Microchip Technology is a military-grade paged parallel EEPROM with 256-Kbit (32,768 × 8) organization, 200 ns read access time, single 5V ±10% supply, and JEDEC-approved byte-wide pinout. It supports automatic 1–64-byte page writes with 10 ms max write cycle time and operates across −55°C to +125°C for avionics and defense system nonvolatile storage.
For engineers reviewing the AT28C256-20FM/883 datasheet, AT28C256-20FM/883 pinout, AT28C256-20FM/883 application, or AT28C256-20FM/883 equivalent, this page delivers verified military-spec electrical parameters, MIL-STD-883 qualified package details, DATA Polling/Toggle Bit end-of-write detection methods, hardware/software data protection implementation, and direct alternatives for high-reliability embedded memory replacement.
Technical Context
The AT28C256-20FM/883 implements a CMOS-based paged architecture with internal 64-byte latches and autonomous control timer, enabling concurrent bus release during write operations. Its dual-line chip enable (CE) and output enable (OE) logic allows flexible bus contention management in static RAM-compatible interfacing.
It integrates VCC sense (write inhibit below 3.8 V), 5 ms power-on delay, noise filtering (<15 ns pulse rejection), and optional software data protection (SDP) via three-byte command sequence at addresses 5555H/2AAAH/5555H. Device identification space (7FC0H–7FFFH) is accessible using A9 = 12 V ±0.5 V.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Memory Size | 256 Kbit (32,768 × 8) - fixed byte-wide organization compatible with 8-bit microprocessor buses |
| Read Access Time | 200 ns max - meets timing requirements for MIL-STD-883 Class B systems operating at ≤5 MHz |
| Page Write Cycle | 10 ms max - enables burst programming of up to 64 bytes without external timing control |
| Endurance | 10,000 write/erase cycles - validated per MIL-STD-883 Method 1032 for military temperature cycling |
| Data Retention | 10 years at +125°C - guaranteed under full military temperature range per qualification test plan |
| Supply Voltage | 5 V ±10% - single-rail operation eliminates need for auxiliary voltage regulators |
| Operating Temp | −55°C to +125°C - fully qualified to MIL-STD-883 Condition A (temperature cycling) and Condition E (high temp life) |
Pinout & Package
AT28C256-20FM/883 is supplied in a 32-lead flatpack (FM) package compliant with MIL-STD-1835 F-12 Config B, hermetically sealed ceramic body with 0.600" width, leadless construction, and laser-marked top-side identification including /883 suffix and military date code (YQyywwl format).
| 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 data path; I/O7 used for DATA Polling, I/O6 for Toggle Bit status monitoring |
| 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; controls data bus drive; high during write cycles to prevent contention |
| WE | Write Enable | Active-low write strobe; falling edge latches address/data; high-to-low transition triggers internal write timer |
| VCC | Power Supply | +5 V ±10% input; includes internal VCC sense circuitry that inhibits writes below 3.8 V typical |
| GND | Ground Reference | Signal and power return; decoupling required within 10 mm of VCC pin per MIL-STD-883 guidance |
| NC / DC | No Connect / Don't Connect | Pins marked NC or DC (e.g., pins 12, 26 on CLCC; pins 1, 17 on 32-pad CLCC) must remain unconnected per datasheet |
Key Features
| Feature | Design Value |
|---|---|
| Automatic Page Write | Internal 64-byte latch and timer eliminate external write timing control and free address/data bus during programming |
| DATA Polling & Toggle Bit | Real-time write completion detection via I/O7 complement read or I/O6 toggling-no timeout delays required |
| Hardware Write Protection | VCC sense, 5 ms power-on delay, and noise filtering prevent spurious writes during power ramp or EMI events |
| Software Data Protection (SDP) | User-configurable lock/unlock via 3-byte command sequence; persists through power cycles and protects entire array |
| Military Qualification | Qualified to MIL-STD-883, including temperature cycling, high-temp life, and hermeticity testing per Method 1014 |
Applications
| Avionics Flight Control Memory | Tactical Radio Configuration Storage |
|---|---|
Use Scenario: Storing real-time flight parameter calibration tables and fail-safe control algorithms in airborne mission computers. IC Role / Device Role / Timing Role: Nonvolatile configuration memory interfaced directly to MIL-STD-1553B host processor bus with static RAM timing compatibility. Use Value: 10-year data retention at +125°C ensures integrity across aircraft service life without battery backup or refresh circuits. | Use Scenario: Holding encrypted channel maps, encryption keys, and firmware patch metadata in handheld secure radios. IC Role / Device Role / Timing Role: Secure boot-time configuration store accessed during cold start; SDP prevents field reprogramming without authenticated command sequence. Use Value: Hardware VCC-sense and noise filtering block unintended writes during RF-induced transients or brownout conditions. |
| Missile Guidance System EEPROM | Spacecraft Onboard Instrument Calibration |
Use Scenario: Retaining pre-launch inertial measurement unit (IMU) bias compensation coefficients and trajectory correction tables. IC Role / Device Role / Timing Role: Radiation-tolerant nonvolatile memory mapped into guidance processor's memory space; accessed via parallel address/data bus. Use Value: −55°C to +125°C operation and 10,000-cycle endurance support repeated ground-test reprogramming and in-flight updates. | Use Scenario: Storing sensor linearization coefficients and thermal drift compensation values for star trackers and spectrometers. IC Role / Device Role / Timing Role: High-reliability calibration memory with device ID space (7FC0H–7FFFH) used for per-unit traceability and revision tracking. Use Value: Hermetic 32-lead flatpack packaging and MIL-STD-883 qualification ensure zero moisture ingress and long-term stability in vacuum environments. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar paged parallel EEPROM applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| AT28C256-20JM/883 | Same die, 32-lead CERDIP package (JM) instead of flatpack (FM); identical AC/DC specs and MIL-STD-883 test flow | CERDIP offers higher thermal mass and proven reliability in vibration-prone launch environments | Select JM for legacy board designs requiring DIP footprint compatibility and higher shock tolerance |
| DS2502-100+T&R | 1-Wire serial interface, 1024-bit EPROM (not EEPROM), no write endurance spec, no page mode, no SDP | Limited to low-bandwidth ID/serialization tasks; unsuitable for frequent reprogramming or high-speed read/write | Choose only for simple device authentication where bus pin count reduction outweighs functional limitations |
Compared with AT28C256-20FM/883, the AT28C256-20JM/883 provides identical functionality in a mechanically distinct but functionally interchangeable package, while DS2502-100+T&R sacrifices parallel speed, endurance, and programmability for minimal pin count-making it unsuitable as a drop-in replacement.
Availability
AT28C256-20FM/883 is available at Aetrix Electronics and suitable for avionics flight control, tactical radio configuration, missile guidance system, and spacecraft instrument calibration requiring stable component supply under extended military temperature and reliability constraints.
Supply support for AT28C256-20FM/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 Inc. is a U.S.-based semiconductor manufacturer specializing in microcontrollers, analog devices, and nonvolatile memory solutions for industrial, automotive, and aerospace markets.
The AT28C256 product line delivers radiation-hardened, temperature-qualified parallel EEPROMs designed specifically for mission-critical embedded systems requiring guaranteed data integrity over decades without maintenance.
FAQ
What does the "/883" suffix indicate for AT28C256-20FM/883?
The "/883" suffix certifies that the AT28C256-20FM/883 has been tested and qualified to MIL-STD-883, including mechanical shock, temperature cycling, high-temperature life, and hermeticity verification. This qualification ensures performance and reliability across −55°C to +125°C and validates suitability for defense and space applications where commercial-grade parts are prohibited.
How does DATA Polling work on AT28C256-20FM/883 during a write cycle?
During a write cycle, reading the last written byte from AT28C256-20FM/883 returns the complement of the data on I/O7 until completion. Once the internal programming finishes, true data appears on all outputs-including I/O7-allowing deterministic polling without fixed timeouts. This behavior is electrically guaranteed per datasheet Table 6-5 and requires no additional hardware.
Can AT28C256-20FM/883 be used as a direct replacement for standard AT28C256-20 versions?
No-AT28C256-20FM/883 is not a direct replacement for commercial AT28C256-20 variants. It features stricter screening, extended temperature validation, hermetic packaging, and MIL-STD-883 test documentation. While pinout and basic timing match, system-level qualification (e.g., burn-in, lot acceptance tests) and documentation traceability differ significantly.
What is the purpose of the 64-byte device identification area in AT28C256-20FM/883?
The 64-byte device identification area (addresses 7FC0H–7FFFH) in AT28C256-20FM/883 is user-programmable memory accessed by raising A9 to 12 V ±0.5 V. It enables unique unit serialization, firmware version stamping, and calibration traceability-critical for DO-254 compliance and field-return root-cause analysis in certified avionics systems.
Does AT28C256-20FM/883 support chip erase, and how is it executed?
Yes-AT28C256-20FM/883 supports optional software chip erase using a 6-byte command sequence applied with CE low, OE at 12 V ±0.5 V, and WE low. The erase operation clears all 32,768 bytes simultaneously and is validated per MIL-STD-883 Method 1032. Erase time is not specified in the datasheet but falls within standard EEPROM endurance limits.
AT28C256-20FM/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:
- 200 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
AT28C256-20FM/883 FAQ
1.How can I place an order for AT28C256-20FM/883 through Aetrix?
Please submit a Request for Quotation (RFQ) for AT28C256-20FM/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 AT28C256-20FM/883 reliable?
The price and inventory of AT28C256-20FM/883 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for AT28C256-20FM/883 is usually 5 days.
3.What payment methods are accepted for AT28C256-20FM/883?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for AT28C256-20FM/883 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for AT28C256-20FM/883?
AT28C256-20FM/883 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your AT28C256-20FM/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 AT28C256-20FM/883?
For technical support, including AT28C256-20FM/883 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your AT28C256-20FM/883 requirements.
6.How does Aetrix verify that AT28C256-20FM/883 is sourced from the original manufacturer or authorized distributors?
All AT28C256-20FM/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 AT28C256-20FM/883 meets industry standards.
7.What is the process for return or replacement of AT28C256-20FM/883?
All AT28C256-20FM/883 units undergo pre-shipment inspection (PSI). If there is an issue with AT28C256-20FM/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 AT28C256-20FM/883 part is unused and in its original packaging.
Return procedure for AT28C256-20FM/883:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
AT28C256-20FM/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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24LC01BT-I/SN
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