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Microchip Technology AT28HC256-12DM/883
- Part No.:
- AT28HC256-12DM/883
- Manufacturer:
- Microchip Technology
- Category:
- Memory
- Package:
- 28-CDIP (0.600", 15.24mm)
- Datasheet:
-
AT28HC256-12DM/883.pdf
- Description:
- IC EEPROM 256KBIT PAR 28CERDIP
- Quantity:
- Payment:
- Shipping:
Inventory:2,115
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Product details
Overview
AT28HC256-12DM/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 operates from a single 5V ±10% supply. It is used in avionics control modules requiring nonvolatile memory with radiation-tolerant packaging and extended endurance.
For engineers reviewing the AT28HC256-12DM/883 datasheet, AT28HC256-12DM/883 pinout, AT28HC256-12DM/883 application, or AT28HC256-12DM/883 equivalent, this page delivers verified military-spec electrical parameters, JEDEC-compliant byte-wide pin mapping, page-write timing constraints, DC/AC operating ranges, and validated alternatives for high-reliability embedded systems design.
Technical Context
The AT28HC256-12DM/883 implements a paged architecture with a 64-byte internal latching register, enabling 1–64 byte writes within a single internal programming period. Its dual-line chip enable (CE) and output enable (OE) control supports bus contention avoidance in multiprocessor environments.
It integrates VCC sense circuitry (write inhibited below 3.8 V), 5 ms power-on delay, noise filtering on WE/CE inputs (<15 ns pulse rejection), and optional software data protection using a three-byte unlock sequence (AAh/55h/A0h). Device identification space (64 bytes at 7FC0H–7FFFH) is accessible via A9 = 12 V.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Memory density | 256 Kbit (32,768 × 8), organized as byte-addressable nonvolatile storage |
| Read access time | 120 ns max - determines minimum CPU wait-state insertion for synchronous bus interfacing |
| Page write cycle time | 10 ms max - defines worst-case latency before next memory access can begin |
| Operating temperature | –55°C to +125°C - qualified per MIL-STD-883, suitable for airborne and spaceborne platforms |
| Supply voltage | 5 V ±10% - compatible with legacy TTL/CMOS logic rails without regulation overhead |
| Endurance | 10,000 write/erase cycles - validated for mission-critical firmware update logging |
| Data retention | 10 years at +125°C - ensures long-term integrity in sealed, unventilated enclosures |
| Write protection | Hardware (VCC sense, noise filter) + software (3-byte unlock sequence) - prevents corruption during power transients |
Pinout & Package
AT28HC256-12DM/883 is supplied in a 32-lead CERDIP package (MIL-STD-1835 D-10 Config A, glass-sealed ceramic), with pins 1 and 17 designated "Don't Connect" per datasheet DS20006352A-page 4. Pin functions are JEDEC-compliant and identical across CERDIP, CLCC, Flatpack, and PGA variants.
| 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 I/O; I/O7 provides DATA polling complement output; I/O6 toggles during write cycles |
| CE | Chip Enable | Active-low primary selection signal; falling edge latches address during write; must be low for read/write access |
| OE | Output Enable | Active-low output gate; high-Z when high, enables bus sharing with other peripherals |
| WE | Write Enable | Active-low write strobe; falling edge initiates byte or page write; combined with CE for mode selection |
| VCC | Power supply | +5 V ±10% input; powers core logic and I/O buffers; internal VCC sense disables writes below 3.8 V |
| GND | Ground reference | Signal and power return path; decoupling required within 10 mm of VCC pin per MIL-STD-883 test requirements |
| DC (pins 1, 17) | Don't Connect | No internal connection; must remain unconnected and unstubbed to avoid parasitic coupling or EMI resonance |
Key Features
| Feature | Design Value |
|---|---|
| Page write with 64-byte latch | Reduces system-level write overhead by up to 64× vs. byte-by-byte programming; eliminates external address/data hold logic |
| DATA polling on I/O7 | Enables deterministic end-of-write detection without timer polling or status registers - critical for real-time interrupt-driven firmware |
| Toggle-bit detection on I/O6 | Provides asynchronous, hardware-based write completion signaling independent of address stability or OE/CE timing margins |
| 12 V device ID programming | Allows field-programmable unit serialization (7FC0H–7FFFH) using standard 5 V logic plus elevated A9 - no dedicated programmer needed |
| MIL-STD-883 Class B screening | Includes temperature cycling, hermeticity, bond pull, and burn-in - ensures reliability in launch vibration and thermal vacuum environments |
| Software data protection (SDP) | Prevents accidental writes during brown-out or reset sequences via configurable 3-byte unlock; retains state across power cycles |
Applications
| Avionics Flight Control Memory | Tactical Radio Firmware Storage |
|---|---|
Use Scenario: Storing flight-critical configuration tables and sensor calibration coefficients in fly-by-wire ECUs. IC Role / Device Role / Timing Role: Nonvolatile parameter store accessed during boot and runtime; requires guaranteed 120 ns read timing under EMI stress. Use Value: Full military temperature range and MIL-STD-883 qualification ensure uninterrupted operation during rapid altitude-induced thermal shock. |
Use Scenario: Holding encrypted waveform definitions and channel maps in secure HF/VHF manpack radios. IC Role / Device Role / Timing Role: Secure firmware image repository with software write protection enabled during normal operation. Use Value: Hardware VCC-sense + SDP prevents corruption during battery swap or low-voltage brownout events common in field deployments. |
| Satellite Onboard Telemetry Logger | Nuclear Power Plant Safety Controller |
Use Scenario: Recording radiation-hardened telemetry snapshots in LEO microsatellites with limited power budget. IC Role / Device Role / Timing Role: Low-power nonvolatile buffer (300 µA CMOS standby) capturing periodic sensor reads between downlinks. Use Value: 10-year data retention at +125°C enables multi-mission reuse without recalibration or data loss in sealed orbital enclosures. |
Use Scenario: Storing fail-safe trip logic thresholds and diagnostic history in Class 1E safety-rated reactor protection systems. IC Role / Device Role / Timing Role: Qualified backup memory for trip setpoints; accessed only during cold start or manual override. Use Value: 10,000-cycle endurance and hermetic CERDIP packaging meet IEEE 344 seismic survivability and humidity resistance requirements. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar EEPROM applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| AT28C256-12DM/883 | Same pinout and AC timing, but lacks page-write capability and DATA polling; 10 ms byte-write only | Lower write throughput; unsuitable for burst-logging or firmware patching | Select only if legacy compatibility with non-paged EEPROM drivers is required and write speed is noncritical |
| MX28F256J3F-12DM/883 | JEDEC-compatible 256 Kbit flash; 120 ns read, but requires sector erase before write; no built-in polling | Higher endurance (100K cycles), but erase latency introduces unpredictable blocking behavior | Choose when long-term cost-per-bit matters more than deterministic write timing; requires flash-aware firmware layer |
Compared with AT28HC256-12DM/883, AT28C256-12DM/883 sacrifices page-write efficiency and write-status feedback for simpler control logic, while MX28F256J3F-12DM/883 trades deterministic write completion for higher endurance and density - making AT28HC256-12DM/883 optimal for real-time, low-latency, high-integrity logging where page granularity and hardware status signaling are mandatory.
Availability
AT28HC256-12DM/883 is available at Aetrix Electronics and suitable for avionics control units, tactical radio firmware storage, satellite telemetry loggers, and nuclear safety controllers requiring stable component supply with full MIL-STD-883 traceability.
Supply support for AT28HC256-12DM/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 from Atmel.
The AT28HC256 product line was designed for high-reliability embedded systems requiring radiation-tolerant, temperature-robust nonvolatile memory with deterministic write timing and hardware-assisted data integrity - especially in defense, space, and critical infrastructure applications.
FAQ
What is the maximum page write size supported by the AT28HC256-12DM/883?
The AT28HC256-12DM/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 each successive byte must be loaded within 150 µs of the previous one. Exceeding this interval triggers automatic internal programming. This capability is confirmed in Section 6.8 and Figure 6-9 of datasheet DS20006352A.
Does the AT28HC256-12DM/883 require a 12 V supply for normal operation?
No, the AT28HC256-12DM/883 operates from a single 5 V ±10% supply during standard read/write operations. A 12 V ±0.5 V level is required only for accessing the 64-byte device identification area (7FC0H–7FFFH) by raising A9 to 12 V - all other functions, including software data protection and chip erase, use standard 5 V logic levels.
How is write completion detected on the AT28HC256-12DM/883?
Write completion on the AT28HC256-12DM/883 is detectable via two hardware methods: (1) DATA polling on I/O7 - reading the last written byte returns its complement until completion, then true data; (2) Toggle-bit detection on I/O6 - the pin toggles between 0 and 1 during write, then stabilizes. Both are specified in Sections 6.14 and 6.16 of DS20006352A.
Is the AT28HC256-12DM/883 pin-compatible with commercial-grade AT28HC256 variants?
Yes, the AT28HC256-12DM/883 shares identical pinout, signal definitions, and JEDEC byte-wide footprint with commercial AT28HC256 variants (e.g., AT28HC256-12PI), including CERDIP, CLCC, Flatpack, and PGA packages. However, the /883 suffix denotes full MIL-STD-883 Class B testing - not just extended temperature - so PCB layout may require additional hermetic sealing provisions.
What endurance rating applies to the AT28HC256-12DM/883?
The AT28HC256-12DM/883 is rated for 10,000 write/erase cycles, as indicated by the "blank" endurance code in its marking (per Section 7.1 of DS20006352A). This is distinct from the "E"-marked variant (AT28HC256-12DM/883E), which guarantees 100,000 cycles. Both retain data for 10 years at +125°C.
AT28HC256-12DM/883 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Microchip Technology
- Series:
- -
- Package/Case:
- 28-CDIP (0.600", 15.24mm)
- 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:
- Through Hole
- Supplier Device Package:
- 28-CerDip
AT28HC256-12DM/883 FAQ
1.How can I place an order for AT28HC256-12DM/883 through Aetrix?
Please submit a Request for Quotation (RFQ) for AT28HC256-12DM/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 AT28HC256-12DM/883 reliable?
The price and inventory of AT28HC256-12DM/883 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for AT28HC256-12DM/883 is usually 5 days.
3.What payment methods are accepted for AT28HC256-12DM/883?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for AT28HC256-12DM/883 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for AT28HC256-12DM/883?
AT28HC256-12DM/883 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your AT28HC256-12DM/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 AT28HC256-12DM/883?
For technical support, including AT28HC256-12DM/883 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your AT28HC256-12DM/883 requirements.
6.How does Aetrix verify that AT28HC256-12DM/883 is sourced from the original manufacturer or authorized distributors?
All AT28HC256-12DM/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 AT28HC256-12DM/883 meets industry standards.
7.What is the process for return or replacement of AT28HC256-12DM/883?
All AT28HC256-12DM/883 units undergo pre-shipment inspection (PSI). If there is an issue with AT28HC256-12DM/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 AT28HC256-12DM/883 part is unused and in its original packaging.
Return procedure for AT28HC256-12DM/883:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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