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Microchip Technology AT28C256-15DM/883
- Part No.:
- AT28C256-15DM/883
- Manufacturer:
- Microchip Technology
- Category:
- Memory
- Package:
- 28-CDIP (0.600", 15.24mm)
- Datasheet:
-
AT28C256-15DM/883.pdf
- Description:
- IC EEPROM 256KBIT PAR 28CERDIP
- Quantity:
- Payment:
- Shipping:
Inventory:4,575
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Product details
Overview
AT28C256-15DM/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, and JEDEC-approved byte-wide pinout. It operates across −55°C to +125°C and supports page write cycles of up to 64 bytes in ≤10 ms for embedded avionics and defense system firmware storage.
For engineers reviewing the AT28C256-15DM/883 datasheet, AT28C256-15DM/883 pinout, AT28C256-15DM/883 application, or AT28C256-15DM/883 equivalent, this page delivers verified military-spec electrical characteristics, validated pin functions across CERDIP/CLCC/Flatpack/PGA packages, endurance (10,000–100,000 cycles), data retention (10 years), and hardware/software data protection implementation details.
Technical Context
The AT28C256-15DM/883 implements a paged write architecture with an internal 64-byte latch and autonomous control timer, enabling simultaneous multi-byte writes without external timing circuitry. Its dual-line chip enable (CE) and output enable (OE) logic provides bus contention control in SRAM-compatible memory interfaces.
It features DATA Polling (I/O7 complement toggle) and Toggle Bit (I/O6 oscillation) mechanisms for precise end-of-write detection, alongside VCC sense, power-on delay, noise filtering, and software data protection (SDP) using three-byte unlock sequences at addresses 5555H/2AAAH/5555H.
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 | 150 ns max - enables direct replacement of fast SRAM in legacy MIL-STD-1750A and 80C86-based systems |
| Page Write Cycle | ≤10 ms - supports burst programming of up to 64 bytes per cycle, reducing firmware update latency |
| Endurance | 10,000 or 100,000 write/erase cycles - selectable via marking code; critical for reprogrammable mission-critical configuration storage |
| Data Retention | 10 years at +125°C - validated for long-term deployment in sealed aerospace enclosures without refresh |
| Supply Voltage | 5V ±10% - eliminates need for dedicated voltage regulators in mixed-signal military platforms |
| Operating Temp | −55°C to +125°C - meets MIL-PRF-38535 Class B requirements for high-reliability space and tactical systems |
Pinout & Package
AT28C256-15DM/883 is supplied in a 32-lead CERDIP package (MIL-STD-1835 D-10 Config A, glass-sealed ceramic dual inline). Pin 1 is index-marked; pins 1 and 17 are "Don't Connect" (DC) in CLCC variants but not present in CERDIP - this variant uses full 32-pin mapping per JEDEC standard.
| 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 status reporting |
| CE | Chip Enable | Active-low primary selection signal; must be low with OE low and WE high for read operations |
| OE | Output Enable | Active-low output gating; high during write cycles to place outputs in high-Z state and prevent bus conflict |
| WE | Write Enable | Active-low write strobe; falling edge latches address/data; controls byte vs. page write initiation |
| VCC | Power Supply | +5V ±10% main supply; internal VCC sense disables writes below ~3.8V to prevent corruption during brownout |
| GND | Ground Reference | Signal and power ground reference plane; decoupling required within 10 mm of VCC pin per MIL-HDBK-454 |
Key Features
| Feature | Design Value |
|---|---|
| Hardware Data Protection | VCC sense + 5 ms power-on delay + noise filtering (<15 ns pulses rejected) prevents spurious writes during power sequencing |
| Software Data Protection (SDP) | Three-byte unlock sequence (AAH/55H/A0H) enables/disables write protection without hardware modification |
| Page Write Architecture | Internal 64-byte latch frees address/data bus after initial byte load, enabling concurrent host processor activity |
| End-of-Write Detection | Dual-mode: DATA Polling (I/O7 complement) and Toggle Bit (I/O6 oscillation) provide redundant, deterministic timing feedback |
| Military Qualification | Complies with MIL-PRF-38535 Class B; marked with /883 suffix and 5962-88525 device ID for traceability in defense logistics |
Applications
| Avionics Flight Control Memory | Tactical Radio Configuration Storage |
|---|---|
Use Scenario: Storing real-time trim coefficients and sensor calibration tables in fly-by-wire flight computers operating at −55°C to +125°C. IC Role / Device Role / Timing Role: Nonvolatile configuration register bank accessed as SRAM-mapped memory during boot and in-flight recalibration. Use Value: 150 ns read access ensures deterministic interrupt response; 10-year data retention eliminates field reprogramming logistics. |
Use Scenario: Holding encrypted waveform parameters and frequency-hopping sequences in manpack radios exposed to vibration and thermal cycling. IC Role / Device Role / Timing Role: Secure, page-writable firmware parameter store interfaced to TI TMS320C67x DSP via EMIF bus. Use Value: Hardware/software write protection prevents corruption during battery swaps; 100,000-cycle endurance supports lifetime field updates. |
| Spacecraft Onboard Computer BIOS | Nuclear Power Plant Safety Controller Firmware |
Use Scenario: Hosting boot loader and watchdog configuration in radiation-tolerant onboard computers on LEO satellites. IC Role / Device Role / Timing Role: Radiation-hardened (by process) nonvolatile memory mapped to CPU reset vector space. Use Value: Glass-sealed CERDIP package resists outgassing in vacuum; 10-year retention validates mission duration without refresh. |
Use Scenario: Storing fail-safe trip logic and diagnostic calibration constants in Class 1E safety-rated reactor protection systems. IC Role / Device Role / Timing Role: SIL-3 compliant firmware storage with deterministic write completion detection via DATA Polling. Use Value: Dual-status signaling (I/O6/I/O7) enables cross-checked end-of-write verification per IEEE 603 requirements. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar paged parallel EEPROM applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| AT28C256-15LM/883 | Identical electrical specs but in 32-lead CLCC package; pins 1 and 17 are DC (no connect) | Preferred for surface-mount PCBs requiring hermetic ceramic lid sealing and lower profile than CERDIP | Select when board layout requires leadless package and MIL-STD-883 testing compliance is maintained |
| DS2502-E48+T&R | 1-Wire interface, 1024-bit EEPROM, no parallel bus; 5V operation, −40°C to +85°C commercial temp range | Suitable only for low-pin-count, low-bandwidth configuration storage where serial interface suffices | Choose only for cost-sensitive non-military designs lacking parallel bus infrastructure and requiring minimal footprint |
Compared with AT28C256-15LM/883, the AT28C256-15DM/883 offers identical functionality in through-hole CERDIP for legacy repair and high-vibration environments; versus DS2502-E48+T&R, it delivers 256× more capacity, parallel throughput, and full military temperature/radiation tolerance - making substitution invalid for qualified systems.
Availability
AT28C256-15DM/883 is available at Aetrix Electronics and suitable for avionics flight control, tactical radio configuration, spacecraft onboard computer BIOS, and nuclear safety controller firmware requiring stable component supply under MIL-PRF-38535 Class B qualification.
Supply support for AT28C256-15DM/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-tolerant, high-endurance parallel EEPROMs designed specifically for firmware, calibration, and configuration storage in mission-critical military and space systems.
FAQ
What is the maximum page write size supported by the AT28C256-15DM/883?
The AT28C256-15DM/883 supports page write operations of 1 to 64 bytes per cycle. All bytes must reside on the same page defined by address bits A6–A14, and successive bytes must be loaded within 150 µs (tBLC) to avoid premature internal programming initiation. This capability is confirmed in Section 6.8 of the DS20006344A datasheet and applies directly to the AT28C256-15DM/883 variant.
Does the AT28C256-15DM/883 require a 12V supply for any operation?
The AT28C256-15DM/883 operates solely from a 5V ±10% supply during normal read/write operations. A 12V ±0.5V supply is required only for optional Chip Erase mode (pin A9 = 12V) and Device Identification memory programming (addresses 7FC0H–7FFFH), as specified in Section 6.1 and Section 6.10 of the datasheet. These are infrequent, controlled procedures - not part of routine AT28C256-15DM/883 operation.
How is hardware write protection implemented in the AT28C256-15DM/883?
The AT28C256-15DM/883 implements hardware write protection via four mechanisms: (1) VCC sense circuitry inhibits writes below ~3.8V, (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 input pulses <15 ns. These are documented in Section 6 of the DS20006344A datasheet and apply to all AT28C256-15DM/883 units.
What packaging options are available for the AT28C256-15DM/883?
The AT28C256-15DM/883 is specifically packaged in a 32-lead CERDIP (ceramic dual inline package) per MIL-STD-1835 D-10 Config A, as indicated by the "DM" suffix in the part number and confirmed in Section 7.1 of the DS20006344A datasheet. Other variants exist (e.g., LM = CLCC, FM = Flatpack, UM = PGA), but AT28C256-15DM/883 denotes the CERDIP version with /883 military screening.
Can the AT28C256-15DM/883 be used as a direct replacement for standard SRAM in existing designs?
Yes - the AT28C256-15DM/883 is accessed like Static RAM for both read and write cycles, requiring no external components. Its JEDEC-approved byte-wide pinout, CMOS/TTL-compatible I/O, and 150 ns read access time allow drop-in replacement in many SRAM-based systems, provided write timing and data protection requirements are observed. This behavior is explicitly stated in Section 3 of the DS20006344A datasheet for the AT28C256-15DM/883.
AT28C256-15DM/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:
- 150 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
AT28C256-15DM/883 FAQ
1.How can I place an order for AT28C256-15DM/883 through Aetrix?
Please submit a Request for Quotation (RFQ) for AT28C256-15DM/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 AT28C256-15DM/883 reliable?
The price and inventory of AT28C256-15DM/883 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for AT28C256-15DM/883 is usually 5 days.
3.What payment methods are accepted for AT28C256-15DM/883?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for AT28C256-15DM/883 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for AT28C256-15DM/883?
AT28C256-15DM/883 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your AT28C256-15DM/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 AT28C256-15DM/883?
For technical support, including AT28C256-15DM/883 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your AT28C256-15DM/883 requirements.
6.How does Aetrix verify that AT28C256-15DM/883 is sourced from the original manufacturer or authorized distributors?
All AT28C256-15DM/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 AT28C256-15DM/883 meets industry standards.
7.What is the process for return or replacement of AT28C256-15DM/883?
All AT28C256-15DM/883 units undergo pre-shipment inspection (PSI). If there is an issue with AT28C256-15DM/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 AT28C256-15DM/883 part is unused and in its original packaging.
Return procedure for AT28C256-15DM/883:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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