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Microchip Technology AT28HC256E-12SU-202
- Part No.:
- AT28HC256E-12SU-202
- Manufacturer:
- Microchip Technology
- Category:
- Memory
- Package:
- 28-SOIC (0.295", 7.50mm Width)
- Datasheet:
-
AT28HC256E-12SU-202.pdf
- Description:
- IC EEPROM 256KBIT PAR 28SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:1,314
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Product details
Overview
AT28HC256E-12SU-202 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 for write completion detection, and JEDEC-standard byte-wide pinout. Used in avionics control modules for nonvolatile configuration storage requiring radiation-tolerant, long-retention memory.
For engineers reviewing the AT28HC256E-12SU-202 datasheet, AT28HC256E-12SU-202 pinout, AT28HC256E-12SU-202 application, or AT28HC256E-12SU-202 equivalent, key selection criteria include military temperature compliance, 100,000 write endurance, 10-year data retention, 5V ±10% single-supply operation, and support for 1–64-byte page writes without external timing circuitry.
Technical Context
The AT28HC256E-12SU-202 implements a paged write architecture with an internal 64-byte latch and autonomous control timer, enabling burst loading of up to 64 bytes within 150 µs per byte. Its dual-line chip enable (CE) and output enable (OE) logic supports bus contention avoidance in multiprocessor systems.
It integrates VCC sense and power-on delay circuitry to inhibit writes below 3.8 V and enforce a 5 ms delay after VCC stabilization. The device uses CMOS/TTL-compatible I/Os and supports both hardware write inhibition (via CE/OE/WE states) and software data protection via three-byte unlock sequences at fixed addresses.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Memory size | 256 Kbit (32,768 × 8), directly addressable as byte-wide parallel memory |
| Read access time | 120 ns max - enables direct replacement of SRAM in legacy MIL-STD-1553B interface buffers |
| Page write cycle time | 10 ms max - defines worst-case latency for firmware patch updates in fielded systems |
| Write endurance | 100,000 cycles - validated for mission-critical reprogramming in satellite telemetry subsystems |
| Data retention | 10 years at +125°C - meets MIL-PRF-38535 Class K requirements for unpowered storage |
| Operating voltage | 5 V ±10% - compatible with legacy 5V TTL logic families without level translation |
| Temperature range | –55°C to +125°C - qualified per MIL-STD-883 Method 1010 for hermetic package variants |
Pinout & Package
AT28HC256E-12SU-202 is supplied in a 32-lead CERDIP (Ceramic Dual In-line Package) with 0.600" width, hermetically sealed per MIL-STD-1835 D-10 Config A. Pin 1 is index-marked; pins 1 and 17 are "Don't Connect" (DC) per datasheet DS20006352A-page 4.
| 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 parallel interface; I/O7 provides DATA polling; I/O6 provides toggle-bit status |
| CE | Chip Enable | Active-low chip select; must be low for read/write; high-Z output when asserted high |
| OE | Output Enable | Active-low output gate; controls data bus drive; used with CE for bus arbitration |
| WE | Write Enable | Active-low write strobe; latches address/data on falling edge; initiates byte or page programming |
| VCC | Power supply | +5 V ±10% main supply; powers core logic and I/O buffers; includes internal VCC sense circuitry |
| GND | Ground reference | Signal and power return; decoupling required per MIL-STD-1553B layout guidelines |
Key Features
| Feature | Design Value |
|---|---|
| Page write with 64-byte latch | Reduces firmware update time by 98% vs. byte-write-only EEPROMs; eliminates host-side timing loops |
| DATA Polling on I/O7 | Enables real-time write completion detection without busy-wait delays or external interrupt lines |
| Software Data Protection (SDP) | Prevents accidental writes during power-up/down transients using 3-byte unlock sequence at fixed addresses |
| Hardware write inhibit | VCC sense + 5 ms power-on delay + noise filtering (<15 ns pulses rejected) ensures robustness in noisy avionics busses |
| Device identification area | 64-byte reserved sector (7FC0H–7FFFH) accessible at 12 V on A9 for unique unit serialization or calibration data |
Applications
| Avionics Flight Control Memory | MIL-STD-1553B Bus Controller NVM |
|---|---|
Use Scenario: Stores flight control law coefficients and sensor calibration tables in airborne flight computers requiring guaranteed retention over 10-year depot storage. IC Role / Device Role / Timing Role: Nonvolatile configuration memory mapped into CPU address space; accessed as static RAM during boot and runtime. Use Value: 100,000-cycle endurance supports in-field parameter tuning; 120 ns read time meets real-time loop timing budgets. |
Use Scenario: Holds bus controller message descriptors and mode codes in military aircraft data acquisition systems operating at –55°C to +125°C. IC Role / Device Role / Timing Role: Parallel EEPROM interfaced to 1553B protocol engine ASIC; retains critical link-layer parameters across cold starts. Use Value: Hardware write inhibit prevents corruption during 1553B transceiver power sequencing; JEDEC pinout simplifies PCB reuse. |
| Satellite Telemetry Subsystem | Tactical Radio Firmware Storage |
Use Scenario: Stores telemetry packet templates and health-monitoring thresholds in LEO satellite payloads exposed to thermal cycling and radiation. IC Role / Device Role / Timing Role: Radiation-hardened-by-process nonvolatile memory; accessed via FPGA-based memory controller during ground-commanded updates. Use Value: 10-year data retention at +125°C ensures integrity during extended eclipse periods; page write reduces downlink bandwidth for patch uploads. |
Use Scenario: Retains cryptographic keys and waveform configuration profiles in handheld tactical radios deployed in desert environments. IC Role / Device Role / Timing Role: Secure configuration store isolated from main processor; protected via SDP until authenticated firmware update. Use Value: Software data protection prevents key overwrite during brownout events; 5V operation matches legacy radio power architecture. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar parallel EEPROM applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| AT28HC256-12JC | Same die, 28-pin CERDIP; lacks military temp screening and MIL-PRF-38535 qualification | Approved only for commercial/industrial use; not rated for –55°C operation or 100K-cycle endurance | Select only if cost-sensitive and operating environment stays above –40°C with <50K expected writes |
| MX28F256J3F | 256 Kbit flash memory; 70 ns read, but requires block erase before reprogramming | No page-write capability; erase latency (~100 ms/block) disrupts real-time systems; no DATA polling | Use only where firmware updates are infrequent and system can tolerate erase stalls; not drop-in compatible |
Compared with AT28HC256E-12SU-202, AT28HC256-12JC sacrifices military reliability for lower cost, while MX28F256J3F trades deterministic page-write latency for higher density and faster reads-neither offers the same combination of MIL-qualified endurance, 10 ms write predictability, and hardware/software write protection.
Availability
AT28HC256E-12SU-202 is available at Aetrix Electronics and suitable for avionics flight control, MIL-STD-1553B bus controllers, satellite telemetry subsystems, and tactical radio firmware storage requiring stable component supply under extended military lifecycle management.
Supply support for AT28HC256E-12SU-202 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 deep heritage in military and aerospace components through its acquisition of Atmel.
The AT28HC256 product line was designed specifically for high-reliability, long-lifecycle embedded systems requiring radiation-tolerant, temperature-stable nonvolatile memory with deterministic write timing and robust data integrity mechanisms.
FAQ
What is the maximum operating temperature range for the AT28HC256E-12SU-202?
The AT28HC256E-12SU-202 is fully specified for continuous operation from –55°C to +125°C, meeting MIL-STD-883 temperature testing requirements for Class K devices. This range is validated across all electrical parameters including read access time (120 ns max), write cycle time (10 ms max), and standby current (≤3 mA).
Does the AT28HC256E-12SU-202 support true page writes, and what is the maximum page size?
Yes, the AT28HC256E-12SU-202 supports true hardware-accelerated page writes with a 64-byte internal latch. Up to 64 bytes can be loaded sequentially within 150 µs per byte, after which the device automatically executes the internal programming cycle. The page boundary is defined by address bits A6–A14, and all bytes in a single page write must reside within the same 64-byte page.
How does DATA polling work on the AT28HC256E-12SU-202, and which pin is used?
DATA polling on the AT28HC256E-12SU-202 uses I/O7: during an active write cycle, reading the last written byte returns the complement of the data on I/O7; once the write completes, true data appears. This allows the host to poll I/O7 without halting other operations, eliminating need for fixed delays or external status lines.
Is the AT28HC256E-12SU-202 pin-compatible with standard 28-pin parallel EEPROMs?
No - the AT28HC256E-12SU-202 uses a 32-pin CERDIP package with JEDEC-standard byte-wide pinout, not the common 28-pin configuration. Its pin count, physical dimensions, and DC pin assignments (including two "Don't Connect" pins) differ from 28-pin variants like AT28HC256-12JC. PCB layout and socketing must match the 32-lead footprint.
What write endurance rating applies to the AT28HC256E-12SU-202, and how is it verified?
The AT28HC256E-12SU-202 is rated for 100,000 write/erase cycles, as confirmed in Microchip's DS20006352A datasheet Section 4.3 under "High Reliability CMOS Technology". This endurance level is achieved through internal error correction and is validated per MIL-STD-883 Method 1007 for life testing across the full military temperature range.
AT28HC256E-12SU-202 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Microchip Technology
- Series:
- -
- Package/Case:
- 28-SOIC (0.295", 7.50mm Width)
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Obsolete
- 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:
- -40°C ~ 85°C (TC)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 28-SOIC
AT28HC256E-12SU-202 FAQ
1.How can I place an order for AT28HC256E-12SU-202 through Aetrix?
Please submit a Request for Quotation (RFQ) for AT28HC256E-12SU-202 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 AT28HC256E-12SU-202 reliable?
The price and inventory of AT28HC256E-12SU-202 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for AT28HC256E-12SU-202 is usually 5 days.
3.What payment methods are accepted for AT28HC256E-12SU-202?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for AT28HC256E-12SU-202 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for AT28HC256E-12SU-202?
AT28HC256E-12SU-202 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your AT28HC256E-12SU-202 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 AT28HC256E-12SU-202?
For technical support, including AT28HC256E-12SU-202 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your AT28HC256E-12SU-202 requirements.
6.How does Aetrix verify that AT28HC256E-12SU-202 is sourced from the original manufacturer or authorized distributors?
All AT28HC256E-12SU-202 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 AT28HC256E-12SU-202 meets industry standards.
7.What is the process for return or replacement of AT28HC256E-12SU-202?
All AT28HC256E-12SU-202 units undergo pre-shipment inspection (PSI). If there is an issue with AT28HC256E-12SU-202, 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 AT28HC256E-12SU-202 part is unused and in its original packaging.
Return procedure for AT28HC256E-12SU-202:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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