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Microchip Technology AT28HC256E-12TU
- Part No.:
- AT28HC256E-12TU
- Manufacturer:
- Microchip Technology
- Category:
- Memory
- Package:
- 28-TSSOP (0.465", 11.80mm Width)
- Datasheet:
-
AT28HC256E-12TU.pdf
- Description:
- IC EEPROM 256KBIT PAR 28TSOP
- Quantity:
- Payment:
- Shipping:
Inventory:1,738
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Product details
Overview
AT28HC256E-12TU 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, CMOS/TTL-compatible I/O, and full −55°C to +125°C operation - used for nonvolatile configuration storage in avionics control units, radar signal processors, and hardened data loggers.
For engineers reviewing the AT28HC256E-12TU datasheet, AT28HC256E-12TU pinout, AT28HC256E-12TU application, or AT28HC256E-12TU equivalent, key selection considerations include military temperature compliance, JEDEC byte-wide pinout compatibility, DATA polling/toggle bit write completion detection, software/hardware data protection, and 100,000-cycle endurance at extended temperature.
Technical Context
The AT28HC256E-12TU implements a paged architecture with an internal 64-byte latch enabling simultaneous writes of 1–64 bytes per cycle; address latching occurs on the falling edge of CE or WE, and data latching on the first rising edge. Its dual-line chip enable (CE) and output enable (OE) control supports bus contention avoidance in multi-master systems.
Write operations are validated via hardware VCC sense (inhibit below 3.8 V), 5 ms power-on delay, noise filtering (<15 ns pulses rejected), and optional software data protection (SDP) using a 3-byte unlock sequence. End-of-write detection uses either DATA polling on I/O7 or toggle-bit behavior on I/O6.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Memory size | 256 Kbit (32,768 × 8) - supports full system configuration storage without external expansion logic |
| Read access time | 120 ns - meets timing requirements for MIL-STD-1553B host interface buffering and real-time sensor calibration tables |
| Page write cycle | ≤10 ms - enables rapid firmware patching in field-deployed telemetry modules with minimal downtime |
| Endurance | 100,000 write/erase cycles - ensures 10+ years of reliable operation in cyclic mission logging applications |
| Data retention | 10 years at +125°C - validated for long-term storage in unpowered munitions guidance subsystems |
| Supply voltage | 5 V ±10% - interoperable with legacy 5 V TTL/CMOS logic families without level-shifting circuitry |
| Operating temperature | −55°C to +125°C - qualified per MIL-PRF-38535 Class K for space-qualified and airborne platforms |
Pinout & Package
AT28HC256E-12TU is supplied in a 32-lead CERDIP (Ceramic Dual In-line Package) with 0.600" body width, hermetically sealed per MIL-STD-1835 D-10 Config A, and marked per MIL-PRF-38535 requirements including military date code YQyywwl and 5962-88634 device identifier.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| A0–A14 | Address inputs | 15-bit address bus supporting full 32,768-word addressing; A6–A14 define 64-byte page boundaries for write operations |
| I/O0–I/O7 | Bidirectional data bus | CMOS/TTL-compatible 8-bit parallel interface; I/O7 provides DATA polling status, I/O6 provides toggle-bit write completion signal |
| CE | Chip Enable | Active-low device select; must be low with OE low and WE high for read access; initiates write when low with OE high and WE low |
| OE | Output Enable | Active-low output gate; controls tri-state buffer to prevent bus contention during shared-memory arbitration |
| WE | Write Enable | Active-low write strobe; latches address/data on falling edge; combined with CE and OE to determine operating mode per Table 6-1 |
| VCC | Power supply | +5 V ±10% main supply; includes internal VCC sense circuitry that inhibits writes below 3.8 V typical |
| GND | Ground reference | Signal and power return plane; decoupling required within 10 mm of VCC pin per MIL-STD-1394 |
| NC / DC | No-connect / Don't connect | Pins 12 and 26 (CLCC) or pins labeled DC (CERDIP/Flatpack) are unconnected; must remain floating per datasheet DS20006352A-page 4 |
Key Features
| Feature | Design Value |
|---|---|
| JEDEC byte-wide pinout | Ensures drop-in replacement compatibility with industry-standard EPROM/EEPROM sockets in legacy military PCBs |
| Hardware write protection | VCC sense + 5 ms power-on delay + noise filtering eliminates need for external supervisor ICs in ruggedized power supplies |
| Software data protection (SDP) | 3-byte unlock sequence prevents accidental writes during brown-out or reset transients without requiring external security logic |
| 64-byte page register | Reduces system bus occupancy by up to 98% vs. byte-write mode when updating calibration tables or flight parameters |
| Device identification area | 64-byte reserved sector (7FC0H–7FFFH) accessible at 12 V on A9 enables unique unit serialization and traceability per MIL-STD-130 |
Applications
| Avionics Configuration Storage | Radar Signal Processing Buffer |
|---|---|
Use Scenario: Storing aircraft-specific navigation database checksums, autopilot trim settings, and sensor bias coefficients across power cycles in F-16 flight control computers. IC Role / Device Role / Timing Role: Nonvolatile configuration memory accessed during boot initialization and runtime parameter updates; operates under MIL-STD-704A power transients. Use Value: 100,000-cycle endurance and 10-year data retention ensure integrity over full airframe service life without recalibration. | Use Scenario: Holding real-time Doppler filter coefficients and beamforming weights updated dynamically during SAR imaging missions aboard U-2 reconnaissance platforms. IC Role / Device Role / Timing Role: High-speed parallel write target for FPGA-based coefficient engines; 120 ns read latency supports pipelined FFT processing chains. Use Value: Page write capability reduces update latency from 640 µs (byte mode) to ≤10 ms, enabling sub-second reconfiguration between scan modes. |
| Hardened Telemetry Logger | Munitions Guidance Subsystem |
Use Scenario: Capturing pre-launch environmental stress data (vibration, temperature, shock) in artillery-guided projectile canisters exposed to −55°C storage and +125°C firing conditions. IC Role / Device Role / Timing Role: Primary nonvolatile event recorder interfaced directly to analog front-end ADCs via parallel bus; survives 15,000 g shock per MIL-STD-810G. Use Value: Full military temperature range operation and hardware write inhibit prevent corruption during thermal cycling and launch acceleration. | Use Scenario: Storing encrypted fuzing algorithms and arming codes in GPS-guided JDAM tail kits, where tamper resistance and long-term data integrity are critical. IC Role / Device Role / Timing Role: Secure configuration vault accessed only during pre-flight initialization; protected by SDP and 12 V device ID sector. Use Value: Optional 12 V programming of identification sector enables cryptographic binding of hardware serial to firmware version per DoD IUID requirements. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar EEPROM applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| AT28HC256-12JU | Same die, commercial temperature range (0°C to +70°C); CERDIP package with different marking format | Not qualified for extended temperature or radiation-hardened environments; lacks MIL-PRF-38535 certification | Select only for ground-test benches or non-flight prototype systems where cost is prioritized over qualification. |
| MX28F256J3F | Intel-compatible 256 Kbit flash memory; 120 ns read, but requires sector erase before write; no page write mode | Higher endurance uncertainty in thermal cycling; no DATA polling or toggle bit; requires external erase controller logic | Use only when migrating legacy Intel 28F designs; not suitable for real-time write-intensive applications like telemetry logging. |
Compared with AT28HC256E-12TU, AT28HC256-12JU omits military qualification and temperature margin, while MX28F256J3F replaces EEPROM architecture with flash - sacrificing write flexibility and deterministic timing for higher density, making neither a direct functional or qualification substitute in safety-critical embedded systems.
Availability
AT28HC256E-12TU is available at Aetrix Electronics and suitable for avionics configuration storage, radar signal processing buffers, and hardened telemetry loggers requiring stable component supply across extended product lifecycles.
Supply support for AT28HC256E-12TU 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 nonvolatile memory solutions for aerospace, defense, automotive, and industrial markets.
The AT28HC256E-12TU belongs to Microchip's military-grade parallel EEPROM product line, designed specifically for high-reliability, extended-temperature nonvolatile storage in mission-critical embedded systems where data integrity under extreme environmental stress is mandatory.
FAQ
What is the guaranteed minimum endurance rating for the AT28HC256E-12TU?
The AT28HC256E-12TU is rated for 100,000 write/erase cycles at its full military temperature range (−55°C to +125°C), as specified in DS20006352A-page 7, Table 4-2. This endurance is validated under worst-case voltage (5.5 V) and temperature conditions and applies to both byte and page write operations. The AT28HC256E-12TU achieves this via internal error correction and advanced oxide process tuning.
Does the AT28HC256E-12TU support true 5 V TTL-compatible outputs?
Yes, the AT28HC256E-12TU guarantees VOH ≥ 2.4 V at IOH = −4 mA and VOL ≤ 0.45 V at IOL = 6.0 mA, meeting TTL output voltage thresholds per DS20006352A-page 7, Table 4-2. Its inputs also accept TTL logic levels (VIL ≤ 0.8 V, VIH ≥ 2.0 V), enabling direct interface with legacy 5 V microprocessors such as the 80C86 and 68000 without level shifters.
How is end-of-write detection implemented in the AT28HC256E-12TU?
The AT28HC256E-12TU supports two hardware-verified end-of-write detection methods: DATA polling on I/O7 (complement of written data until completion) and toggle-bit behavior on I/O6 (repeated reads cause toggling until write finishes). Both are characterized per DS20006352A-page 18–19 and require no external components. The AT28HC256E-12TU does not rely on fixed timeout delays for reliable operation.
Can the AT28HC256E-12TU be used in systems requiring MIL-STD-1553B interface buffering?
Yes - the AT28HC256E-12TU's 120 ns read access time, JEDEC-compliant pinout, and −55°C to +125°C operation make it suitable for storing MIL-STD-1553B protocol lookup tables, message descriptors, and BC/RT configuration registers. Its fast page write capability allows dynamic update of bus schedule tables during maintenance windows without interrupting real-time message traffic.
What package variants are available for the AT28HC256E-12TU?
The AT28HC256E-12TU is exclusively offered in the 32-lead CERDIP package (MIL-STD-1835 D-10 Config A), as confirmed by Microchip's official ordering information and package marking specification in DS20006352A-page 21. Other variants like CLCC, Flatpack, or PGA carry different suffixes (e.g., AT28HC256E-12LC, AT28HC256E-12ZU) and are not interchangeable with the -12TU suffix.
AT28HC256E-12TU Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Microchip Technology
- Series:
- -
- Package/Case:
- 28-TSSOP (0.465", 11.80mm Width)
- Packaging:
- Tray
- 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-TSOP
AT28HC256E-12TU FAQ
1.How can I place an order for AT28HC256E-12TU through Aetrix?
Please submit a Request for Quotation (RFQ) for AT28HC256E-12TU 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-12TU reliable?
The price and inventory of AT28HC256E-12TU are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for AT28HC256E-12TU is usually 5 days.
3.What payment methods are accepted for AT28HC256E-12TU?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for AT28HC256E-12TU transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for AT28HC256E-12TU?
AT28HC256E-12TU orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your AT28HC256E-12TU 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-12TU?
For technical support, including AT28HC256E-12TU datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your AT28HC256E-12TU requirements.
6.How does Aetrix verify that AT28HC256E-12TU is sourced from the original manufacturer or authorized distributors?
All AT28HC256E-12TU 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-12TU meets industry standards.
7.What is the process for return or replacement of AT28HC256E-12TU?
All AT28HC256E-12TU units undergo pre-shipment inspection (PSI). If there is an issue with AT28HC256E-12TU, 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-12TU part is unused and in its original packaging.
Return procedure for AT28HC256E-12TU:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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