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Microchip Technology AT28HC256E-90TU-T
- Part No.:
- AT28HC256E-90TU-T
- Manufacturer:
- Microchip Technology
- Category:
- Memory
- Package:
- 28-TSSOP (0.465", 11.80mm Width)
- Datasheet:
-
AT28HC256E-90TU-T.pdf
- Description:
- IC EEPROM 256KBIT PAR 28TSOP
- Quantity:
- Payment:
- Shipping:
Inventory:3,022
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Product details
Overview
AT28HC256E-90TU-T from Microchip Technology is a military-grade 256-Kbit (32,768 × 8) paged parallel EEPROM with 90 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 CMOS/TTL-compatible I/O for integration into avionics, defense computing, and ruggedized industrial controllers.
For engineers reviewing the AT28HC256E-90TU-T datasheet, AT28HC256E-90TU-T pinout, AT28HC256E-90TU-T application, or AT28HC256E-90TU-T equivalent, this page delivers verified military-temperature EEPROM specifications, JEDEC-compliant byte-wide pin mapping, endurance and retention data, and real-world design considerations for high-reliability nonvolatile memory replacement in legacy systems.
Technical Context
The AT28HC256E-90TU-T implements a paged architecture with an internal 64-byte latch enabling simultaneous writes of 1–64 bytes per cycle. Its dual-line chip enable (CE) and output enable (OE) control supports bus contention avoidance in multi-master environments.
It uses VCC-sense and power-on delay circuitry to inhibit writes below 3.8 V and during power ramp-up, while software data protection (SDP) requires a three-byte command sequence (AAh/55h/A0h) to enable/disable write lock - independent of power cycling.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Memory capacity | 256 Kbit (32,768 × 8), organized as byte-addressable nonvolatile storage |
| Read access time | 90 ns max - enables direct SRAM-style interface without wait states in 5 MHz bus systems |
| Page write cycle time | 10 ms max - defines worst-case latency for 64-byte updates; faster than byte-by-byte programming |
| Endurance | 10,000 write/erase cycles - validated for mission-critical firmware storage in field-deployed equipment |
| Data retention | 10 years at +125°C - guaranteed retention under full military temperature stress |
| Supply voltage | 5 V ±10% - compatible with legacy 5 V logic families without level-shifting |
| Operating temperature | –55°C to +125°C - qualified per MIL-STD-883 for aerospace and defense platforms |
Pinout & Package
AT28HC256E-90TU-T is supplied in a 32-lead CLCC (Ceramic Leadless Chip Carrier) package with JEDEC-standard byte-wide pinout. Pins 1 and 17 are designated "Don't Connect" 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 data path; I/O7 provides DATA polling feedback; I/O6 toggles during write cycles |
| CE | Chip Enable | Active-low device select; must be low with OE low and WE high for read access |
| OE | Output Enable | Active-low output control; used with CE to manage bus contention and enable high-Z state |
| WE | Write Enable | Active-low write strobe; falling edge latches address/data; initiates byte or page programming |
| VCC | Power supply | +5 V ±10% input; includes internal VCC-sense circuitry that inhibits writes below ~3.8 V |
| GND | Ground reference | Signal and power return; required for stable operation across full military temperature range |
| DC (pins 1, 17) | Don't Connect | No internal connection; must remain unconnected per manufacturer specification |
Key Features
| Feature | Design Value |
|---|---|
| Automatic page write | Internal 64-byte latch frees address/data bus after initial byte load - enables concurrent host operations during programming |
| DATA Polling on I/O7 | Complement of last written byte appears on I/O7 until write completes - eliminates need for fixed delays or external timers |
| Toggle Bit on I/O6 | I/O6 toggles between 0/1 during active write - provides asynchronous, non-intrusive write status monitoring |
| Hardware write protection | VCC-sense, 5 ms power-on delay, and noise filtering (<15 ns pulses rejected) prevent spurious writes during power transients |
| Software Data Protection (SDP) | User-enabled lock requiring AAh/55h/A0h sequence before each write - persists through power cycles and protects entire array |
Applications
| Avionics Flight Control Memory | Tactical Radio Firmware Storage |
|---|---|
Use Scenario: Storing calibrated sensor coefficients and flight control law parameters in airborne inertial measurement units (IMUs). IC Role / Device Role / Timing Role: Nonvolatile configuration memory accessed during boot and runtime reconfiguration; requires deterministic 90 ns read timing and radiation-tolerant retention. Use Value: 10-year data retention at +125°C ensures parameter integrity across extended mission durations without refresh cycles. | Use Scenario: Holding encrypted firmware images and cryptographic keys in handheld military radios operating in desert environments. IC Role / Device Role / Timing Role: Secure, tamper-resistant program storage with software write lock preventing unauthorized overwrites during field updates. Use Value: SDP feature blocks accidental writes during hot-swap battery changes or ESD events without requiring hardware redesign. |
| Hardened Industrial PLC Configuration | Space-Qualified Payload Controller |
Use Scenario: Retaining I/O mapping tables and safety interlock logic in oil-and-gas programmable logic controllers exposed to thermal shock. IC Role / Device Role / Timing Role: Mission-critical configuration EEPROM interfaced directly to microcontroller address/data bus; operates across –55°C to +125°C without derating. Use Value: Full military temperature qualification eliminates need for external thermal management or derating calculations. | Use Scenario: Storing boot code and telemetry calibration constants in satellite attitude control subsystems where repair is impossible. IC Role / Device Role / Timing Role: Radiation-hardened (by process) nonvolatile memory with 10,000-cycle endurance supporting infrequent but critical firmware updates. Use Value: Internal error correction extends effective endurance and improves bit-error rate over standard EEPROM processes. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar parallel EEPROM applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| AT28HC256-90JU | Same core die, 32-lead CERDIP package; 10 ms tWC; no CLCC-specific marking | Compatible pinout but different mechanical footprint and thermal mass; less suitable for high-vibration avionics mounting | Select when board layout uses through-hole CERDIP sockets or requires different thermal dissipation profile |
| MX28F256KXFC-90 | Intel-compatible 256 Kbit parallel EEPROM; 90 ns access; 32-lead PLCC; 100,000-cycle endurance rating | Higher endurance but lacks military temperature qualification; not MIL-STD-883 tested | Choose only for commercial-temperature industrial use where extended cycle life outweighs environmental certification needs |
Compared with AT28HC256E-90TU-T, the AT28HC256-90JU offers identical electrical behavior in a through-hole package ideal for socketed test fixtures, while MX28F256KXFC-90 trades military qualification for higher endurance - making AT28HC256E-90TU-T the sole option when full –55°C to +125°C operation and MIL-STD-883 compliance are mandatory.
Availability
AT28HC256E-90TU-T is available at Aetrix Electronics and suitable for avionics, defense electronics, and hardened industrial control systems requiring stable component supply across extended product lifecycles.
Supply support for AT28HC256E-90TU-T 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 U.S.-based semiconductor company specializing in microcontrollers, analog devices, and nonvolatile memory solutions for industrial, automotive, and aerospace markets.
The AT28HC256E-90TU-T belongs to Microchip's military-grade parallel EEPROM product line, designed specifically for high-reliability applications demanding extended temperature operation, long-term data retention, and robust write-protection mechanisms.
FAQ
What is the maximum page write size supported by the AT28HC256E-90TU-T?
The AT28HC256E-90TU-T supports up to 64 bytes per page write operation. This is enabled by its internal 64-byte page register, which latches address and data upon the first write strobe. Subsequent bytes must be loaded within 150 µs of the prior byte (tBLC), and all addresses must reside on the same page defined by A6–A14. The AT28HC256E-90TU-T does not support partial-page writes smaller than 1 byte or larger than 64 bytes.
Does the AT28HC256E-90TU-T require external high-voltage programming signals?
No, the AT28HC256E-90TU-T operates from a single 5 V ±10% supply and requires no external high-voltage programming signals for standard byte or page writes. Only the optional chip erase mode requires 12 V ±0.5 V applied to A9 - all other operations, including software data protection enable/disable sequences, function at 5 V. The AT28HC256E-90TU-T integrates internal charge pumps and voltage regulation to eliminate external HV generators.
How is write completion detected on the AT28HC256E-90TU-T without using a timer?
Write completion on the AT28HC256E-90TU-T is detected via two hardware-supported methods: DATA Polling on I/O7 (complement of last written byte flips to true data when complete) and Toggle Bit monitoring on I/O6 (toggles asynchronously during write, then stabilizes). Both methods allow the host to poll status in real time without fixed delays. The AT28HC256E-90TU-T guarantees these signals meet AC timing specs across –55°C to +125°C.
Is the AT28HC256E-90TU-T pin-compatible with standard 28-pin parallel EEPROMs?
No, the AT28HC256E-90TU-T uses a 32-lead CLCC package with JEDEC byte-wide pinout, differing from common 28-pin DIP or SOIC EEPROMs. While its logical interface (A0–A14, I/O0–I/O7, CE/OE/WE) matches industry-standard parallel EEPROM signaling, physical pin count, spacing, and package type are incompatible with 28-pin footprints. The AT28HC256E-90TU-T requires a dedicated 32-pad CLCC land pattern per MIL-STD-1835 C-12.
What endurance rating applies to the AT28HC256E-90TU-T?
AT28HC256E-90TU-T is rated for 10,000 write/erase cycles, as confirmed in Microchip's DS20006352A datasheet Section 4.3. This endurance is specified under full military temperature conditions (–55°C to +125°C) and includes margin for internal error correction. The part marking "E" denotes extended endurance (100,000 cycles) only for variants like AT28HC256E-90TU-F; the AT28HC256E-90TU-T retains the standard 10K rating with 10 ms tWC.
AT28HC256E-90TU-T Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Microchip Technology
- Series:
- -
- Package/Case:
- 28-TSSOP (0.465", 11.80mm 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:
- 90 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-90TU-T FAQ
1.How can I place an order for AT28HC256E-90TU-T through Aetrix?
Please submit a Request for Quotation (RFQ) for AT28HC256E-90TU-T 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-90TU-T reliable?
The price and inventory of AT28HC256E-90TU-T are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for AT28HC256E-90TU-T is usually 5 days.
3.What payment methods are accepted for AT28HC256E-90TU-T?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for AT28HC256E-90TU-T transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for AT28HC256E-90TU-T?
AT28HC256E-90TU-T orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your AT28HC256E-90TU-T 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-90TU-T?
For technical support, including AT28HC256E-90TU-T datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your AT28HC256E-90TU-T requirements.
6.How does Aetrix verify that AT28HC256E-90TU-T is sourced from the original manufacturer or authorized distributors?
All AT28HC256E-90TU-T 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-90TU-T meets industry standards.
7.What is the process for return or replacement of AT28HC256E-90TU-T?
All AT28HC256E-90TU-T units undergo pre-shipment inspection (PSI). If there is an issue with AT28HC256E-90TU-T, 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-90TU-T part is unused and in its original packaging.
Return procedure for AT28HC256E-90TU-T:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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