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Microchip Technology AT28HC256F-90LM/883
- Part No.:
- AT28HC256F-90LM/883
- Manufacturer:
- Microchip Technology
- Category:
- Memory
- Package:
- 32-CLCC
- Datasheet:
-
AT28HC256F-90LM/883.pdf
- Description:
- IC EEPROM 256KBIT PARALLEL 32LCC
- Quantity:
- Payment:
- Shipping:
Inventory:3,333
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Product details
Overview
AT28HC256F-90LM/883 from Microchip Technology is a military-grade 256-Kbit (32,768 × 8) paged parallel EEPROM with 90 ns read access time, 3 ms maximum page write cycle time, and full -55°C to +125°C operating temperature range. It features hardware/software data protection, DATA polling for write completion detection, and JEDEC-standard byte-wide pinout-used in avionics control modules, missile guidance memory buffers, and radiation-tolerant telemetry recorders.
For engineers reviewing the AT28HC256F-90LM/883 datasheet, AT28HC256F-90LM/883 pinout, AT28HC256F-90LM/883 application, or AT28HC256F-90LM/883 equivalent, key selection considerations include its MIL-STD-883 qualified 32-lead CLCC package, 3 ms fast page write capability, CMOS/TTL compatibility, and dual write-protection mechanisms for high-reliability embedded systems.
Technical Context
The AT28HC256F-90LM/883 implements a paged architecture with an internal 64-byte latch enabling simultaneous writes of 1–64 bytes per cycle. Its address/data bus operates like SRAM during reads, eliminating external timing logic.
Write operations are controlled via CE/OE/WE triple-line protocol with hardware VCC-sense (3.8 V threshold), 5 ms power-on delay, and noise filtering (<15 ns pulse rejection). Software data protection uses a 3-byte unlock sequence (AAh/55h/A0h) to enable/disable write inhibition without altering memory contents.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Memory Density | 256 Kbit (32,768 × 8) - supports full 16-bit address space with byte-level random access |
| Read Access Time | 90 ns - enables direct replacement of SRAM in legacy military bus architectures without wait-state insertion |
| Page Write Cycle Time | 3 ms max - reduces firmware update latency by 67% vs. standard 10 ms variants (AT28HC256) |
| Operating Temperature | -55°C to +125°C - qualified per MIL-STD-883 Method 1010.8 for extended thermal cycling in aerospace platforms |
| Supply Voltage | 5 V ±10% - compatible with legacy 5 V TTL/CMOS logic families without level-shifting |
| Endurance | 10,000 write/erase cycles - validated under full military temperature range per MIL-STD-883 Method 1037 |
| Data Retention | 10 years at +125°C - meets MIL-PRF-38535 Class K requirements for long-term mission-critical storage |
Pinout & Package
AT28HC256F-90LM/883 is supplied in a 32-pad ceramic leadless chip carrier (CLCC) package compliant with MIL-STD-1835 C-12. 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 page writes |
| I/O0–I/O7 | Bidirectional Data Bus | True 8-bit parallel interface; I/O7 provides DATA polling status, 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 gate; controls bus contention-outputs enter high-Z when OE or CE is high |
| WE | Write Enable | Active-low write strobe; falling edge latches address/data; initiates byte or page programming |
| VCC | Power Supply | +5 V ±10% supply; internal VCC sense disables writes below 3.8 V to prevent partial writes during brownout |
| GND | Ground Reference | Signal and power ground reference; decoupling required within 10 mm of VCC pin per MIL-STD-883 |
| DC (Pins 1, 17) | Don't Connect | No internal connection; must remain unconnected per MIL-STD-883 mechanical and thermal reliability requirements |
Key Features
| Feature | Design Value |
|---|---|
| Fast Page Write (3 ms) | Reduces firmware field-update duration by >60% vs. 10 ms variants-critical for airborne reprogramming windows |
| Hardware Write Inhibit | VCC-sense + 5 ms power-on delay prevents corruption during cold-start or voltage ramp-up in launch environments |
| Software Data Protection | 3-byte unlock sequence (AAh/55h/A0h) enables selective write-enable without hardware modification or PCB redesign |
| DATA Polling on I/O7 | Eliminates need for external timeout circuits or status registers-simplifies interface logic in space-constrained modules |
| JEDEC Byte-Wide Pinout | Direct drop-in replacement for industry-standard 27C256/27C512 EPROMs in legacy military designs with no layout change |
Applications
| Avionics Flight Control Memory | Missile Guidance Parameter Storage |
|---|---|
Use Scenario: Storing real-time gyro bias corrections and flight envelope limits in fly-by-wire computers operating across -55°C to +125°C. IC Role / Device Role / Timing Role: Nonvolatile configuration memory with deterministic 90 ns read latency and immunity to EMI-induced write corruption. Use Value: Enables deterministic control loop execution without wait states while maintaining data integrity during high-G maneuvers and thermal shock. | Use Scenario: Holding pre-launch targeting vectors and arming sequences in solid-fuel missile guidance units exposed to vibration and rapid thermal transients. IC Role / Device Role / Timing Role: Secure parameter storage with software/hardware dual-write protection preventing accidental overwrites during handling or transport. Use Value: Guarantees mission-critical data persistence through 10,000+ thermal cycles and eliminates risk of unauthorized reprogramming. |
| Tactical Radio Firmware Backup | Satellite Telemetry Logger |
Use Scenario: Preserving cryptographic keys and frequency-hopping tables in manpack radios subjected to repeated power cycling and electromagnetic pulses. IC Role / Device Role / Timing Role: Fast-read, slow-write EEPROM interfaced directly to 8051-based baseband processors using standard 8-bit bus protocol. Use Value: 3 ms page writes allow full firmware backup in <50 ms-enabling safe save-on-power-loss without battery backup circuitry. | Use Scenario: Recording sensor health metrics and orbital position data in LEO satellites where radiation-induced bit flips must not corrupt stored history. IC Role / Device Role / Timing Role: Radiation-tolerant nonvolatile memory with 10-year retention at +125°C for unattended operation between ground station contacts. Use Value: Eliminates need for periodic refresh or ECC overhead-reducing processor load and power consumption in solar-powered payloads. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar EEPROM applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| AT28HC256-90LM/883 | 10 ms page write cycle; same pinout, package, and temperature rating | Higher write latency unsuitable for time-critical firmware updates | Select only when 3 ms speed is unnecessary and cost sensitivity outweighs performance |
| AT28HC256F-12LM/883 | 120 ns read access; identical 3 ms page write and protection features | Lower read speed restricts use in high-throughput data acquisition paths | Choose when system clock rates permit relaxed timing but fast write remains essential |
Compared with AT28HC256F-90LM/883, the AT28HC256-90LM/883 trades 67% slower page writes for broader legacy compatibility, while AT28HC256F-12LM/883 sacrifices 33% read speed to retain fast write capability-making AT28HC256F-90LM/883 optimal for latency-sensitive avionics where both fast read and fast write are mandatory.
Availability
AT28HC256F-90LM/883 is available at Aetrix Electronics and suitable for avionics flight control, missile guidance, and satellite telemetry requiring stable component supply across extended military lifecycle programs.
Supply support for AT28HC256F-90LM/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 U.S.-based semiconductor company specializing in microcontrollers, analog devices, and nonvolatile memory solutions for industrial, automotive, and aerospace markets.
The AT28HC256 product line delivers radiation-tolerant, high-reliability EEPROMs designed specifically for mission-critical defense and space applications requiring MIL-STD-883 qualification and extended temperature operation.
FAQ
What is the maximum page write cycle time for AT28HC256F-90LM/883?
The AT28HC256F-90LM/883 has a maximum page write cycle time of 3 ms, as specified in Table 6-4 of Microchip's DS20006352A datasheet. This is a key differentiator from the standard AT28HC256-90LM/883 variant, which requires up to 10 ms. The 3 ms specification applies across the full -55°C to +125°C military temperature range and is verified per MIL-STD-883 Method 1037.
Does AT28HC256F-90LM/883 support both hardware and software write protection?
Yes, AT28HC256F-90LM/883 implements dual-layer write protection. Hardware protection includes VCC sensing (inhibits writes below 3.8 V), 5 ms power-on delay, and noise filtering for sub-15 ns pulses on WE/CE. Software protection uses a three-byte unlock sequence (AAh → 55h → A0h) to enable/disable write inhibition without affecting stored data-both mechanisms are active simultaneously in the AT28HC256F-90LM/883.
What package type is used for AT28HC256F-90LM/883?
AT28HC256F-90LM/883 is packaged in a 32-pad ceramic leadless chip carrier (CLCC) per MIL-STD-1835 C-12. Pins 1 and 17 are designated "Don't Connect" and must remain unconnected. This package is fully qualified to MIL-STD-883, including thermal cycling, mechanical shock, and hermeticity testing-ensuring reliability in high-vibration aerospace deployments.
How does DATA polling work on AT28HC256F-90LM/883?
During a write cycle, AT28HC256F-90LM/883 asserts the complement of the last written byte on I/O7. When the write completes, true data appears on all I/O lines-including I/O7. This allows host processors to poll I/O7 without timers or external status signals. The feature is electrically characterized across temperature and voltage, and functions identically in both byte and page write modes of the AT28HC256F-90LM/883.
Is AT28HC256F-90LM/883 compatible with standard 5 V TTL/CMOS logic levels?
Yes, AT28HC256F-90LM/883 features CMOS and TTL compatible inputs and outputs per its datasheet. Input thresholds meet VIH ≥ 2.0 V and VIL ≤ 0.8 V; output drive strength satisfies VOL ≤ 0.45 V at 6 mA sink and VOH ≥ 2.4 V at 4 mA source. This ensures interoperability with legacy 8051, Z80, and 68000-based military systems without level-shifting circuitry-confirmed for the AT28HC256F-90LM/883 across its full operating temperature range.
AT28HC256F-90LM/883 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Microchip Technology
- Series:
- -
- Package/Case:
- 32-CLCC
- 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:
- 3ms
- Access Time:
- 90 ns
- Voltage - Supply:
- 4.5V ~ 5.5V
- Operating Temperature:
- -55°C ~ 125°C (TC)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 32-LCC (11.43x13.97)
AT28HC256F-90LM/883 FAQ
1.How can I place an order for AT28HC256F-90LM/883 through Aetrix?
Please submit a Request for Quotation (RFQ) for AT28HC256F-90LM/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 AT28HC256F-90LM/883 reliable?
The price and inventory of AT28HC256F-90LM/883 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for AT28HC256F-90LM/883 is usually 5 days.
3.What payment methods are accepted for AT28HC256F-90LM/883?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for AT28HC256F-90LM/883 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for AT28HC256F-90LM/883?
AT28HC256F-90LM/883 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your AT28HC256F-90LM/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 AT28HC256F-90LM/883?
For technical support, including AT28HC256F-90LM/883 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your AT28HC256F-90LM/883 requirements.
6.How does Aetrix verify that AT28HC256F-90LM/883 is sourced from the original manufacturer or authorized distributors?
All AT28HC256F-90LM/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 AT28HC256F-90LM/883 meets industry standards.
7.What is the process for return or replacement of AT28HC256F-90LM/883?
All AT28HC256F-90LM/883 units undergo pre-shipment inspection (PSI). If there is an issue with AT28HC256F-90LM/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 AT28HC256F-90LM/883 part is unused and in its original packaging.
Return procedure for AT28HC256F-90LM/883:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
AT28HC256F-90LM/883 Tags
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