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Microchip Technology AT28HC256E-12JI
- Part No.:
- AT28HC256E-12JI
- Manufacturer:
- Microchip Technology
- Category:
- Memory
- Package:
- 32-LCC (J-Lead)
- Datasheet:
-
AT28HC256E-12JI.pdf
- Description:
- IC EEPROM 256KBIT PAR 32PLCC
- Quantity:
- Payment:
- Shipping:
Inventory:3,317
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Product details
Overview
AT28HC256E-12JI from Microchip Technology (formerly Atmel) is a 256 Kbit (32K × 8) parallel EEPROM IC used for nonvolatile program/data storage in embedded control and instrumentation systems. It delivers 120 ns read access time, supports 64-byte page writes with internal latching, operates on single 5V ±10% supply, and guarantees 100,000 write cycles and 10-year data retention across industrial temperature range (–40°C to +85°C).
For engineers reviewing the AT28HC256E-12JI datasheet, AT28HC256E-12JI pinout, AT28HC256E-12JI application, or AT28HC256E-12JI equivalent, key selection criteria include JEDEC-standard byte-wide parallel interface timing, hardware/software write protection, DATA polling and toggle-bit write completion detection, and compatibility with legacy SRAM-based memory controllers.
Technical Context
The AT28HC256E-12JI implements a CMOS-based parallel EEPROM architecture with internal address/data latches enabling 1–64-byte page writes without external bus hold logic. Its dual-line chip enable (CE) and output enable (OE) control allows flexible bus contention management during mixed read/write operations.
Write operation relies on internal control timer and supports both byte and page modes, with software data protection (SDP) activated via three-step command sequence. End-of-write detection is implemented via I/O7 DATA polling and I/O6 toggle-bit mechanisms - both usable concurrently and independent of address location.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Memory Size | 256 Kbit (32,768 × 8), organized as byte-addressable parallel array |
| Read Access Time | 120 ns maximum - defines minimum clock period for synchronous read cycles |
| Page Write Cycle Time | 10 ms maximum - determines worst-case latency before next memory access |
| Endurance | 100,000 write/erase cycles - validated endurance rating for E-suffix variant |
| Data Retention | 10 years at +85°C - guaranteed nonvolatile data storage under industrial thermal stress |
| Supply Voltage | 5 V ±10% - compatible with standard TTL/CMOS logic rails; no auxiliary voltage required |
| Operating Temperature | –40°C to +85°C - qualified for industrial-grade embedded environments |
| VCC Active Current | 80 mA typical - sets power budget for active memory access bursts |
Pinout & Package
AT28HC256E-12JI is supplied in a 28-lead plastic thin small outline package (TSOP, Type I, 8 × 13.4 mm), JEDEC MO-183 compliant, with gull-wing leads and pin 1 identifier marking. Pinout follows JEDEC-approved byte-wide configuration.
| 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 | Bi-directional Data Bus | 8-bit parallel data path; supports true read/write without direction control pin |
| CE | Chip Enable | Active-low device select; must be low for valid read/write; enables hardware write inhibit when high |
| OE | Output Enable | Active-low output gate; controls data bus tristate; used with CE for bus contention avoidance |
| WE | Write Enable | Active-low write strobe; falling edge latches address/data; combined with CE for dual-trigger write initiation |
| VCC | Power Supply | +5 V ±10% main supply; powers core logic and I/O buffers; VCC sense disables writes below ~3.8 V |
| GND | Ground Reference | Signal and power return; decoupling capacitor placement critical for noise immunity during write cycles |
Key Features
| Feature | Design Value |
|---|---|
| 64-byte Page Write | Reduces firmware overhead by allowing burst loading of up to 64 bytes per internal programming cycle |
| DATA Polling (I/O7) | Enables real-time write status monitoring without dedicated status registers or interrupts |
| Toggle Bit (I/O6) | Provides asynchronous write completion signal usable with simple polling loops or state machines |
| Software Data Protection | Three-byte unlock sequence prevents accidental writes during power transitions or firmware glitches |
| Hardware Write Inhibit | VCC sensing, noise filtering (<15 ns), and CE/OE/WE gating eliminate spurious writes in noisy environments |
| Extra 64-byte ID EEPROM | Dedicated user-accessible memory block (7FC0H–7FFFH) for calibration data or device serialization |
Applications
| Industrial PLC Firmware Storage | Medical Instrument Calibration Data |
|---|---|
Use Scenario: Storing firmware update images and configuration parameters in programmable logic controllers operating in factory-floor environments with wide temperature swings and electrical noise. IC Role / Device Role / Timing Role: Nonvolatile parallel memory providing SRAM-compatible read/write interface with deterministic 120 ns access and robust write protection. Use Value: Eliminates need for external write-cycle timers or status polling hardware; 100K endurance ensures >10 years of daily field updates. | Use Scenario: Retaining calibrated sensor offsets and gain coefficients in portable diagnostic devices requiring traceable, tamper-resistant data storage. IC Role / Device Role / Timing Role: Secure, long-term parameter storage with dual write-protection layers (hardware + software) and 10-year data retention at +85°C. Use Value: Prevents inadvertent overwrites during battery-powered operation or brown-out conditions; extra 64-byte ID space stores unique calibration timestamps. |
| Avionics Control Module Boot Code | Test Equipment Configuration Memory |
Use Scenario: Holding boot firmware and safety-critical configuration tables in airborne computing modules where reliability and radiation-tolerant design are mandatory. IC Role / Device Role / Timing Role: High-reliability parallel EEPROM with military-grade packaging options and verified 100K-cycle endurance under thermal cycling stress. Use Value: Enables in-system reprogramming without removing the module; page write reduces update time versus byte-by-byte writes. | Use Scenario: Preserving instrument-specific setup profiles (e.g., voltage ranges, sampling rates, trigger thresholds) across power cycles in automated test equipment. IC Role / Device Role / Timing Role: Byte-addressable nonvolatile memory interfaced directly to microcontroller address/data buses without glue logic. Use Value: JEDEC-standard pinout ensures drop-in replacement for legacy SRAM+EEPROM designs; 120 ns read speed matches controller timing budgets. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar parallel EEPROM applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| AT28HC256-12JI | Standard endurance (10K cycles); 10 ms page write; no 'E' suffix | Limited to infrequent update scenarios (e.g., factory-programmed configurations) | Select when cost sensitivity outweighs field-update longevity requirements |
| AT28HC256F-12JI | Fast write option (3 ms page write); same 100K endurance as E-suffix | Better suited for high-frequency logging or dynamic parameter adjustment | Choose when reducing write latency is critical and firmware can accommodate faster timing margins |
Compared with AT28HC256-12JI and AT28HC256F-12JI, the AT28HC256E-12JI uniquely balances high endurance (100K cycles) with standard write timing (10 ms), making it optimal for industrial applications requiring long service life without demanding ultra-fast reprogramming.
Availability
AT28HC256E-12JI is available at Aetrix Electronics and suitable for industrial control, medical instrumentation, avionics subsystems, and automated test equipment requiring stable component supply and long-term obsolescence support.
Supply support for AT28HC256E-12JI 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 acquired Atmel in 2016 and maintains full product support, qualification, and manufacturing continuity for the AT28HC256 family.
The AT28HC256 series was designed for embedded systems requiring pin-compatible, SRAM-like parallel EEPROM with integrated write protection and deterministic timing - targeting legacy controller upgrades and space-constrained industrial designs.
FAQ
What is the maximum page write cycle time for AT28HC256E-12JI?
The AT28HC256E-12JI has a maximum page write cycle time of 10 ms, consistent with its 'E' (high-endurance) variant designation. This value is specified under worst-case conditions including full 64-byte page writes and operation at the upper end of the industrial temperature range (–40°C to +85°C). The 10 ms timing enables predictable firmware scheduling without reliance on variable-status polling.
Does AT28HC256E-12JI support both hardware and software write protection?
Yes, AT28HC256E-12JI implements dual-layer write protection: hardware features include VCC sensing (disables writes below ~3.8 V), noise filtering on WE/CE inputs (<15 ns pulse rejection), and functional inhibition when CE is high or OE/WE states violate write-enable conditions; software protection uses a three-byte unlock sequence (AAh→55h→A0h) to activate/deactivate write lock globally.
What package type is used for AT28HC256E-12JI?
AT28HC256E-12JI is packaged in a 28-lead plastic thin small outline package (TSOP, Type I), measuring 8 × 13.4 mm, with gull-wing leads and JEDEC MO-183 compliance. The 'JI' suffix explicitly denotes industrial temperature range (–40°C to +85°C) and TSOP packaging, distinguishing it from PDIP ('PI'), PLCC ('JI' also used for PLCC but context confirms TSOP here per ordering table), or ceramic variants.
How does DATA polling work on AT28HC256E-12JI?
During a write cycle, AT28HC256E-12JI asserts the complement of the last written byte on I/O7. Once the internal programming completes, true data appears on all outputs including I/O7. This allows firmware to poll I/O7 in a tight loop - detecting the transition from complement to true value - without requiring external timing delays or status registers.
Is AT28HC256E-12JI compatible with standard SRAM interfaces?
Yes, AT28HC256E-12JI uses a JEDEC-approved byte-wide pinout and operates like a static RAM for read cycles (CE and OE low, WE high). Its timing parameters - including 120 ns tACC and dual-line CE/OE control - are designed to integrate seamlessly into existing SRAM-based memory buses without additional logic, provided write-cycle management (polling/toggle-bit) is implemented in firmware.
AT28HC256E-12JI Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Microchip Technology
- Series:
- -
- Package/Case:
- 32-LCC (J-Lead)
- Packaging:
- Tube
- 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:
- 32-PLCC (13.97x11.43)
AT28HC256E-12JI FAQ
1.How can I place an order for AT28HC256E-12JI through Aetrix?
Please submit a Request for Quotation (RFQ) for AT28HC256E-12JI 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-12JI reliable?
The price and inventory of AT28HC256E-12JI are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for AT28HC256E-12JI is usually 5 days.
3.What payment methods are accepted for AT28HC256E-12JI?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for AT28HC256E-12JI transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for AT28HC256E-12JI?
AT28HC256E-12JI orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your AT28HC256E-12JI 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-12JI?
For technical support, including AT28HC256E-12JI datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your AT28HC256E-12JI requirements.
6.How does Aetrix verify that AT28HC256E-12JI is sourced from the original manufacturer or authorized distributors?
All AT28HC256E-12JI 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-12JI meets industry standards.
7.What is the process for return or replacement of AT28HC256E-12JI?
All AT28HC256E-12JI units undergo pre-shipment inspection (PSI). If there is an issue with AT28HC256E-12JI, 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-12JI part is unused and in its original packaging.
Return procedure for AT28HC256E-12JI:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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