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Microchip Technology AT28HC256E-70JI
- Part No.:
- AT28HC256E-70JI
- Manufacturer:
- Microchip Technology
- Category:
- Memory
- Package:
- 32-LCC (J-Lead)
- Datasheet:
-
AT28HC256E-70JI.pdf
- Description:
- IC EEPROM 256KBIT PAR 32PLCC
- Quantity:
- Payment:
- Shipping:
Inventory:1,838
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Product details
Overview
AT28HC256E-70JI 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 70 ns read access time, supports 64-byte page writes with ≤10 ms cycle time, and operates across –40°C to +85°C industrial temperature range on single 5V ±10% supply.
For engineers reviewing the AT28HC256E-70JI datasheet, AT28HC256E-70JI pinout, AT28HC256E-70JI application, or AT28HC256E-70JI equivalent, this page provides verified functional specifications, JEDEC-compliant byte-wide interface details, hardware/software write protection mechanisms, DATA polling and toggle-bit write completion detection, and industrial-grade reliability metrics including 100,000 write cycles and 10-year data retention.
Technical Context
The AT28HC256E-70JI implements a CMOS-based parallel EEPROM architecture with internal address/data latching for 64-byte page writes, automatic internal control timer for self-timed programming, and dual write-detection methods (DATA Polling on I/O7 and Toggle Bit on I/O6). Its JEDEC-approved 28-pin TSOP package enables direct replacement of SRAM in legacy memory interfaces without external timing logic.
Hardware write protection includes VCC sense (<3.8 V inhibits write), 5 ms power-on delay, noise filtering (<15 ns pulses rejected), and CE/OE/WE state enforcement. Software Data Protection (SDP) adds user-configurable 3-byte command sequence enable/disable for full-device or per-write-cycle security - shipped disabled, persistent across power cycles.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Memory Density | 256 Kbit (32,768 × 8), organized as byte-addressable parallel array |
| Read Access Time | 70 ns maximum - enables direct drop-in replacement for 70 ns SRAM in legacy bus designs |
| Page Write Cycle Time | ≤10 ms - supports burst loading of up to 64 bytes per internal programming operation |
| Endurance | 100,000 write/erase cycles - validated high-endurance variant (E-suffix) for frequent firmware update applications |
| Data Retention | 10 years at +85°C - guaranteed nonvolatile storage under continuous industrial operating conditions |
| Supply Voltage | 5V ±10% - compatible with standard TTL/CMOS logic families and legacy 5V system rails |
| Operating Temperature | –40°C to +85°C - qualified for industrial environments including factory automation and motor control |
Pinout & Package
AT28HC256E-70JI is packaged in a 28-lead Thin Small Outline Package (TSOP, Type I, 8 mm × 13.4 mm), compliant with JEDEC MO-183 and featuring gull-wing leads for surface-mount assembly. Pin 1 identifier is marked by a beveled corner.
| 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 | Bidirectional Data Bus | CMOS/TTL-compatible 8-bit data path; I/O7 used for DATA Polling, I/O6 for Toggle Bit status indication |
| CE | Chip Enable | Active-low chip select; must be low with OE low and WE high for read; initiates write when low with OE high |
| OE | Output Enable | Active-low output gate; controls data bus tristate during reads and write detection (must be high during page write) |
| WE | Write Enable | Active-low write strobe; falling edge latches address; rising edge latches data; used with CE for dual-control write initiation |
| VCC | Power Supply | +5V ±10% main supply; internal VCC sense circuitry disables writes below ~3.8V |
| GND | Ground Reference | Signal and power return; decoupling capacitor required within 10 mm of VCC/GND pins |
Key Features
| Feature | Design Value |
|---|---|
| 64-byte Page Write | Reduces firmware update time by up to 64× vs. byte-write; requires A6–A14 stable across all 64 bytes |
| DATA Polling (I/O7) | Enables real-time write completion detection without polling overhead or external timers |
| Toggle Bit (I/O6) | Provides asynchronous write status feedback independent of I/O7, supporting dual-method verification |
| Software Data Protection (SDP) | User-enabled 3-byte command sequence prevents accidental writes; remains active through power cycles |
| Hardware Write Inhibit | VCC sense, 5 ms power-on delay, and noise filtering eliminate spurious writes during brown-out or EMI events |
Applications
| Industrial PLC Firmware Storage | Medical Device Configuration Memory |
|---|---|
Use Scenario: Storing calibrated sensor coefficients and operational parameters in programmable logic controllers deployed in factory-floor environments with wide thermal swings and electrical noise. IC Role / Device Role / Timing Role: Nonvolatile configuration store accessed via parallel bus during boot and runtime reconfiguration; 70 ns read latency ensures deterministic scan-cycle timing. Use Value: 100,000-cycle endurance and 10-year retention guarantee field-upgradable firmware integrity over 15+ year product lifecycles without battery backup. | Use Scenario: Holding patient-specific therapy settings and calibration data in portable infusion pumps requiring FDA-compliant data persistence and tamper resistance. IC Role / Device Role / Timing Role: Secure parameter EEPROM interfaced to microcontroller via dedicated 8-bit bus; SDP prevents unintended overwrite during power transitions or software faults. Use Value: Hardware VCC sensing and software protection ensure zero unauthorized writes during power-up/down sequences critical for regulatory compliance. |
| Avionics Data Logger Buffer | Automotive Engine Control Module (ECM) |
Use Scenario: Capturing flight-critical telemetry snapshots in lightweight UAVs where weight, reliability, and radiation tolerance are prioritized over density. IC Role / Device Role / Timing Role: High-reliability parallel EEPROM used as circular buffer for pre-crash event data; accessed via discrete address/data lines without bus arbitration. Use Value: Industrial temperature range (–40°C to +85°C) and 100K-cycle endurance support repeated logging in thermally stressed airframe bays. | Use Scenario: Storing adaptive fuel trim tables and diagnostic trouble codes (DTCs) in engine control units exposed to under-hood thermal cycling and vibration. IC Role / Device Role / Timing Role: Directly mapped into MCU memory space as nonvolatile scratchpad; 70 ns access enables real-time DTC logging during misfire events. Use Value: Page-write capability reduces flash wear by minimizing erase cycles; 10-year retention meets OEM 15-year service life requirements. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar parallel EEPROM applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| AT28HC256-70JI | Standard endurance (10K cycles), 10 ms page write | Lower cost for infrequently updated systems | Select when firmware updates occur <100× lifetime and budget constraints dominate |
| AT28HC256F-70JI | Fast write option: 3 ms page write time, same 10K endurance | Reduced programming latency for high-throughput test equipment | Choose when production programming speed or rapid field updates are critical |
Compared with AT28HC256-70JI and AT28HC256F-70JI, the AT28HC256E-70JI uniquely balances long-term field reliability (100K cycles) with industrial temperature operation and full feature set - making it optimal for safety-critical or maintenance-sensitive deployments where endurance outweighs raw write speed.
Availability
AT28HC256E-70JI is available at Aetrix Electronics and suitable for industrial automation, medical device manufacturing, avionics data logging, and automotive ECM applications requiring stable component supply, long-term lifecycle assurance, and traceable sourcing.
Supply support for AT28HC256E-70JI 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 support for the AT28HC256 family, delivering high-reliability parallel EEPROMs for legacy and new-design integration.
The AT28HC256 product line was designed for direct SRAM replacement in 5V microcontroller systems requiring nonvolatile storage with zero external timing components - targeting industrial, medical, and aerospace applications demanding proven reliability and long-term availability.
FAQ
What is the endurance rating of the AT28HC256E-70JI?
The AT28HC256E-70JI is rated for 100,000 write/erase cycles - confirmed by Atmel's datasheet Section 27.1 and ordering code suffix "E", which designates the high-endurance variant. This exceeds the standard 10K-cycle version and supports frequent firmware or calibration updates in field-deployed equipment without premature wear-out. The AT28HC256E-70JI maintains this rating across its full industrial temperature range (–40°C to +85°C).
Does the AT28HC256E-70JI support both byte and page write operations?
Yes, the AT28HC256E-70JI supports both byte and page write modes. Byte writes require one WE pulse per byte; page writes allow 1–64 bytes to be loaded sequentially within 150 µs intervals, followed by a single internal programming cycle (≤10 ms). The A6–A14 address lines must remain constant during a page write to ensure all bytes reside on the same 64-byte page boundary - a requirement explicitly defined in Section 4.3 of the AT28HC256E-70JI datasheet.
How does DATA Polling work on the AT28HC256E-70JI?
During any write cycle (byte or page), reading the last written address returns the complement of the written data on I/O7 until programming completes. Once valid data appears on I/O7, the write is finished - enabling immediate subsequent access. This mechanism is electrically verified and requires no additional hardware; the AT28HC256E-70JI datasheet specifies that polling may begin at any point during tWC (Section 4.4). No external controller logic is needed.
Is the AT28HC256E-70JI pin-compatible with standard SRAM devices?
The AT28HC256E-70JI uses a JEDEC-approved byte-wide pinout identical to industry-standard 28-pin parallel SRAMs (e.g., 32K×8 SRAMs), supporting direct PCB replacement in existing designs. Its CE/OE/WE control scheme and timing parameters (70 ns tACC, 35 ns tOE) align with common SRAM interfaces. However, write timing differs: SRAM writes are instantaneous while AT28HC256E-70JI requires internal programming time - necessitating DATA Polling or Toggle Bit monitoring instead of simple address/data bus handshaking.
What package type is used for the AT28HC256E-70JI?
The AT28HC256E-70JI is supplied in a 28-lead Thin Small Outline Package (TSOP, Type I), measuring 8 mm × 13.4 mm, per JEDEC MO-183. This surface-mount package features gull-wing leads, a beveled corner for Pin 1 identification, and is optimized for automated assembly in high-density industrial PCBs. Package drawings and mechanical dimensions are documented in Section 31.7 of the AT28HC256E-70JI datasheet.
AT28HC256E-70JI 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:
- 70 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-70JI FAQ
1.How can I place an order for AT28HC256E-70JI through Aetrix?
Please submit a Request for Quotation (RFQ) for AT28HC256E-70JI 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-70JI reliable?
The price and inventory of AT28HC256E-70JI are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for AT28HC256E-70JI is usually 5 days.
3.What payment methods are accepted for AT28HC256E-70JI?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for AT28HC256E-70JI transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for AT28HC256E-70JI?
AT28HC256E-70JI orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your AT28HC256E-70JI 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-70JI?
For technical support, including AT28HC256E-70JI datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your AT28HC256E-70JI requirements.
6.How does Aetrix verify that AT28HC256E-70JI is sourced from the original manufacturer or authorized distributors?
All AT28HC256E-70JI 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-70JI meets industry standards.
7.What is the process for return or replacement of AT28HC256E-70JI?
All AT28HC256E-70JI units undergo pre-shipment inspection (PSI). If there is an issue with AT28HC256E-70JI, 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-70JI part is unused and in its original packaging.
Return procedure for AT28HC256E-70JI:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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