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Microchip Technology AT28HC256E-90JI
- Part No.:
- AT28HC256E-90JI
- Manufacturer:
- Microchip Technology
- Category:
- Memory
- Package:
- 32-LCC (J-Lead)
- Datasheet:
-
AT28HC256E-90JI.pdf
- Description:
- IC EEPROM 256KBIT PAR 32PLCC
- Quantity:
- Payment:
- Shipping:
Inventory:3,695
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Product details
Overview
AT28HC256E-90JI from Microchip Technology (formerly Atmel) is a 256 Kbit (32K × 8) parallel EEPROM IC designed for nonvolatile data storage in embedded control and instrumentation systems. It delivers 90 ns read access time, supports 1–64-byte page writes with ≤10 ms write cycle time, and operates across –40°C to +85°C industrial temperature range on single 5V ±10% supply.
For engineers reviewing the AT28HC256E-90JI datasheet, AT28HC256E-90JI pinout, AT28HC256E-90JI application, or AT28HC256E-90JI equivalent, key selection considerations include its JEDEC-standard byte-wide parallel interface, hardware/software write protection, DATA polling and toggle-bit write completion detection, and high endurance (100,000 cycles) enabled by the 'E' suffix variant.
Technical Context
The AT28HC256E-90JI implements a CMOS-based parallel EEPROM architecture with internal address/data latching for page write operations and an integrated control timer that autonomously manages programming timing. Its dual-line chip enable (CE) and output enable (OE) control enables bus contention avoidance in multi-device systems.
Write operation support includes byte-write, 64-byte page-write, software-controlled chip erase, and optional software data protection (SDP) via three-byte unlock sequences. End-of-write detection is implemented via I/O7 DATA polling and I/O6 toggle-bit mechanisms - both usable at any point during the write cycle.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Memory Size | 256 Kbit (32,768 × 8), organized as byte-addressable parallel array |
| Read Access Time | 90 ns maximum - ensures compatibility with 11 MHz bus timing in legacy microcontroller systems |
| Page Write Cycle Time | ≤10 ms - enables efficient bulk updates without external timing circuitry |
| Endurance | 100,000 write/erase cycles - specified for 'E' variant, enabling long-term field logging applications |
| Data Retention | 10 years at 85°C - validated for industrial environments with elevated thermal stress |
| Supply Voltage | 5 V ±10% - compatible with standard TTL/CMOS logic rails and legacy power domains |
| Operating Temperature | –40°C to +85°C - qualified for industrial-grade reliability per ordering code 'JI' |
Pinout & Package
AT28HC256E-90JI is supplied in a 28-lead Plastic Dual Inline Package (PDIP), 0.600" wide (package code 'JI' per Microchip ordering guide), with JEDEC-standard byte-wide pinout and no internal connections on pins 1 and 17 in PLCC variants (not applicable here).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| A0–A14 | Address Inputs | 15-bit address bus selecting one of 32,768 memory locations |
| I/O0–I/O7 | Bidirectional Data Bus | 8-bit parallel interface supporting read, byte-write, and page-write transfers |
| 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 control; used with CE to prevent bus contention |
| WE | Write Enable | Active-low write strobe; falling edge latches address/data for byte or page write |
| VCC | Power Supply | +5 V ±10% main supply; powers core logic and memory array |
| GND | Ground Reference | Signal and power return path; decoupling required near VCC pin |
Key Features
| Feature | Design Value |
|---|---|
| Hardware Write Protection | VCC sense (inhibit below 3.8 V), 5 ms power-on delay, and noise filtering (<15 ns pulses rejected) |
| Software Data Protection (SDP) | User-configurable lock/unlock via 3-byte command sequence; persists through power cycles |
| Page Write Capability | Up to 64 bytes written in one internal cycle - reduces host CPU overhead vs. sequential byte writes |
| Write Completion Detection | Dual-mode: I/O7 DATA polling (complement → true data) and I/O6 toggle-bit (stop toggling on completion) |
| Extended Device Identification | 64-byte dedicated EEPROM section (7FC0H–7FFFH) accessible via A9 = 12 V for traceability or calibration data |
Applications
| Industrial PLC Data Logging | Medical Instrument Calibration Storage |
|---|---|
Use Scenario: Storing sensor calibration coefficients and operational history in programmable logic controllers deployed in factory automation. IC Role / Device Role / Timing Role: Nonvolatile parallel EEPROM providing direct-mapped, byte-accessible storage with deterministic 90 ns read latency. Use Value: Enables field-updatable calibration without firmware changes; 100,000-cycle endurance supports >10 years of daily recalibration events. | Use Scenario: Retaining patient-specific configuration and transducer calibration data in portable diagnostic devices. IC Role / Device Role / Timing Role: Secure, low-power nonvolatile memory with hardware/software write protection to prevent accidental overwrites during battery-powered operation. Use Value: Ensures regulatory compliance via tamper-resistant storage; 10-year data retention meets IEC 62304 requirements for Class II medical devices. |
| Avionics Control Module Configuration | Telecom Base Station Boot Parameters |
Use Scenario: Holding flight-critical configuration tables and fault history in airborne control units operating across –40°C to +85°C. IC Role / Device Role / Timing Role: Industrial-temperature-rated parallel EEPROM interfaced directly to MIL-STD-1553 or ARINC 429 controller buses. Use Value: Eliminates need for external level-shifting or timing glue logic; JEDEC pinout ensures drop-in compatibility with legacy avionics designs. | Use Scenario: Storing boot-time FPGA configuration bitstreams and RF tuning parameters in outdoor telecom infrastructure. IC Role / Device Role / Timing Role: High-reliability parallel EEPROM accessed during cold start prior to main processor initialization. Use Value: Fast 90 ns read access accelerates system boot; page-write capability allows rapid parameter updates during remote maintenance windows. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar parallel EEPROM applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| AT28HC256-90JI | Standard endurance (10,000 cycles); same package, speed, and temperature rating | Lacks extended write-cycle lifetime; suitable for infrequent update scenarios | Select when cost sensitivity outweighs long-term field update requirements |
| AT28HC256F-90JI | Faster write cycle (3 ms max vs. 10 ms); identical endurance and interface | Reduces host wait time during firmware patching or parameter uploads | Prefer for real-time systems requiring sub-5 ms write latency guarantees |
Compared with AT28HC256-90JI and AT28HC256F-90JI, the AT28HC256E-90JI uniquely balances high endurance (100K cycles) with industrial temperature operation and standard 10 ms write timing - making it optimal for applications where data integrity over decades matters more than write speed.
Availability
AT28HC256E-90JI is available at Aetrix Electronics and suitable for industrial PLC data logging, medical instrument calibration storage, and avionics control module configuration requiring stable component supply and long-term lifecycle support.
Supply support for AT28HC256E-90JI 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 robust, pin-compatible replacement of EPROM and early Flash in legacy parallel-bus embedded systems - emphasizing reliability, wide temperature operation, and simplified system integration without external timing components.
FAQ
What is the endurance rating of the AT28HC256E-90JI?
The AT28HC256E-90JI is rated for 100,000 write/erase cycles - a specification confirmed by Microchip's datasheet for the 'E' (High Endurance) variant. This exceeds the base AT28HC256 (10,000 cycles) and supports applications requiring frequent field updates, such as industrial data loggers or medical device calibration storage. The rating applies across the full –40°C to +85°C operating range.
Does the AT28HC256E-90JI support page write operations, and what is the maximum page size?
Yes, the AT28HC256E-90JI supports page write operations with a maximum size of 64 bytes per internal programming cycle. The device uses an internal 64-byte page register to latch address and data; successive bytes must be loaded within 150 µs of each other, and all addresses must reside on the same page (A6–A14 unchanged). This capability significantly reduces host processor overhead compared to individual byte writes.
How is write completion detected on the AT28HC256E-90JI?
The AT28HC256E-90JI provides two hardware-supported methods: DATA polling on I/O7 (returns complement of last written byte until completion, then true data) and toggle-bit detection on I/O6 (toggles between 0 and 1 during write, stops toggling upon completion). Both methods are usable at any time during the write cycle and require no additional timing components - enabling reliable, software-driven write synchronization.
What package type is used for the AT28HC256E-90JI?
The AT28HC256E-90JI uses a 28-lead Plastic Dual Inline Package (PDIP), 0.600" wide (ordering code 'JI'), with JEDEC-standard byte-wide pinout. This through-hole package supports industrial temperature operation (–40°C to +85°C) and is compatible with legacy PCB layouts designed for similar parallel EEPROMs like the AT28C256. Pin 1 is marked with a notch or dot per JEDEC MS-011 AB.
Is software data protection (SDP) enabled by default on the AT28HC256E-90JI?
No, software data protection (SDP) is disabled by default on the AT28HC256E-90JI. It can be enabled or disabled using documented three-byte command sequences written to specific addresses (e.g., 5555H, 2AAAH, 5555H). Once enabled, SDP remains active across power cycles and requires the same unlock sequence before any write operation - preventing inadvertent writes during power transitions or system resets.
AT28HC256E-90JI 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:
- 90 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-90JI FAQ
1.How can I place an order for AT28HC256E-90JI through Aetrix?
Please submit a Request for Quotation (RFQ) for AT28HC256E-90JI 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-90JI reliable?
The price and inventory of AT28HC256E-90JI are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for AT28HC256E-90JI is usually 5 days.
3.What payment methods are accepted for AT28HC256E-90JI?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for AT28HC256E-90JI transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for AT28HC256E-90JI?
AT28HC256E-90JI orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your AT28HC256E-90JI 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-90JI?
For technical support, including AT28HC256E-90JI datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your AT28HC256E-90JI requirements.
6.How does Aetrix verify that AT28HC256E-90JI is sourced from the original manufacturer or authorized distributors?
All AT28HC256E-90JI 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-90JI meets industry standards.
7.What is the process for return or replacement of AT28HC256E-90JI?
All AT28HC256E-90JI units undergo pre-shipment inspection (PSI). If there is an issue with AT28HC256E-90JI, 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-90JI part is unused and in its original packaging.
Return procedure for AT28HC256E-90JI:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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