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Microchip Technology AT28HC256E-90JC
- Part No.:
- AT28HC256E-90JC
- Manufacturer:
- Microchip Technology
- Category:
- Memory
- Package:
- 32-LCC (J-Lead)
- Datasheet:
-
AT28HC256E-90JC.pdf
- Description:
- IC EEPROM 256KBIT PAR 32PLCC
- Quantity:
- Payment:
- Shipping:
Inventory:4,822
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Product details
Overview
AT28HC256E-90JC from Microchip Technology (formerly Atmel) is a 256 Kbit (32K × 8) parallel EEPROM IC designed for nonvolatile data storage in embedded systems requiring byte- and page-level reprogrammability. It delivers 90 ns read access time, supports 64-byte page writes with ≤10 ms cycle time, operates on single 5V ±10% supply, and guarantees 100,000 write cycles and 10-year data retention - used in industrial control firmware storage and configuration memory.
For engineers reviewing the AT28HC256E-90JC datasheet, AT28HC256E-90JC pinout, AT28HC256E-90JC application, or AT28HC256E-90JC equivalent, key selection considerations include JEDEC-standard 28-pin SOIC package compatibility, hardware/software write protection, DATA polling and toggle-bit write completion detection, and industrial temperature range (-40°C to +85°C) support.
Technical Context
The AT28HC256E-90JC implements a CMOS-based parallel EEPROM architecture with internal address/data latching for 64-byte page writes and an autonomous internal control timer. Its dual-line chip enable (CE) and output enable (OE) logic enables bus contention avoidance in SRAM-like read/write cycles without external timing components.
Write operation relies on either WE- or CE-controlled strobes with strict tBLC (≤150 µs) inter-byte timing for page mode; end-of-write detection is supported via I/O7 DATA polling or I/O6 toggle-bit behavior. Hardware protection includes VCC sense (<3.8 V inhibit), 5 ms power-on delay, and noise filtering on WE/CE inputs.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Memory Density | 256 Kbit (32,768 × 8), organized as byte-addressable parallel array |
| Read Access Time | 90 ns maximum - determines minimum CPU wait-state requirement for zero-wait-state interfacing |
| Page Write Cycle Time | ≤10 ms - defines worst-case latency for bulk 64-byte updates without host polling overhead |
| Endurance | 100,000 write/erase cycles - validated lifetime for high-frequency configuration logging |
| Data Retention | 10 years at +85°C - ensures long-term reliability in unpowered industrial environments |
| Supply Voltage | 5V ±10% - compatible with legacy 5V TTL/CMOS system rails without level-shifting |
| Operating Temperature | -40°C to +85°C - qualified for industrial-grade embedded applications |
Pinout & Package
AT28HC256E-90JC is supplied in a 28-lead plastic dual-inline package (PDIP), 0.600" wide (28P6), with JEDEC-standard byte-wide pinout and through-hole mounting.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| A0–A14 | Address Inputs | 15-bit address bus selecting one of 32,768 bytes; A6–A14 define page boundaries for 64-byte writes |
| I/O0–I/O7 | Bidirectional Data Bus | 8-bit parallel interface for read data output or write data input; supports true bidirectional SRAM-style access |
| CE | Chip Enable | Active-low global device select; must be low with OE low and WE high for valid read access |
| OE | Output Enable | Active-low output gate control; high during write cycles to place I/O pins in high-impedance state |
| WE | Write Enable | Active-low write strobe; falling edge latches address; rising edge latches data for byte/page programming |
| VCC, GND | Power Supply | Single 5V supply with decoupling required; ground reference for all digital and programming operations |
Key Features
| Feature | Design Value |
|---|---|
| 64-byte Page Write | Reduces firmware update time by up to 64× vs. byte writes; requires no external address sequencing logic |
| DATA Polling (I/O7) | Enables deterministic write completion detection without fixed delays - critical for real-time task scheduling |
| Toggle Bit (I/O6) | Provides asynchronous, non-intrusive write status monitoring - avoids bus contention during polling |
| Software Data Protection (SDP) | User-configurable 3-byte command sequence prevents accidental writes during power transitions or debug sessions |
| Hardware Write Inhibit | VCC sense, 5 ms power-on delay, and 15 ns noise filtering eliminate spurious writes in noisy or unstable supply conditions |
Applications
| Industrial PLC Configuration Storage | Medical Device Calibration Data |
|---|---|
Use Scenario: Storing user-modifiable I/O mapping tables and alarm thresholds in programmable logic controllers deployed in factory automation. IC Role / Device Role / Timing Role: Nonvolatile configuration memory accessed during boot and runtime via parallel bus; 90 ns read speed enables direct CPU read without wait states. Use Value: 100K endurance and 10-year retention ensure reliable operation across 15+ year equipment lifecycles without field recalibration. | Use Scenario: Holding factory-trimmed sensor calibration coefficients and safety-critical operational limits in portable diagnostic instruments. IC Role / Device Role / Timing Role: Secure, tamper-resistant parameter store with SDP enabled to prevent unauthorized modification during servicing. Use Value: Dual write-protection (hardware + software) meets IEC 62304 Class C software safety requirements for medical firmware integrity. |
| Avionics Maintenance Log Memory | Telecom Base Station Bootloader Storage |
Use Scenario: Recording flight-hour counters, fault logs, and maintenance timestamps in airborne control units operating across -55°C to +125°C (via extended temp variants). IC Role / Device Role / Timing Role: High-reliability EEPROM used in conjunction with microcontroller's bootloader to log events without DRAM backup. Use Value: Industrial-grade AT28HC256E-90JC variant provides guaranteed -40°C to +85°C operation and immunity to voltage droop during engine start transients. | Use Scenario: Storing field-upgradable bootloader images and secure boot keys in wireless infrastructure equipment requiring remote firmware recovery. IC Role / Device Role / Timing Role: Parallel-boot memory mapped into MCU address space; supports fast 90 ns reads for minimal boot latency. Use Value: Page write capability enables full 32 KB image updates in ≤10 ms, reducing service downtime during carrier-mandated security patches. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar parallel EEPROM applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| AT28C256-90JC | Standard endurance (10K cycles), 10 ms page write, same pinout and timing | Limited to infrequent configuration updates; not suitable for high-cycle logging | Select when cost sensitivity outweighs endurance requirements and write frequency is <100 cycles/year |
| MN5Q256A-90PL | Same 256 Kbit density and 90 ns access, but uses 32-lead PLCC package and lacks software data protection | Requires PCB redesign for PLCC footprint; no SDP feature increases risk of inadvertent writes | Choose only if PLCC is mandated by legacy board layout and hardware-only protection suffices |
Compared with AT28C256-90JC, the AT28HC256E-90JC offers 10× higher endurance and identical timing - ideal for dynamic configuration storage; versus MN5Q256A-90PL, it provides SDP and PDIP compatibility but requires no footprint change or additional security firmware.
Availability
AT28HC256E-90JC is available at Aetrix Electronics and suitable for industrial control systems, medical instrumentation, avionics maintenance recorders, and telecom base station bootloaders requiring stable component supply across extended product lifecycles.
Supply support for AT28HC256E-90JC 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 legacy AT28HC series, ensuring long-term availability, documentation, and qualification consistency for industrial and aerospace applications.
The AT28HC256E-90JC belongs to Atmel's high-endurance parallel EEPROM product line, engineered specifically for mission-critical firmware and configuration storage where data integrity, write-cycle longevity, and deterministic write completion are mandatory.
FAQ
What is the maximum page write size supported by the AT28HC256E-90JC?
The AT28HC256E-90JC supports a maximum page write size of 64 bytes per internal programming cycle. This is enabled by its internal 64-byte page register, which latches address and data automatically upon initiation of a write cycle. The A6–A14 address lines define the page boundary, and all bytes written within a single page write operation must reside on the same page. The AT28HC256E-90JC does not support larger block or sector writes beyond this 64-byte limit.
Does the AT28HC256E-90JC require a 12V programming voltage?
No, the AT28HC256E-90JC operates exclusively from a single 5V ±10% supply and does not require 12V for standard read, write, or page write operations. A 12V pulse on A9 is only required for accessing the optional 64-byte device identification memory (7FC0H–7FFFH), not for main array programming. All normal firmware and configuration writes use 5V only - simplifying power design and eliminating need for charge pumps or external HV generators.
How does software data protection (SDP) work on the AT28HC256E-90JC?
Software data protection (SDP) on the AT28HC256E-90JC is activated by writing a specific 3-byte sequence (0xAA → 0x55 → 0xA0) to addresses 0x5555, 0x2AAA, and 0x5555 respectively. Once enabled, all subsequent writes to the main memory array require repeating this sequence before each data byte or page. The AT28HC256E-90JC ships with SDP disabled, and the feature remains active across power cycles until explicitly disabled using the defined 5-byte disable sequence.
Can the AT28HC256E-90JC be used as a drop-in replacement for the AT28C256-90JC?
The AT28HC256E-90JC is pin-compatible and functionally compatible with the AT28C256-90JC, sharing identical pinout, timing specifications (90 ns access), and DC characteristics. However, it is not a drop-in replacement in applications requiring >10K write cycles, as the AT28HC256E-90JC provides 100K endurance while the AT28C256-90JC is rated for only 10K. No PCB changes are needed, but firmware must validate endurance requirements before substitution.
What package type is used for the AT28HC256E-90JC?
The AT28HC256E-90JC uses a 28-lead plastic dual-inline package (PDIP), 0.600" wide (ordering code suffix "JC"), compliant with JEDEC MS-011AB. This through-hole package features 0.100" lead pitch, 0.600" body width, and is RoHS-compliant with green (Pb/halide-free) construction. It is mechanically and electrically interchangeable with other 28P6-packaged variants of the AT28HC256 family.
AT28HC256E-90JC 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:
- 0°C ~ 70°C (TC)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 32-PLCC (13.97x11.43)
AT28HC256E-90JC FAQ
1.How can I place an order for AT28HC256E-90JC through Aetrix?
Please submit a Request for Quotation (RFQ) for AT28HC256E-90JC 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-90JC reliable?
The price and inventory of AT28HC256E-90JC are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for AT28HC256E-90JC is usually 5 days.
3.What payment methods are accepted for AT28HC256E-90JC?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for AT28HC256E-90JC transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for AT28HC256E-90JC?
AT28HC256E-90JC orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your AT28HC256E-90JC 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-90JC?
For technical support, including AT28HC256E-90JC datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your AT28HC256E-90JC requirements.
6.How does Aetrix verify that AT28HC256E-90JC is sourced from the original manufacturer or authorized distributors?
All AT28HC256E-90JC 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-90JC meets industry standards.
7.What is the process for return or replacement of AT28HC256E-90JC?
All AT28HC256E-90JC units undergo pre-shipment inspection (PSI). If there is an issue with AT28HC256E-90JC, 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-90JC part is unused and in its original packaging.
Return procedure for AT28HC256E-90JC:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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