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Microchip Technology AT28HC256-90JU-600
- Part No.:
- AT28HC256-90JU-600
- Manufacturer:
- Microchip Technology
- Category:
- Memory
- Package:
- 32-LCC (J-Lead)
- Datasheet:
-
AT28HC256-90JU-600.pdf
- Description:
- IC EEPROM 256KBIT PAR 32PLCC
- Quantity:
- Payment:
- Shipping:
Inventory:3,513
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Product details
Overview
AT28HC256-90JU-600 from Microchip Technology is a 256-Kbit (32,768 × 8) parallel EEPROM with 90 ns read access time, single 5V ±10% supply, JEDEC-standard byte-wide pinout, and industrial temperature range (–40°C to +85°C). It supports automatic 1–64-byte page writes with internal latching and data polling for write completion detection, used in firmware storage and configuration retention for embedded controllers.
For engineers reviewing the AT28HC256-90JU-600 datasheet, AT28HC256-90JU-600 pinout, AT28HC256-90JU-600 application, or AT28HC256-90JU-600 equivalent, key selection factors include its 90 ns read timing, 3 mA standby current, hardware/software write protection, 10,000-cycle endurance, and PLCC-32 packaging compatibility with legacy 8-bit bus systems.
Technical Context
The AT28HC256-90JU-600 implements a CMOS-based parallel EEPROM architecture with dual-line control (CE/OE) for bus contention avoidance and supports three primary operations: byte write, page write (up to 64 bytes), and chip erase via 12V programming. Its internal address/data latches decouple bus activity during write cycles.
Write completion is verified using either DATA Polling (I/O7 complement toggle) or Toggle Bit (I/O6 state alternation), both usable at any point during tWC. 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 Size | 256 Kbit (32,768 × 8) - supports full 16-bit address space with byte-level random access |
| Read Access Time | 90 ns - meets timing requirements for 11 MHz CPU bus interfaces without wait states |
| Page Write Cycle | ≤10 ms - enables efficient bulk configuration updates without host-side timeout management |
| Endurance | 10,000 write/erase cycles - sufficient for field-updatable calibration tables and infrequent parameter storage |
| Standby Current | 3 mA - reduces system power in sleep modes while retaining nonvolatile memory state |
| Supply Voltage | 5V ±10% - compatible with standard TTL/CMOS logic rails and eliminates need for auxiliary regulators |
| Data Retention | 10 years - ensures long-term reliability in unpowered industrial deployments |
Pinout & Package
AT28HC256-90JU-600 uses a 32-lead Plastic Leaded Chip Carrier (PLCC) package with gull-wing leads, RoHS-compliant green molding compound, and JEDEC-standard byte-wide pinout. Pin 1 and Pin 17 are designated "Don't Connect" per datasheet.
| 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 page writes |
| I/O0–I/O7 | Bidirectional Data Bus | 8-bit parallel interface compatible with 8051, Z80, and 68K family microcontrollers; I/O7 used for DATA Polling, I/O6 for Toggle Bit |
| CE | Chip Enable | Active-low device select; must be low with OE low and WE high for read; initiates write when pulsed low with OE high |
| OE | Output Enable | Active-low output control; enables tri-state output drivers during read; high during write to prevent bus contention |
| WE | Write Enable | Active-low write strobe; falling edge latches address and data; used with CE for flexible write initiation |
| VCC / GND | Power Supply | Single 5V supply with dedicated ground; decoupling required within 1 cm of pins 32 and 16 per layout guidelines |
| DC (Pins 1, 17) | Don't Connect | No internal connection; must remain unconnected to avoid signal integrity or thermal issues |
| NC (Pins 12, 26) | No Connect | Unbonded die pads; electrically isolated and should not be routed or tied |
Key Features
| Feature | Design Value |
|---|---|
| Automatic Page Write | Internal 64-byte latch and timer eliminate host software overhead for multi-byte writes and free address/data bus during programming |
| DATA Polling & Toggle Bit | Dual asynchronous write-complete detection methods allow real-time status monitoring without fixed delays or external timers |
| Hardware Write Protection | VCC sense, 5 ms power-on delay, and 15 ns noise filtering prevent spurious writes during brown-out or EMI events |
| Software Data Protection | User-configurable SDP lock/unlock sequence prevents accidental overwrites while permitting intentional updates via command protocol |
| Device Identification Area | 64-byte reserved EEPROM region (7FC0H–7FFFH) accessible at 12V for unique serialization or calibration data storage |
Applications
| Industrial PLC Configuration Storage | Medical Device Calibration Tables |
|---|---|
Use Scenario: Storing I/O mapping, PID tuning parameters, and alarm thresholds in programmable logic controllers deployed in factory automation environments. IC Role / Device Role / Timing Role: Nonvolatile configuration register providing byte-addressable, field-updatable memory with 90 ns read access for real-time control loop initialization. Use Value: Enables zero-downtime parameter updates via serial interface and guarantees data persistence across 10+ year equipment lifecycles without battery backup. | Use Scenario: Retaining sensor calibration coefficients, patient history flags, and regulatory compliance logs in portable diagnostic instruments. IC Role / Device Role / Timing Role: Secure, tamper-resistant memory block accessed during boot and runtime to validate sensor accuracy and audit trail integrity. Use Value: Meets IEC 62304 Class C software requirements via hardware/software write protection and 10,000-cycle endurance for recalibration events. |
| Automotive Body Control Module (BCM) | Legacy Industrial HMI Firmware |
Use Scenario: Holding seat position presets, mirror angle settings, and lighting profiles in automotive BCMs operating across –40°C to +85°C ambient. IC Role / Device Role / Timing Role: Automotive-grade EEPROM interfacing directly to 8-bit MCU parallel bus for fast, deterministic configuration recall at power-on. Use Value: Delivers guaranteed 10-year data retention and immunity to voltage transients via VCC-sense write inhibition during ignition cycling. | Use Scenario: Hosting boot firmware and UI assets in panel-mounted HMIs based on aging 80C51 or 68HC11 platforms with no flash upgrade path. IC Role / Device Role / Timing Role: Drop-in replacement for obsolete EPROM sockets, providing in-system reprogrammability without board redesign. Use Value: Eliminates UV erasers and socket programmers; supports field firmware patches via existing parallel bus infrastructure. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar parallel EEPROM applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| AT28HC256-90PU | Same die, 28-pin SOIC package; no DC/NC pins; smaller footprint but lower thermal mass | Limited to PCBs with SOIC land patterns; unsuitable for PLCC sockets or high-vibration environments | Select when board space is constrained and mechanical robustness is secondary to density |
| MX28F256KX | 256 Kbit Flash (not EEPROM); requires sector erase; no byte-write capability; 120 ns read | Requires full-sector erase before rewrite; incompatible with byte-level update workflows | Choose only if migrating to flash architecture and accepting erase/write latency penalties |
Compared with AT28HC256-90PU, the AT28HC256-90JU-600 offers superior mechanical stability and socket compatibility; versus MX28F256KX, it provides true byte-erasable operation and deterministic 90 ns reads essential for real-time configuration access.
Availability
AT28HC256-90JU-600 is available at Aetrix Electronics and suitable for industrial PLCs, medical diagnostics equipment, automotive body control modules, and legacy HMI systems requiring stable component supply, long-lifecycle support, and RoHS-compliant green packaging.
Supply support for AT28HC256-90JU-600 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 Inc. is a global semiconductor company specializing in microcontrollers, analog devices, and nonvolatile memory solutions, with design centers and manufacturing facilities across the Americas, Europe, and Asia.
The AT28HC256 product line delivers high-reliability parallel EEPROMs optimized for industrial, automotive, and medical applications where deterministic timing, long data retention, and robust write protection are critical.
FAQ
What is the maximum page write size supported by the AT28HC256-90JU-600?
The AT28HC256-90JU-600 supports up to 64 bytes per page write operation. All bytes must reside on the same page, defined by address bits A6–A14. Each successive byte must be loaded within 150 µs of the prior one; exceeding this interval triggers internal programming. This capability enables efficient bulk updates without host CPU intervention during the write cycle.
Does the AT28HC256-90JU-600 require a 12V supply for normal operation?
No, the AT28HC256-90JU-600 operates from a single 5V ±10% supply during read and standard write operations. A 12V ±0.5V supply is required only for optional chip erase mode or writing to the 64-byte device identification area (7FC0H–7FFFH). Normal firmware and configuration storage uses only 5V, simplifying power design.
How does hardware write protection function in the AT28HC256-90JU-600?
Hardware write protection in the AT28HC256-90JU-600 includes VCC sensing (write inhibited below ~3.8 V), a 5 ms internal power-on delay after VCC stabilization, and noise filtering rejecting pulses <15 ns on WE/CE. These features prevent unintended writes during power-up, brown-out, or EMI events-critical for industrial and automotive deployments where supply instability is common.
Can the AT28HC256-90JU-600 be used as a direct replacement for older AT28C256 variants?
Yes, the AT28HC256-90JU-600 is pin-compatible and functionally equivalent to AT28C256 in 32-lead PLCC packages, with identical JEDEC byte-wide pinout and timing. It improves upon AT28C256 with faster 90 ns access, lower 3 mA standby current, and enhanced hardware/software protection-requiring no PCB changes for drop-in replacement in legacy designs.
What is the purpose of the DATA Polling feature in the AT28HC256-90JU-600?
DATA Polling in the AT28HC256-90JU-600 allows real-time detection of write completion by reading the last written byte: I/O7 returns the complement of the data during programming and reverts to true data upon completion. This eliminates fixed delay loops, enabling optimal host CPU utilization and deterministic timing in time-critical embedded systems.
AT28HC256-90JU-600 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Microchip Technology
- Series:
- -
- Package/Case:
- 32-LCC (J-Lead)
- 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:
- 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)
AT28HC256-90JU-600 FAQ
1.How can I place an order for AT28HC256-90JU-600 through Aetrix?
Please submit a Request for Quotation (RFQ) for AT28HC256-90JU-600 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 AT28HC256-90JU-600 reliable?
The price and inventory of AT28HC256-90JU-600 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for AT28HC256-90JU-600 is usually 5 days.
3.What payment methods are accepted for AT28HC256-90JU-600?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for AT28HC256-90JU-600 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for AT28HC256-90JU-600?
AT28HC256-90JU-600 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your AT28HC256-90JU-600 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 AT28HC256-90JU-600?
For technical support, including AT28HC256-90JU-600 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your AT28HC256-90JU-600 requirements.
6.How does Aetrix verify that AT28HC256-90JU-600 is sourced from the original manufacturer or authorized distributors?
All AT28HC256-90JU-600 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 AT28HC256-90JU-600 meets industry standards.
7.What is the process for return or replacement of AT28HC256-90JU-600?
All AT28HC256-90JU-600 units undergo pre-shipment inspection (PSI). If there is an issue with AT28HC256-90JU-600, 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 AT28HC256-90JU-600 part is unused and in its original packaging.
Return procedure for AT28HC256-90JU-600:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
AT28HC256-90JU-600 Tags
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