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Microchip Technology AT28C256EF-15JU
- Part No.:
- AT28C256EF-15JU
- Manufacturer:
- Microchip Technology
- Category:
- Memory
- Package:
- 32-LCC (J-Lead)
- Datasheet:
-
AT28C256EF-15JU.pdf
- Description:
- IC EEPROM 256KBIT PAR 32PLCC
- Quantity:
- Payment:
- Shipping:
Inventory:4,388
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Product details
Overview
AT28C256EF-15JU from Microchip Technology is an industrial-grade 256-Kbit paged parallel EEPROM organized as 32,768 × 8, featuring 150 ns read access time, 3 ms maximum page write cycle time, and single 5V ±10% supply operation. It supports hardware/software data protection, DATA polling, and toggle-bit write completion detection for embedded control and firmware storage applications.
For engineers reviewing the AT28C256EF-15JU datasheet, AT28C256EF-15JU pinout, AT28C256EF-15JU application, or AT28C256EF-15JU equivalent, key selection considerations include JEDEC byte-wide pin compatibility, 64-byte page write capability, 100,000 write endurance, industrial temperature range (–40°C to +85°C), and PLCC-32 packaging with DC/NC pins requiring open-circuit handling.
Technical Context
The AT28C256EF-15JU implements a paged write architecture with internal 64-byte latches and autonomous control timer, enabling up to 64-byte writes within a single 3 ms programming cycle. Its dual-line chip enable (CE) and output enable (OE) logic allows bus contention avoidance in shared-memory systems.
It integrates VCC sense (write inhibit below 3.8 V), 5 ms power-on delay, noise filtering (<15 ns pulse rejection), and software data protection (SDP) with three-byte unlock sequences. The device includes 64 bytes of dedicated identification memory accessible via A9 = 12 V and addresses 7FC0H–7FFFH.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Memory Density | 256 Kbit (32,768 × 8) - supports full firmware image or configuration table storage without external address multiplexing |
| Read Access Time | 150 ns - enables direct interface with 5–6 MHz microcontrollers without wait states |
| Page Write Cycle Time | 3 ms max - reduces firmware update latency vs. byte-write-only EEPROMs |
| Write Endurance | 100,000 cycles - suitable for field-upgradable systems requiring frequent parameter logging |
| Operating Voltage | 5 V ±10% - compatible with legacy 5 V logic families and mixed-voltage system rails |
| Temperature Range | –40°C to +85°C - qualified for industrial control, automotive body electronics, and outdoor equipment |
| Standby Current | 200 µA CMOS - enables low-power sleep modes in battery-backed applications |
Pinout & Package
AT28C256EF-15JU is supplied in a 32-lead Plastic Leaded Chip Carrier (PLCC) package per JEDEC MS-016 Variation AE, with lead pitch 1.27 mm, body size 12.4–12.6 mm × 14.9–15.1 mm, and coplanarity ≤0.102 mm. Two pins (DC at position 1 and DC at position 17) are designated "Don't Connect" and must remain unconnected.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| DC (1, 17) | No-connect terminal | Internally unconnected; must be left floating-no PCB trace or pull-up/down allowed |
| A0–A14 | Address inputs | 15-bit address bus supporting full 32K-word addressing; A6–A14 define 64-byte page boundaries |
| 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 |
| CE | Chip Enable | Active-low chip select; required low with OE low and WE high for read access |
| OE | Output Enable | Active-low output gate; controls tri-state buffer-critical for bus arbitration in multi-device systems |
| WE | Write Enable | Active-low write strobe; falling edge latches address/data during byte or page write |
| VCC | Power supply | 5 V ±10% primary supply; powers core logic and I/O buffers |
| GND | Ground reference | Signal and power return path; requires low-impedance connection to minimize noise coupling |
Key Features
| Feature | Design Value |
|---|---|
| 64-byte page write | Reduces firmware update time by >60× vs. sequential byte writes; eliminates host-side timing constraints between bytes |
| DATA Polling on I/O7 | Enables real-time write completion detection without fixed delays or external timers-reduces system latency |
| Software Data Protection (SDP) | Three-byte unlock sequence prevents accidental writes during power transitions or noise events-no hardware modification needed |
| VCC sense & power-on delay | Automatically blocks writes until stable 5 V rail is confirmed and 5 ms debounce elapsed-eliminates brown-out corruption |
| 64-byte ID memory | Dedicated nonvolatile space at 7FC0H–7FFFH for unique device serialization or calibration data storage |
Applications
| Industrial PLC Configuration Storage | Medical Device Calibration Data |
|---|---|
Use Scenario: Storing runtime-configurable I/O mapping, PID tuning parameters, and alarm thresholds in programmable logic controllers. IC Role / Device Role / Timing Role: Nonvolatile configuration register bank accessed via parallel bus during boot and runtime reconfiguration. Use Value: Enables field updates without firmware reflashing; 100,000-cycle endurance supports decades of parameter adjustments. | Use Scenario: Retaining sensor calibration coefficients, usage logs, and safety-critical settings across power cycles in diagnostic imaging equipment. IC Role / Device Role / Timing Role: Secure, tamper-resistant parameter vault with SDP-enabled write lock during normal operation. Use Value: Prevents unintended parameter corruption during ESD events or voltage sags-ensures regulatory compliance (IEC 62304). |
| Automotive Body Control Module | Legacy Industrial HMI Firmware |
Use Scenario: Storing seat/mirror position presets, lighting profiles, and door lock configurations in 12 V vehicle subsystems. IC Role / Device Role / Timing Role: 5 V-tolerant EEPROM interfaced directly to 8-bit MCU parallel bus with no level-shifting. Use Value: Industrial temp rating ensures reliability under hood temperatures; 150 ns access avoids MCU wait states. | Use Scenario: Hosting boot loader code and UI assets in panel-mounted HMIs using aging 8051 or Z80-based controllers. IC Role / Device Role / Timing Role: Drop-in replacement for obsolete 27C256 EPROMs-supports in-system reprogramming without UV eraser. Use Value: Eliminates manual chip replacement; 3 ms page writes cut firmware update time from minutes to seconds. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar paged parallel EEPROM applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| AT28C256-15PU | 28-pin PDIP package; same electrical specs but different pinout (no DC pins); 10,000-cycle endurance | Lacks PLCC mechanical robustness and thermal performance; unsuitable for vibration-prone environments | Select when board space permits through-hole mounting and lower endurance suffices |
| M95256-DWDW | 256 Kbit SPI EEPROM; 5 MHz interface; 3 ms page write; 400 kHz I²C option available | Serial interface reduces pin count but increases software overhead; no JEDEC byte-wide compatibility | Choose for new designs prioritizing PCB density over legacy parallel bus reuse |
Compared with AT28C256EF-15JU, the AT28C256-15PU offers identical functionality in PDIP but sacrifices industrial-grade endurance and PLCC reliability, while the M95256-DWDW trades parallel simplicity for serial flexibility-making AT28C256EF-15JU optimal for drop-in upgrades of legacy 5 V systems requiring high-reliability paged writes.
Availability
AT28C256EF-15JU is available at Aetrix Electronics and suitable for industrial automation, medical diagnostics, automotive body electronics, and legacy system maintenance requiring stable component supply and long-term lifecycle support.
Supply support for AT28C256EF-15JU 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 is a global semiconductor company specializing in microcontrollers, analog devices, and nonvolatile memory solutions, with emphasis on industrial, automotive, and aerospace reliability standards.
The AT28C256 product line delivers high-endurance, paged parallel EEPROMs designed for firmware storage, configuration retention, and calibration data logging in mission-critical 5 V embedded systems.
FAQ
What is the write endurance rating of the AT28C256EF-15JU?
The AT28C256EF-15JU is rated for 100,000 write/erase cycles, as indicated by the "E" suffix in its marking code. This extended endurance supports frequent field updates in industrial controllers and medical devices where parameter recalibration occurs regularly over product lifetime.
Does the AT28C256EF-15JU require external high-voltage circuitry for programming?
No, the AT28C256EF-15JU operates from a single 5 V ±10% supply and does not require external 12 V programming voltage for standard page or byte writes. Only optional chip erase mode (not used in typical operation) requires 12 V applied to A9-standard firmware updates use only 5 V.
How does the AT28C256EF-15JU indicate write completion without polling the entire memory array?
The AT28C256EF-15JU provides two hardware-supported methods: DATA polling on I/O7 (complement of last written byte appears until completion) and toggle-bit detection on I/O6 (toggles during write, stabilizes upon finish). Both allow immediate status checking on any address-no array scanning required.
Can the AT28C256EF-15JU be used as a direct replacement for older AT28C256 variants in existing PCBs?
Yes-the AT28C256EF-15JU maintains JEDEC byte-wide pinout compatibility with all AT28C256 family members in PLCC-32 packages. Its "F" suffix denotes 3 ms fast page write, and "E" confirms 100K endurance; no PCB changes are needed beyond verifying DC pin handling matches the datasheet requirement.
What is the function of the two DC pins on the AT28C256EF-15JU PLCC package?
The two DC (Don't Connect) pins-located at positions 1 and 17 on the AT28C256EF-15JU PLCC package-have no internal die connection and must remain unconnected on the PCB. Soldering, routing, or applying bias to either pin violates Microchip's design specification and may cause functional failure.
AT28C256EF-15JU 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:
- 150 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)
AT28C256EF-15JU FAQ
1.How can I place an order for AT28C256EF-15JU through Aetrix?
Please submit a Request for Quotation (RFQ) for AT28C256EF-15JU 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 AT28C256EF-15JU reliable?
The price and inventory of AT28C256EF-15JU are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for AT28C256EF-15JU is usually 5 days.
3.What payment methods are accepted for AT28C256EF-15JU?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for AT28C256EF-15JU transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for AT28C256EF-15JU?
AT28C256EF-15JU orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your AT28C256EF-15JU 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 AT28C256EF-15JU?
For technical support, including AT28C256EF-15JU datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your AT28C256EF-15JU requirements.
6.How does Aetrix verify that AT28C256EF-15JU is sourced from the original manufacturer or authorized distributors?
All AT28C256EF-15JU 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 AT28C256EF-15JU meets industry standards.
7.What is the process for return or replacement of AT28C256EF-15JU?
All AT28C256EF-15JU units undergo pre-shipment inspection (PSI). If there is an issue with AT28C256EF-15JU, 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 AT28C256EF-15JU part is unused and in its original packaging.
Return procedure for AT28C256EF-15JU:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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