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Microchip Technology AT28LV256-25JI
- Part No.:
- AT28LV256-25JI
- Manufacturer:
- Microchip Technology
- Category:
- Memory
- Package:
- 32-LCC (J-Lead)
- Datasheet:
-
AT28LV256-25JI.pdf
- Description:
- IC EEPROM 256KBIT PAR 32PLCC
- Quantity:
- Payment:
- Shipping:
Inventory:2,502
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Product details
Overview
AT28LV256-25JI from Atmel is a 256 Kbit (32K × 8) low-voltage parallel EEPROM with JEDEC-standard byte-wide pinout, 250 ns read access time, 10 ms maximum page write cycle time, and operation over -40°C to +85°C industrial temperature range. It supports automatic 1–64-byte page writes, DATA polling, and hardware/software data protection for embedded firmware storage in microcontroller systems.
For engineers reviewing the AT28LV256-25JI datasheet, AT28LV256-25JI pinout, AT28LV256-25JI application, or AT28LV256-25JI equivalent, key selection criteria include its 3.0–3.6 V single-supply operation, CMOS standby current of 20 µA, 10,000 write endurance cycles, 10-year data retention, and compatibility with standard SRAM-like bus interfaces in legacy industrial controllers.
Technical Context
The AT28LV256-25JI implements a parallel EEPROM architecture with internal 64-byte page latches and an autonomous control timer that manages full-page programming without external timing logic. Its dual-line chip enable (CE) and output enable (OE) control enables flexible bus contention management in multi-peripheral systems.
Write operations are secured via hardware mechanisms-including VCC power-on delay, noise filtering on WE/CE inputs, and write-inhibit states-and software data protection requiring a three-byte unlock sequence before each write. Device identification uses dedicated 64-byte EEPROM space accessible via A9 = 12V.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Memory Size | 256 Kbit (32,768 × 8), directly addressable as byte-wide SRAM-compatible memory |
| Read Access Time | 250 ns max - determines minimum CPU wait-state insertion for 8-bit bus interfacing |
| Page Write Cycle Time | 10 ms max - defines firmware update latency per 64-byte block in field-programmable applications |
| VCC Supply Range | 3.0 V to 3.6 V - enables direct connection to 3.3 V logic rails without level-shifting |
| Standby Current | 20 µA (CMOS) - supports ultra-low-power retention in battery-backed industrial modules |
| Endurance & Retention | 10,000 write cycles / 10 years data retention - validated for infrequent configuration storage in PLCs and instrumentation |
| Operating Temperature | -40°C to +85°C - qualified for deployment in uncontrolled industrial enclosures and outdoor edge nodes |
Pinout & Package
AT28LV256-25JI is supplied in a 32-lead Plastic J-leaded Chip Carrier (PLCC) package per JEDEC MS-016 AE. Pins 1 and 17 are designated "DON'T CONNECT" and must remain unconnected in PCB layout.
| 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 | Byte-wide data path used for both read output and write input; I/O7 provides DATA polling status during writes |
| CE | Chip Enable | Active-low device select; when high, forces outputs to high-impedance and inhibits all writes |
| OE | Output Enable | Active-low read control; used with CE to prevent bus contention during shared-memory access |
| WE | Write Enable | Active-low write strobe; falling edge latches address/data; combined with CE for byte/page write initiation |
| VCC | Power Supply | +3.0 V to +3.6 V supply; includes internal power-on delay circuitry for write safety |
| GND | Ground Reference | Signal and power return; required for stable 20 µA standby current and noise-immune DATA polling |
| NC / DC | No Connect / Don't Connect | Pins 1 and 17 - physically present but electrically unused; must be left floating per datasheet |
Key Features
| Feature | Design Value |
|---|---|
| JEDEC Byte-Wide Pinout | Direct drop-in replacement for industry-standard 27C256 and 28C256 sockets in legacy designs |
| Automatic Page Write | Reduces firmware update time by up to 64× vs. byte-by-byte writes, with no external timing circuitry needed |
| DATA Polling (I/O7) | Enables real-time write completion detection without busy-wait loops or external interrupt signals |
| Software Data Protection | Three-byte unlock sequence prevents accidental writes during power transitions or system resets |
| Dedicated ID Memory | 64-byte user-accessible EEPROM space at 7FC0H–7FFFH for calibration data, serial numbers, or firmware version stamps |
Applications
| Industrial PLC Configuration Storage | Embedded Microcontroller Bootloader Parameters |
|---|---|
Use Scenario: Storing I/O mapping tables, PID tuning constants, and alarm thresholds in programmable logic controllers deployed in factory automation lines. IC Role / Device Role / Timing Role: Nonvolatile parameter store accessed during cold start and runtime reconfiguration; operates as SRAM-mapped peripheral on 8-bit data bus. Use Value: Enables field-upgradable machine behavior without firmware reflashing; 10,000-cycle endurance supports decades of maintenance cycles under industrial duty. |
Use Scenario: Holding bootloader configuration flags, secure boot keys, and hardware revision identifiers in ARM Cortex-M or 8051-based edge sensor nodes. IC Role / Device Role / Timing Role: Early-boot configuration register accessed before RAM initialization; supports 250 ns read timing for deterministic startup sequences. Use Value: Guarantees safe boot state persistence across brownouts; software data protection prevents corruption during unstable power ramp-up. |
| Medical Device Calibration Data | Telecom Line Card Firmware Patch Storage |
Use Scenario: Archiving sensor calibration coefficients, date-stamped diagnostics, and regulatory compliance logs in portable diagnostic equipment. IC Role / Device Role / Timing Role: Tamper-resistant nonvolatile memory with 10-year data retention; accessed via isolated SPI-to-parallel bridge or direct MCU bus interface. Use Value: Meets IEC 62304 data integrity requirements; hardware write inhibit ensures calibration data remains intact during ESD events or power surges. |
Use Scenario: Storing hot-swappable firmware patches and feature-enable bits in carrier-grade DSLAM line cards operating in telecom central offices. IC Role / Device Role / Timing Role: Field-updatable configuration memory co-located with DSPs; supports concurrent read/write via page-write mode during service windows. Use Value: 10 ms page write enables sub-second patch deployment; JEDEC pinout allows reuse of existing PCB footprints across product generations. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar parallel EEPROM applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| AT28C256-15PI | 5V-only supply (4.5–5.5 V); 150 ns access; no low-voltage operation | Requires level-shifting in 3.3 V systems; higher active current (20 mA) | Select only if legacy 5V bus architecture prohibits voltage translation |
| MN63C256F-25PL | Same 3.0–3.6 V supply and 250 ns timing; PLCC-32 package; identical pinout | Manufactured by Macronix; fully pin- and function-compatible per JEDEC MS-016 AE | Drop-in alternative with same industrial temp rating and page-write behavior |
Compared with AT28LV256-25JI, AT28C256-15PI demands 5V infrastructure and lacks low-power standby capability, while MN63C256F-25PL offers identical electrical and mechanical compatibility-making it the preferred second-source option for long-term supply continuity.
Availability
AT28LV256-25JI is available at Aetrix Electronics and suitable for industrial PLCs, medical diagnostic instruments, telecom line cards, and embedded controller bootloaders requiring stable component supply across extended product lifecycles.
Supply support for AT28LV256-25JI 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
Atmel Corporation was a U.S.-based semiconductor company specializing in microcontrollers, nonvolatile memory, and security ICs, later acquired by Microchip Technology in 2016.
The AT28LV256 product line was designed for reliable, low-voltage firmware and configuration storage in industrial, medical, and telecom systems where SRAM-like interface simplicity and long-term data integrity are critical.
FAQ
What is the operating voltage range for the AT28LV256-25JI?
The AT28LV256-25JI operates from 3.0 V to 3.6 V DC. This single-supply range eliminates the need for separate 5 V rails and allows direct integration with 3.3 V microcontrollers and FPGAs. Operation outside this range may cause undefined behavior or permanent damage, as specified in the Absolute Maximum Ratings section of the datasheet.
Does the AT28LV256-25JI support true page writes without external timing components?
Yes, the AT28LV256-25JI includes an internal control timer and 64-byte page latch, enabling autonomous page writes of 1–64 bytes after a single WE or CE strobe. No external clock, delay circuit, or microcontroller wait-state management is required-reducing BOM count and firmware complexity in AT28LV256-25JI-based designs.
How is write protection implemented on the AT28LV256-25JI?
The AT28LV256-25JI implements dual-layer write protection: hardware-level inhibition via VCC power-on delay, OE/CE/WE state monitoring, and noise filtering; and software-level protection requiring a precise three-byte unlock sequence (0xAA → 0x55 → 0xA0) before any write. Both layers must be satisfied for AT28LV256-25JI to accept data.
Can the AT28LV256-25JI be used as a direct replacement for older 27C256 EPROMs?
No-the AT28LV256-25JI is an EEPROM with electrically erasable memory and requires no UV erasure, unlike one-time-programmable 27C256 EPROMs. While it shares JEDEC byte-wide pinout and 32K × 8 organization, AT28LV256-25JI supports in-system reprogramming and has different timing, voltage, and control signal requirements.
What is the purpose of the 64-byte device identification area in the AT28LV256-25JI?
The AT28LV256-25JI includes 64 bytes of dedicated EEPROM space (addresses 7FC0H–7FFFH) accessible when A9 is raised to 12.0 V ± 0.5 V. This area is intended for storing unique device identifiers, calibration data, manufacturing lot codes, or firmware version stamps-separate from main memory and protected from routine write operations.
AT28LV256-25JI 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:
- 250 ns
- Voltage - Supply:
- 3V ~ 3.6V
- Operating Temperature:
- -40°C ~ 85°C (TC)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 32-PLCC (13.97x11.43)
AT28LV256-25JI FAQ
1.How can I place an order for AT28LV256-25JI through Aetrix?
Please submit a Request for Quotation (RFQ) for AT28LV256-25JI 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 AT28LV256-25JI reliable?
The price and inventory of AT28LV256-25JI are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for AT28LV256-25JI is usually 5 days.
3.What payment methods are accepted for AT28LV256-25JI?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for AT28LV256-25JI transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for AT28LV256-25JI?
AT28LV256-25JI orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your AT28LV256-25JI 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 AT28LV256-25JI?
For technical support, including AT28LV256-25JI datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your AT28LV256-25JI requirements.
6.How does Aetrix verify that AT28LV256-25JI is sourced from the original manufacturer or authorized distributors?
All AT28LV256-25JI 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 AT28LV256-25JI meets industry standards.
7.What is the process for return or replacement of AT28LV256-25JI?
All AT28LV256-25JI units undergo pre-shipment inspection (PSI). If there is an issue with AT28LV256-25JI, 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 AT28LV256-25JI part is unused and in its original packaging.
Return procedure for AT28LV256-25JI:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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