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Microchip Technology AT28LV256-20JI
- Part No.:
- AT28LV256-20JI
- Manufacturer:
- Microchip Technology
- Category:
- Memory
- Package:
- 32-LCC (J-Lead)
- Datasheet:
-
AT28LV256-20JI.pdf
- Description:
- IC EEPROM 256KBIT PAR 32PLCC
- Quantity:
- Payment:
- Shipping:
Inventory:2,842
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Product details
Overview
AT28LV256-20JI from Atmel is a 256 Kbit (32K × 8) parallel EEPROM with JEDEC-standard byte-wide pinout, 3.0–3.6 V single-supply operation, 200 ns read access time, and industrial temperature range (−40°C to +85°C). It supports automatic 1–64-byte page writes with internal latching and timer, and features hardware/software data protection for embedded control and firmware storage applications.
For engineers reviewing the AT28LV256-20JI datasheet, AT28LV256-20JI pinout, AT28LV256-20JI application, or AT28LV256-20JI equivalent, key selection criteria include low-voltage compatibility, page-write timing (≤10 ms), CMOS standby current (≤50 µA), DATA polling support via I/O7, and PLCC-32 packaging for ruggedized industrial PCB layouts.
Technical Context
The AT28LV256-20JI operates as a drop-in SRAM-compatible nonvolatile memory: reads require CE and OE low with WE high; writes initiate on WE or CE low pulse while OE is high. Its internal 64-byte page register latches address and data on falling CE/WE edges, enabling bus release during internal programming.
Write completion is verified via DATA polling (I/O7 complement-to-data toggle) or TOGGLE BIT (I/O6 toggling), both usable at any point during tWC (≤10 ms). Hardware protection includes VCC power-on delay (~10 ms), noise filtering (<15 ns pulse rejection), and write inhibit via CE/OE/WE logic states.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Memory Density | 256 Kbit (32,768 × 8 bits) - supports firmware image storage or configuration tables in microcontroller-based systems. |
| Read Access Time | 200 ns max - enables direct replacement of SRAM in legacy 8-bit bus systems without timing redesign. |
| Page Write Cycle | ≤10 ms - reduces firmware update latency versus byte-by-byte writes; supports burst programming of up to 64 bytes per cycle. |
| VCC Supply Range | 3.0 V to 3.6 V - compatible with modern low-voltage logic families and battery-backed industrial controllers. |
| Standby Current | 50 µA max (industrial temp.) - minimizes quiescent power in always-on monitoring devices. |
| Data Retention | 10 years - ensures long-term reliability in unattended equipment like remote sensors or PLC modules. |
| Endurance | 10,000 write cycles - sufficient for infrequent parameter updates in calibration or configuration storage. |
Pinout & Package
AT28LV256-20JI uses a 32-lead Plastic J-Leaded Chip Carrier (PLCC-32) package with lead pitch 1.27 mm and body size 11.9 × 11.9 mm. Pins 1 and 17 are designated "DON'T CONNECT" per datasheet.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| A0–A14 | Address Inputs | 15-bit address bus for 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; I/O7 used for DATA polling, I/O6 for TOGGLE BIT status indication. |
| CE | Chip Enable | Active-low chip select; must be low with OE low for read, or low with OE high for write initiation. |
| OE | Output Enable | Active-low output control; high during write to prevent bus contention; required high for byte/page write start. |
| WE | Write Enable | Active-low write strobe; falling edge latches address/data; used with CE for dual-control write safety. |
| VCC | Power Supply | +3.0 V to +3.6 V supply; internal voltage monitor enforces 10 ms power-on delay before write enable. |
| GND | Ground Reference | Signal and power ground; decoupling capacitor placement near pin critical for noise immunity during page writes. |
| NC / DC | No Connect / Don't Connect | Pins 1 and 17 are unconnected; must remain floating-no pull-up/down or routing allowed. |
Key Features
| Feature | Design Value |
|---|---|
| Software Data Protection (SDP) | Three-step unlock sequence (5555H/2AAAH/A0H) required before each write-prevents corruption during power transients. |
| Hardware Write Inhibit | Automatic disable if CE high, OE low, or WE high-ensures no accidental writes during reset or brown-out conditions. |
| Internal Page Register | 64-byte latch buffers entire page; frees system bus after initial address/data load, improving host CPU efficiency. |
| Device Identification Area | 64-byte reserved sector (7FC0H–7FFFH) accessible at 12 V on A9-enables unique serialization or calibration data storage. |
| JEDEC Byte-Wide Pinout | Pin-compatible with industry-standard EPROM/EEPROM sockets-simplifies migration from obsolete 27C256 or 28C256 designs. |
Applications
| Industrial PLC Configuration Storage | Medical Device Calibration Data |
|---|---|
Use Scenario: Storing user-configurable I/O mapping and alarm thresholds in programmable logic controllers deployed in factory automation. IC Role / Device Role / Timing Role: Nonvolatile configuration memory accessed via 8-bit parallel bus; retains settings across power cycles with 10-year data retention. Use Value: Eliminates need for battery-backed SRAM; SDP and hardware write inhibit prevent misconfiguration during EMI-rich plant-floor operation. |
Use Scenario: Holding factory-calibrated sensor offsets and gain coefficients in portable diagnostic instruments requiring regulatory traceability. IC Role / Device Role / Timing Role: Secure parameter storage with device ID sector (7FC0H–7FFFH) for audit-ready calibration logging. Use Value: 12 V-programmable ID area enables unique device serialization; 10,000-cycle endurance supports field recalibration over product lifetime. |
| Avionics Bootloader Image | Energy Meter Firmware Patch Storage |
Use Scenario: Storing fail-safe bootloader code in airborne control units where radiation tolerance and long-term reliability are critical. IC Role / Device Role / Timing Role: Read-only execution source during cold start; 200 ns access meets real-time boot timing constraints. Use Value: Industrial temperature rating (−40°C to +85°C) and 10-year retention ensure integrity across flight cycles and storage periods. |
Use Scenario: Hosting firmware patches downloaded over PLC or RF links in smart electricity meters deployed in utility substations. IC Role / Device Role / Timing Role: Field-upgradable code storage using page writes (≤10 ms/cycle) to minimize service interruption. Use Value: Low 50 µA standby current extends battery life during mesh-network sleep modes; DATA polling simplifies host MCU firmware. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar parallel EEPROM applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| ST M28W256FCT | 5V-only supply (4.5–5.5 V); 250 ns read access; TSOP-32 package only. | Requires level-shifting for 3.3 V systems; lacks software data protection and 12 V ID sector. | Select only if legacy 5 V design exists and low-voltage operation is not required. |
| Microchip 25LC256-I/P | Serial SPI interface (not parallel); 3.3 V compatible; 5 ms page write; 1 MHz max clock. | Reduces pin count but increases firmware overhead; incompatible with existing 8-bit bus architecture. | Choose for new compact designs prioritizing board space over bus speed; not a drop-in replacement. |
Compared with ST M28W256FCT and Microchip 25LC256-I/P, the AT28LV256-20JI uniquely combines 3.3 V operation, JEDEC byte-wide pinout, integrated SDP, and industrial temperature support-making it the only direct upgrade path for legacy 27C256/28C256-based systems requiring low-voltage compliance and robust write protection.
Availability
AT28LV256-20JI is available at Aetrix Electronics and suitable for industrial PLC configuration storage, medical device calibration data retention, avionics bootloader image hosting, energy meter firmware patch storage, and embedded system parameter backup requiring stable component supply across extended lifecycles.
Supply support for AT28LV256-20JI 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 (now part of Microchip Technology) is a fabless semiconductor company specializing in microcontrollers, nonvolatile memory, and secure authentication ICs for industrial, automotive, and consumer applications.
The AT28LV256-20JI belongs to Atmel's Low-Voltage™ Parallel EEPROM product line, designed specifically for replacing obsolete 5 V EPROMs/EEPROMs in industrial control, instrumentation, and telecom infrastructure where 3.3 V compatibility and enhanced data integrity are mandatory.
FAQ
What is the operating temperature range for the AT28LV256-20JI?
The AT28LV256-20JI is rated for industrial temperature operation from −40°C to +85°C. This specification is confirmed in the "DC and AC Operating Range" table on page 4 of the official Atmel datasheet (Rev. 2400AX), and applies specifically to all part numbers ending in "JI", including the AT28LV256-20JI. The extended range ensures reliable performance in harsh environments such as factory floors, outdoor utility meters, and vehicle-mounted control units.
Does the AT28LV256-20JI support page write operations, and what is the maximum page size?
Yes, the AT28LV256-20JI supports page write operations with a fixed page size of 64 bytes. As documented in the "Features" and "Device Operation" sections, the internal page register latches 1 to 64 bytes of data, and all addresses within a single page write must share identical A6–A14 values. The maximum page write cycle time is 10 ms, and successive bytes must be loaded within 150 µs (tBLC) to remain within the same page operation.
How is write completion detected on the AT28LV256-20JI?
Write completion on the AT28LV256-20JI can be detected using either DATA polling on I/O7 or the TOGGLE BIT on I/O6. During a write, reading the last written byte returns its complement on I/O7; when true data appears, the write is complete. Alternatively, I/O6 toggles between 0 and 1 until completion, then stabilizes. Both methods are valid at any time during the write cycle and are fully supported in the AT28LV256-20JI's silicon revision.
What package type does the AT28LV256-20JI use, and are there any special handling requirements?
The AT28LV256-20JI uses a 32-lead Plastic J-Leaded Chip Carrier (PLCC-32) package, per the "Ordering Information" table on page 9 and "Packaging Information" on page 11. Pins 1 and 17 are explicitly marked "DON'T CONNECT" and must remain unconnected-no soldering, routing, or termination is permitted. The package requires standard PLCC socket or reflow profile compatible with JEDEC MS-016AE specifications.
Is software data protection (SDP) enabled by default on the AT28LV256-20JI, and how is it activated?
Yes, software data protection (SDP) is active by default on the AT28LV256-20JI. To enable writing, the host must first issue a three-byte unlock sequence: write 0xAA to address 0x5555, then 0x55 to address 0x2AAA, then 0xA0 to address 0x5555. This sequence must precede every byte or page write operation. If omitted, the AT28LV256-20JI enters polling mode for tWC duration but writes no data-ensuring zero-risk inadvertent modification.
AT28LV256-20JI 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:
- 200 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)
AT28LV256-20JI FAQ
1.How can I place an order for AT28LV256-20JI through Aetrix?
Please submit a Request for Quotation (RFQ) for AT28LV256-20JI 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 AT28LV256-20JI reliable?
The price and inventory of AT28LV256-20JI are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for AT28LV256-20JI is usually 5 days.
3.What payment methods are accepted for AT28LV256-20JI?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for AT28LV256-20JI transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for AT28LV256-20JI?
AT28LV256-20JI orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your AT28LV256-20JI 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 AT28LV256-20JI?
For technical support, including AT28LV256-20JI datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your AT28LV256-20JI requirements.
6.How does Aetrix verify that AT28LV256-20JI is sourced from the original manufacturer or authorized distributors?
All AT28LV256-20JI 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 AT28LV256-20JI meets industry standards.
7.What is the process for return or replacement of AT28LV256-20JI?
All AT28LV256-20JI units undergo pre-shipment inspection (PSI). If there is an issue with AT28LV256-20JI, 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 AT28LV256-20JI part is unused and in its original packaging.
Return procedure for AT28LV256-20JI:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
AT28LV256-20JI Tags
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M24C02-WMN6TP
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AT24C02C-XHM-T
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AT21CS01-STUM10-T
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24LC01BT-I/OT
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M24C02-FMC6TG
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AT24CS02-SSHM-T
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93LC46BT-I/OT
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AT24C04C-SSHM-T
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24LC01BT-I/SN
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