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Microchip Technology AT28LV256-25TC
- Part No.:
- AT28LV256-25TC
- Manufacturer:
- Microchip Technology
- Category:
- Memory
- Package:
- 28-TSSOP (0.465", 11.80mm Width)
- Datasheet:
-
AT28LV256-25TC.pdf
- Description:
- IC EEPROM 256KBIT PAR 28TSOP
- Quantity:
- Payment:
- Shipping:
Inventory:4,666
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Product details
Overview
AT28LV256-25TC from Atmel is a 256 Kbit (32K × 8) parallel EEPROM with JEDEC-standard byte-wide pinout, 3.0–3.6 V single-supply operation, 250 ns read access time, and hardware/software data protection. It supports page write (1–64 bytes), DATA polling, and Toggle Bit for write completion detection - used in industrial control firmware storage and embedded boot memory.
For engineers reviewing the AT28LV256-25TC datasheet, AT28LV256-25TC pinout, AT28LV256-25TC application, or AT28LV256-25TC equivalent, key selection criteria include low-voltage compatibility, page-write timing (≤10 ms), CMOS standby current (≤20 µA), endurance (10,000 cycles), and JEDEC-compliant 28-pin TSOP packaging.
Technical Context
The AT28LV256-25TC operates as a drop-in SRAM-compatible nonvolatile memory: CE/OE/WE control enables standard bus interfacing without external logic. Its internal 64-byte page register latches address and data on falling CE or WE edges, decoupling the host bus during autonomous internal programming.
Write completion is verified via I/O7 DATA polling (complement-to-data toggle) or I/O6 Toggle Bit behavior, both functional across all operating modes. Hardware protection includes VCC power-on delay (~10 ms), noise filtering (<15 ns pulse rejection), and active inhibit states (CE high, OE low, or WE high).
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Memory Size | 256 Kbit (32,768 × 8 bits) - supports full firmware image storage for microcontrollers with 8-bit data buses. |
| Read Access Time | 250 ns max - compatible with 4 MHz system clocks and legacy ISA/PCI bus timing budgets. |
| Page Write Cycle | ≤10 ms - enables efficient bulk configuration updates without blocking host CPU for extended periods. |
| VCC Supply Range | 3.0 V to 3.6 V - interoperable with 3.3 V logic families and eliminates need for level shifters. |
| Standby Current | 20 µA (CMOS) - suitable for battery-backed systems requiring ultra-low quiescent power. |
| Endurance | 10,000 write/erase cycles - sufficient for field-upgradable calibration tables and parameter logging. |
| Data Retention | 10 years at 85°C - meets industrial temperature lifecycle requirements for unattended equipment. |
Pinout & Package
AT28LV256-25TC uses a 28-lead Plastic Thin Small Outline Package (TSOP), 8 mm × 13.4 mm body, 0.55 mm pitch, JEDEC MO-153 compliant. Pin 1 index marked, lead finish SnPb or RoHS-compliant matte tin.
| 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 | 8-bit parallel interface; I/O7 provides DATA polling status, I/O6 delivers Toggle Bit confirmation. |
| CE | Chip Enable | Active-low chip select; must be stable before address setup; inhibits writes when high. |
| OE | Output Enable | Active-low output control; enables read data drive; high-Z when deasserted to prevent bus contention. |
| WE | Write Enable | Active-low write strobe; falling edge latches address/data; combined with CE for robust write initiation. |
| VCC | Power Supply | 3.0–3.6 V supply; internal voltage monitor enforces 10 ms power-on write inhibit delay. |
| GND | Ground Reference | Signal and power return; decoupling capacitor required within 10 mm of VCC pin. |
Key Features
| Feature | Design Value |
|---|---|
| Software Data Protection (SDP) | Three-step unlock sequence (5555H/2AAAH/5555H) required before each write - prevents corruption during power transients. |
| Hardware Write Inhibit | Automatic 10 ms VCC power-on delay + noise-filtered CE/WE inputs - eliminates false writes from supply bounce or EMI. |
| Page Write Architecture | Internal 64-byte latch allows burst loading of up to 64 bytes within 150 µs intervals - reduces host bus occupancy by >90% vs. byte writes. |
| JEDEC Byte-Wide Pinout | Pin-compatible with industry-standard EPROMs and SRAMs (e.g., 27C256, 62256) - enables direct replacement in existing PCB layouts. |
| Device Identification Area | 64-byte reserved sector (7FC0H–7FFFH) accessible via 12 V on A9 - supports unique device serialization and traceability. |
Applications
| Industrial PLC Firmware Storage | Medical Device Calibration Memory |
|---|---|
|
Use Scenario: Storing firmware update images and configuration parameters in programmable logic controllers deployed in factory automation environments. IC Role / Device Role / Timing Role: Nonvolatile program memory with SRAM-like read interface and page-write efficiency for field upgrades. Use Value: 250 ns read speed ensures real-time instruction fetch; 10,000-cycle endurance supports quarterly firmware revisions over 10+ year product life. |
Use Scenario: Retaining calibrated sensor offsets and safety-critical operational limits in portable diagnostic equipment operating across -40°C to +85°C. IC Role / Device Role / Timing Role: Temperature-stable configuration storage with hardware write protection against accidental reprogramming during battery swaps. Use Value: 20 µA standby current extends battery life; industrial temp range (-40°C to +85°C) and 10-year data retention meet IEC 62304 Class C requirements. |
| Telecom Line Card Boot Memory | Automotive Body Control Module NVM |
|
Use Scenario: Holding bootloader code and initialization tables for FPGA-based line cards in carrier-grade DSLAMs and OLTs. IC Role / Device Role / Timing Role: Parallel boot ROM accessed directly by microprocessor address/data bus during power-on reset sequence. Use Value: JEDEC pinout enables drop-in replacement of obsolete EPROMs; 3.3 V compatibility avoids level-shifter redesign. |
Use Scenario: Storing vehicle-specific configuration (e.g., door lock logic, mirror position presets) in BCMs subject to automotive thermal cycling. IC Role / Device Role / Timing Role: Robust parameter memory with dual hardware/software write protection to prevent corruption during ignition transients. Use Value: 12 V A9 programming mode enables secure device ID writing during manufacturing; 10,000-cycle rating exceeds OEM 15-year service life targets. |
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 | 256 Kbit, 3.3 V, 200 ns access, but requires 5 V for write operations and lacks software data protection. | Not suitable for fully 3.3 V-only systems; higher VPP complexity increases BOM count and layout area. | Select only if legacy 5 V programming infrastructure exists and SDP is not required. |
| Microchip 25LC256-I/P | 256 Kbit SPI EEPROM, 3.3 V, 5 ms page write, no parallel bus interface - serial protocol only. | Requires MCU SPI peripheral and firmware driver; incompatible with SRAM-style bus-mapped access. | Choose only for new designs where board space is constrained and SPI is already utilized for other peripherals. |
Compared with ST M28W256FCT and Microchip 25LC256-I/P, the AT28LV256-25TC uniquely delivers true 3.3 V-only operation with JEDEC-compliant parallel interface, integrated SDP, and deterministic 10 ms page write - enabling direct replacement in legacy SRAM/EPROM sockets without redesign.
Availability
AT28LV256-25TC is available at Aetrix Electronics and suitable for industrial control firmware storage, medical device calibration memory, and telecom line card boot memory requiring stable component supply, long-term lifecycle support, and RoHS-compliant TSOP packaging.
Supply support for AT28LV256-25TC 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 security ICs for industrial, automotive, and communications markets.
The AT28LV256-25TC belongs to Atmel's Low-Voltage™ Parallel EEPROM product line, designed specifically for 3.3 V embedded systems needing SRAM-compatible nonvolatile storage with robust write protection and industrial temperature operation.
FAQ
What is the maximum read access time specified for the AT28LV256-25TC?
The AT28LV256-25TC has a maximum read access time of 250 ns under commercial temperature conditions (0°C to 70°C) and 3.0–3.6 V supply. This value is guaranteed across the full operating voltage and temperature range, ensuring reliable timing integration into 4 MHz bus systems without wait-state insertion. The AT28LV256-25TC achieves this using optimized CMOS decoding and output drivers, consistent with its JEDEC byte-wide pinout compatibility.
Does the AT28LV256-25TC support page write operations, and what is the maximum page size?
Yes, the AT28LV256-25TC supports page write operations with a fixed 64-byte page size. Up to 64 bytes can be loaded sequentially within 150 µs intervals, after which the internal timer initiates autonomous programming. The AT28LV256-25TC uses A6–A14 to define the page boundary, and all addresses in a given page write must share identical A6–A14 values - enabling efficient firmware patching without repeated address setup overhead.
How does hardware write protection work on the AT28LV256-25TC?
The AT28LV256-25TC implements three hardware write protection mechanisms: (1) a 10 ms VCC power-on delay that blocks writes until supply stabilizes; (2) active inhibition when CE is high, OE is low, or WE is high; and (3) input noise filtering rejecting pulses <15 ns on CE/WE. These features ensure the AT28LV256-25TC remains immune to spurious writes during power sequencing, ESD events, or signal crosstalk - critical for unattended industrial deployments.
Can the AT28LV256-25TC be used in industrial temperature applications?
Yes, the AT28LV256-25TC is qualified for industrial temperature operation from -40°C to +85°C, as confirmed by its ordering code suffix "TI" (industrial) and "TC" (TSOP package). Its 10-year data retention and 10,000-cycle endurance are validated across this full range. The AT28LV256-25TC maintains 250 ns read access and ≤10 ms page write performance throughout the industrial temperature envelope, making it suitable for harsh-environment control systems.
What is the purpose of the extra 64-byte EEPROM section in the AT28LV256-25TC?
The AT28LV256-25TC includes an additional 64-byte EEPROM segment (addresses 7FC0H–7FFFH) accessible only when A9 is raised to 12.0 V ± 0.5 V. This area is intended for permanent device identification, manufacturing traceability, or secure key storage - isolated from normal read/write operations. Unlike main array accesses, this region requires elevated voltage and dedicated programming sequences, ensuring the AT28LV256-25TC supports secure provisioning without compromising main memory reliability.
AT28LV256-25TC Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Microchip Technology
- Series:
- -
- Package/Case:
- 28-TSSOP (0.465", 11.80mm Width)
- Packaging:
- Tray
- 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:
- 0°C ~ 70°C (TC)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 28-TSOP
AT28LV256-25TC FAQ
1.How can I place an order for AT28LV256-25TC through Aetrix?
Please submit a Request for Quotation (RFQ) for AT28LV256-25TC 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 AT28LV256-25TC reliable?
The price and inventory of AT28LV256-25TC are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for AT28LV256-25TC is usually 5 days.
3.What payment methods are accepted for AT28LV256-25TC?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for AT28LV256-25TC transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for AT28LV256-25TC?
AT28LV256-25TC orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your AT28LV256-25TC 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 AT28LV256-25TC?
For technical support, including AT28LV256-25TC datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your AT28LV256-25TC requirements.
6.How does Aetrix verify that AT28LV256-25TC is sourced from the original manufacturer or authorized distributors?
All AT28LV256-25TC 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 AT28LV256-25TC meets industry standards.
7.What is the process for return or replacement of AT28LV256-25TC?
All AT28LV256-25TC units undergo pre-shipment inspection (PSI). If there is an issue with AT28LV256-25TC, 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 AT28LV256-25TC part is unused and in its original packaging.
Return procedure for AT28LV256-25TC:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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