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Microchip Technology AT28LV256-25TI
- Part No.:
- AT28LV256-25TI
- Manufacturer:
- Microchip Technology
- Category:
- Memory
- Package:
- 28-TSSOP (0.465", 11.80mm Width)
- Datasheet:
-
AT28LV256-25TI.pdf
- Description:
- IC EEPROM 256KBIT PAR 28TSOP
- Quantity:
- Payment:
- Shipping:
Inventory:1,345
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Product details
Overview
AT28LV256-25TI from Atmel is a 256 Kbit (32K × 8) low-voltage parallel EEPROM with JEDEC-standard byte-wide pinout, 250 ns read access time, 3.0–3.6 V single-supply operation, and industrial temperature range (−40°C to +85°C), used for nonvolatile data storage in embedded control and firmware configuration circuits.
For engineers reviewing the AT28LV256-25TI datasheet, AT28LV256-25TI pinout, AT28LV256-25TI application, or AT28LV256-25TI equivalent, key selection considerations include page-write capability (1–64 bytes), DATA polling/Toggle Bit write completion detection, hardware/software data protection, CMOS standby current (20 µA), and compatibility with SRAM-like bus interface timing.
Technical Context
The AT28LV256-25TI operates as a byte-addressable parallel EEPROM with internal 64-byte page latching and autonomous internal control timer for page write execution. It supports both byte and page write modes without external timing components and uses standard SRAM-style control signals (CE/OE/WE).
Write completion is verified via DATA polling on I/O7 or Toggle Bit behavior on I/O6; software data protection requires a three-byte unlock sequence before any write. The device includes 64 bytes of dedicated identification memory accessible at 7FC0H–7FFFH using A9 = 12 V.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Memory Density | 256 Kbit (32,768 × 8 bits) - provides sufficient space for boot code, calibration tables, or configuration parameters in resource-constrained systems. |
| Read Access Time | 250 ns max - enables direct replacement of fast SRAM in legacy designs requiring nonvolatile retention. |
| Page Write Cycle Time | 10 ms max - allows efficient bulk updates without host CPU blocking for extended durations. |
| VCC Supply Range | 3.0 V to 3.6 V - compatible with modern low-voltage microcontroller I/O domains and eliminates need for level-shifting. |
| Standby Current | 20 µA (CMOS, industrial temp) - supports ultra-low-power operation in battery-backed or energy-sensitive applications. |
| Endurance | 10,000 write/erase cycles - suitable for infrequent configuration updates, not high-frequency logging. |
| Data Retention | 10 years - ensures long-term reliability for deployed industrial or automotive electronics without refresh. |
Pinout & Package
AT28LV256-25TI is available in 28-lead TSOP (28T) package per JEDEC MS-024AA, with 14 pins per side, gull-wing leads, and 0.55 mm pitch. Pin 1 marked by notch or bevel; pin 14 = GND, pin 15 = VCC.
| 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 | Byte-wide data path; I/O7 used for DATA polling, I/O6 for Toggle Bit status indication during writes. |
| CE | Chip Enable | Active-low chip select; must be low with OE low and WE high for read; inhibits writes when high. |
| OE | Output Enable | Active-low output control; places I/O lines in high-impedance state when high, preventing bus contention. |
| WE | Write Enable | Active-low write strobe; falling edge latches address/data; used with CE for byte/page write initiation. |
| GND / VCC | Power Terminals | Ground (Pin 14) and 3.0–3.6 V supply (Pin 15); decoupling capacitor required near VCC pin for stable operation. |
Key Features
| Feature | Design Value |
|---|---|
| JEDEC Byte-Wide Pinout | Direct drop-in replacement for industry-standard 27C256/27C512 EPROMs and many SRAMs in existing PCB layouts. |
| 64-Byte Page Write | Reduces host processor overhead by enabling up to 64 bytes to be loaded and committed in one internal programming cycle. |
| DATA Polling & Toggle Bit | Hardware-supported write completion detection without requiring fixed delay timers or external status lines. |
| Software Data Protection | Three-byte unlock sequence prevents accidental writes during power-up/down or noise events, eliminating need for external write-protect logic. |
| Dedicated ID Memory | 64 bytes at 7FC0H–7FFFH (accessed with A9 = 12 V) allow unique device serialization or firmware version tracking. |
Applications
| Industrial PLC Configuration Storage | Medical Device Calibration Data |
|---|---|
Use Scenario: Storing field-adjustable calibration coefficients and sensor offset values in programmable logic controllers operating in harsh factory environments. IC Role / Device Role / Timing Role: Nonvolatile configuration memory interfaced directly to an 8-bit microcontroller's data/address bus with SRAM-compatible timing. Use Value: Ensures parameter persistence across power cycles and supports field recalibration without firmware reflash; 10,000-cycle endurance accommodates periodic maintenance updates. |
Use Scenario: Retaining patient-specific therapy settings and device serial traceability in portable diagnostic equipment with strict regulatory data integrity requirements. IC Role / Device Role / Timing Role: Secure, low-power configuration store accessed during boot and runtime; software data protection prevents corruption during brown-out conditions. Use Value: 20 µA standby current extends battery life; 10-year data retention meets FDA-mandated record-keeping duration; dedicated ID memory supports UDI compliance. |
| Automotive ECU Parameter Tables | Telecom Line Card Firmware Patch Storage |
Use Scenario: Holding adaptive engine control parameters (e.g., fuel trim maps) updated during vehicle service or over-the-air reprogramming. IC Role / Device Role / Timing Role: Parallel EEPROM mapped into microcontroller memory space; accessed via CE/OE/WE control with 250 ns read timing matching MCU wait-state requirements. Use Value: Industrial temperature rating (−40°C to +85°C) ensures operation under hood conditions; page write minimizes update time during service mode. |
Use Scenario: Storing hot-swappable firmware patches for carrier-grade line cards where main flash is locked during operation. IC Role / Device Role / Timing Role: Standalone configuration and patch memory with independent bus interface, isolated from primary boot flash. Use Value: JEDEC pinout enables reuse of existing socket footprint; 3.3 V compatibility aligns with telecom board power architecture; DATA polling simplifies host driver development. |
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, 200 ns access, 2.7–3.6 V supply, 100 µA standby current, no software data protection. | Lacks SDP and Toggle Bit; requires external hardware write protection; higher standby current reduces suitability for battery-powered use. | Select when lowest-cost 250 ns-grade EEPROM is prioritized and system-level write protection is already implemented. |
| Microchip 25LC256-I/P | 256 Kbit SPI EEPROM, 3.3 V, 5 ms write cycle, 1 mA active current, 1 µA standby, no parallel interface. | Serial interface only; incompatible pinout and protocol; requires SPI controller and software driver changes. | Choose only if board redesign permits SPI migration and lower pin count justifies interface change. |
Compared with ST M28W256FCT and Microchip 25LC256-I/P, the AT28LV256-25TI uniquely combines JEDEC-compliant parallel interface, industrial temperature support, sub-100 µA standby, and integrated software/hardware write protection-making it optimal for drop-in upgrades of legacy 27C256-based systems requiring enhanced reliability.
Availability
AT28LV256-25TI is available at Aetrix Electronics and suitable for industrial automation, medical diagnostics, automotive control units, and telecom infrastructure requiring stable component supply, long-lifecycle support, and guaranteed traceable sourcing.
Supply support for AT28LV256-25TI 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 embedded systems.
The AT28LV256 product line was designed for reliable, low-voltage parallel EEPROM replacement in legacy SRAM/EPROM-based designs-emphasizing pin compatibility, simplified interface, and robust data integrity features.
FAQ
What is the maximum operating temperature range for the AT28LV256-25TI?
The AT28LV256-25TI is rated for industrial temperature operation from −40°C to +85°C. This specification is confirmed in the "DC and AC Operating Range" table of the official Atmel datasheet (Rev. 2400AX), where the "TI" suffix explicitly denotes the industrial temperature grade. The device maintains full functionality-including 250 ns read access and 10 ms page write-across this entire range.
Does the AT28LV256-25TI require external high voltage for programming?
No, the AT28LV256-25TI operates with a single 3.0–3.6 V supply for all read and write operations. High voltage (12 V ± 0.5 V on A9) is required only for accessing the dedicated 64-byte device identification memory at addresses 7FC0H–7FFFH-not for normal program/erase functions. Standard byte and page writes use only VCC.
How does software data protection work on the AT28LV256-25TI?
The AT28LV256-25TI implements software data protection (SDP) via a mandatory three-byte unlock sequence: write 0xAA to address 5555H, then 0x55 to 2AAAH, then 0xA0 to 5555H. Only after this sequence is completed can subsequent byte or page writes proceed. Without it, write attempts trigger internal timers but do not alter memory contents.
Can the AT28LV256-25TI be used as a direct replacement for the AT28C256?
No-the AT28C256 requires 5 V operation and has different timing and protection schemes. The AT28LV256-25TI is a low-voltage (3.0–3.6 V) device with distinct DC/AC characteristics, including lower standby current (20 µA vs. ~200 µA) and slower access (250 ns vs. 200 ns for -20 variant). While pinout is JEDEC-compatible, voltage domain mismatch makes direct substitution unsafe without system-level validation.
What package type is used for the AT28LV256-25TI?
The AT28LV256-25TI uses the 28-lead Plastic Thin Small Outline Package (TSOP), designated as "28T" in Atmel's ordering information. Its dimensions conform to JEDEC MO-153, with 0.55 mm lead pitch, gull-wing leads, and body size of 11.8 × 10.0 mm. Pin 1 is identified by a beveled corner or notch on the package top surface.
AT28LV256-25TI 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:
- -40°C ~ 85°C (TC)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 28-TSOP
AT28LV256-25TI FAQ
1.How can I place an order for AT28LV256-25TI through Aetrix?
Please submit a Request for Quotation (RFQ) for AT28LV256-25TI 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 AT28LV256-25TI reliable?
The price and inventory of AT28LV256-25TI are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for AT28LV256-25TI is usually 5 days.
3.What payment methods are accepted for AT28LV256-25TI?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for AT28LV256-25TI transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for AT28LV256-25TI?
AT28LV256-25TI orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your AT28LV256-25TI 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 AT28LV256-25TI?
For technical support, including AT28LV256-25TI datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your AT28LV256-25TI requirements.
6.How does Aetrix verify that AT28LV256-25TI is sourced from the original manufacturer or authorized distributors?
All AT28LV256-25TI 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 AT28LV256-25TI meets industry standards.
7.What is the process for return or replacement of AT28LV256-25TI?
All AT28LV256-25TI units undergo pre-shipment inspection (PSI). If there is an issue with AT28LV256-25TI, 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 AT28LV256-25TI part is unused and in its original packaging.
Return procedure for AT28LV256-25TI:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
AT28LV256-25TI Tags
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