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Microchip Technology AT29C256-15TI
- Part No.:
- AT29C256-15TI
- Manufacturer:
- Microchip Technology
- Category:
- Memory
- Package:
- 28-TSSOP (0.465", 11.80mm Width)
- Datasheet:
-
AT29C256-15TI.pdf
- Description:
- IC FLASH 256KBIT PARALLEL 28TSOP
- Quantity:
- Payment:
- Shipping:
Inventory:3,458
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Product details
Overview
AT29C256-15TI from Atmel is a 256 Kbit (32K × 8) 5V-only Flash memory IC used for nonvolatile program/data storage in embedded microcontroller systems, industrial controllers, and legacy BIOS modules. It delivers 150 ns read access time, supports page programming of 64-byte blocks, and operates across –40°C to +85°C with CMOS/TTL-compatible I/O.
For engineers reviewing the AT29C256-15TI datasheet, AT29C256-15TI pinout, AT29C256-15TI application, or AT29C256-15TI equivalent, key selection criteria include industrial temperature support, 5V-only reprogramming compatibility, software/hardware data protection, DATA polling and toggle-bit programming status detection, and PLCC/TSOP/PDIP package availability.
Technical Context
The AT29C256-15TI implements a page-based Flash architecture where 64-byte pages are loaded via byte-load cycles before internal erase-and-program execution. Its control logic uses CE/OE/WE three-line protocol identical to SRAM read timing, enabling drop-in replacement in existing 8-bit bus designs without address latching or external timing logic.
Programming relies on software command sequences (e.g., 5555h/2AAAh/A0h) for page write enable and chip erase, while hardware protection enforces VCC sense (≥3.8 V), 5 ms power-on delay, and noise filtering (<15 ns pulses rejected). Data integrity is verified via I/O7 DATA polling or I/O6 toggle-bit monitoring during write cycles.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Memory Size | 256 Kbit (32,768 × 8) - supports full firmware image storage for 8-bit MCUs with no external address multiplexing required |
| Read Access Time | 150 ns - meets timing for 6 MHz Z80/8051 bus interfaces without wait states |
| Page Program Time | 10 ms per 64-byte page - enables fast field updates without full-chip erase overhead |
| VCC Supply | 5 V ±10% - eliminates need for dedicated programming voltage rails or charge pumps |
| Endurance | >10,000 write/erase cycles - suitable for configuration storage with infrequent field updates |
| Standby Current | 300 µA (CMOS) - enables low-power retention in battery-backed systems |
| Operating Temperature | –40°C to +85°C - qualified for industrial control, automotive body electronics, and telecom infrastructure |
Pinout & Package
AT29C256-15TI is available in 28-pin TSOP (28T), 28-pin PDIP (28P6), and 32-pin PLCC (32J) packages. The TSOP variant (28T) is the standard industrial-grade package for this speed grade, featuring 8 mm × 13.4 mm footprint and gull-wing leads.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| A0–A14 | Address Inputs | 15-bit address bus supporting full 32K-word addressing; A0–A5 select byte within 64-byte page during programming |
| I/O0–I/O7 | Bidirectional Data Bus | 8-bit parallel interface; I/O7 provides DATA polling output; I/O6 provides toggle-bit status during programming |
| CE | Chip Enable | Active-low chip select; must be low for read, program, or erase; high-Z output when high |
| OE | Output Enable | Active-low output control; used with CE to prevent bus contention; must be high during programming |
| WE | Write Enable | Active-low write strobe; initiates byte load and page programming; low pulse width ≥90 ns required |
| VCC | Power Supply | +5 V ±10% main supply; powers core logic and I/O buffers; VCC sense circuit disables programming if <3.8 V |
| GND | Ground | Reference for all signals and power; decoupling capacitor required near VCC pin |
Key Features
| Feature | Design Value |
|---|---|
| 5V-only reprogramming | Eliminates need for 12 V programming supplies or external voltage translators in system design |
| Page programming (64 bytes) | Reduces update latency vs. full-chip erase; allows partial firmware patching without erasing valid sectors |
| Hardware data protection | VCC sense, 5 ms power-on delay, and noise filtering prevent spurious writes during brown-out or EMI events |
| Software data protection | Three-byte unlock sequence (5555h/2AAAh/A0h) prevents accidental writes; remains active across power cycles |
| DATA polling & toggle-bit | Enables real-time program completion detection without external timers or status registers |
Applications
| Industrial PLC Firmware Storage | Legacy PC BIOS Modules |
|---|---|
Use Scenario: Storing ladder logic firmware and I/O configuration tables in programmable logic controllers deployed in factory automation environments. IC Role / Device Role / Timing Role: Nonvolatile code storage with direct 8-bit bus interface; replaces EPROMs requiring UV erasure and socketed programming. Use Value: Enables field firmware upgrades via serial port without removing the module; 150 ns access ensures deterministic scan-cycle timing in real-time control loops. |
Use Scenario: Holding boot firmware and hardware initialization routines in desktop motherboards and embedded x86 systems from the late 1990s–early 2000s. IC Role / Device Role / Timing Role: Primary BIOS ROM replacement; directly mapped into CPU memory space at 0xE0000–0xFFFFF with SRAM-like read timing. Use Value: Eliminates need for external programming hardware during manufacturing; software-controlled erase/program allows BIOS updates via floppy or flash utility. |
| Telecom Line Card Configuration | Medical Device Calibration Data |
Use Scenario: Storing line provisioning parameters, DSP coefficients, and fault logging history in T1/E1 interface cards operating in central office environments. IC Role / Device Role / Timing Role: Configuration memory accessed during card power-up and runtime diagnostics; supports hot-swap initialization sequences. Use Value: Industrial temperature range (–40°C to +85°C) ensures reliability in uncontrolled telecom cabinets; hardware write protection prevents corruption during power transients. |
Use Scenario: Retaining sensor calibration constants, user preferences, and audit trail logs in portable diagnostic equipment such as infusion pumps and ECG monitors. IC Role / Device Role / Timing Role: Secure parameter storage with dual-layer protection (hardware VCC sense + software unlock) meeting IEC 62304 safety requirements. Use Value: 300 µA standby current extends battery life in portable units; >10,000 endurance cycles support lifetime recalibration without memory wear-out concerns. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar Flash memory applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| AM29LV256M-150EC | 3.3 V core with 5 V I/O tolerance; 150 ns access; 1 Mbit density; requires VPP = 12 V for sector erase | Designed for mixed-voltage 3.3 V systems; not 5 V-only compatible | Select only if migrating to lower-voltage platforms with voltage translation; not a direct replacement |
| SST39VF256A-70-4C-NHE | 3.3 V supply; 70 ns access; 256 Kbit; supports byte/word programming; no hardware VCC sense | Optimized for faster read performance in 3.3 V embedded systems; lacks industrial-temp 5 V-only operation | Choose for new 3.3 V designs requiring sub-100 ns access; requires redesign for VCC and protection logic |
Compared with AM29LV256M-150EC and SST39VF256A-70-4C-NHE, the AT29C256-15TI uniquely supports true 5 V-only operation with integrated hardware write protection and industrial temperature range-making it the only option for legacy 5 V controller upgrades where voltage rail changes or PCB rework are prohibited.
Availability
AT29C256-15TI is available at Aetrix Electronics and suitable for industrial PLC firmware storage, legacy PC BIOS modules, and telecom line card configuration requiring stable component supply across extended temperature ranges and long production lifecycles.
Supply support for AT29C256-15TI 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 AT29C256 product line was designed to replace UV-erasable EPROMs in 5 V embedded systems, delivering in-system reprogrammability without high-voltage programming hardware or socketed devices.
FAQ
What is the maximum operating temperature range for the AT29C256-15TI?
The AT29C256-15TI is rated for industrial temperature operation from –40°C to +85°C. This specification is confirmed in the Ordering Information table of the official datasheet (Rev. 0046O–FLASH–06/02), where the "TI" suffix explicitly denotes the industrial temperature grade. The device maintains full functionality-including 150 ns read access, 10 ms page programming, and hardware data protection-across this full range.
Does the AT29C256-15TI require a high-voltage programming signal like older EPROMs?
No, the AT29C256-15TI does not require any high-voltage programming signal. It operates with a single 5 V ±10% supply for both read and reprogram functions. Programming is initiated using standard 5 V logic-level commands (e.g., 5555h/2AAAh/A0h) applied to the address and data bus-no external VPP generator or 12 V rail is needed. This is a defining feature of the AT29C256-15TI's 5V-only Flash architecture.
How is programming completion detected on the AT29C256-15TI?
Programming completion on the AT29C256-15TI is detected using either DATA polling on I/O7 or the toggle-bit method on I/O6. During programming, reading the last loaded byte returns the complement of the data on I/O7; when complete, true data appears. Alternatively, I/O6 toggles between 0 and 1 until programming finishes, then stabilizes. Both methods are fully supported in the AT29C256-15TI and require no external components.
Can the AT29C256-15TI be used as a direct replacement for a 27C256 EPROM?
Yes, the AT29C256-15TI is pin-compatible and functionally compatible with the 27C256 EPROM in read mode, sharing identical 28-pin DIP/TSOP pinouts, address/data bus mapping, and CE/OE/WE control. However, unlike the 27C256, the AT29C256-15TI supports in-system reprogramming via software commands and requires no UV erasure-making it a true drop-in upgrade for existing 27C256 sockets in 5 V systems.
What package types are offered for the AT29C256-15TI?
The AT29C256-15TI is offered in three package types: 28-pin Plastic Dual Inline Package (PDIP, code 28P6), 28-pin Plastic Thin Small Outline Package (TSOP, code 28T), and 32-pin Plastic Leaded Chip Carrier (PLCC, code 32J). All variants carry the "TI" suffix and meet the same industrial temperature and electrical specifications. The TSOP (28T) is the most commonly stocked surface-mount option for modern PCB assembly.
AT29C256-15TI 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:
- FLASH
- Technology:
- FLASH
- 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:
- 28-TSOP
AT29C256-15TI FAQ
1.How can I place an order for AT29C256-15TI through Aetrix?
Please submit a Request for Quotation (RFQ) for AT29C256-15TI 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 AT29C256-15TI reliable?
The price and inventory of AT29C256-15TI are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for AT29C256-15TI is usually 5 days.
3.What payment methods are accepted for AT29C256-15TI?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for AT29C256-15TI transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for AT29C256-15TI?
AT29C256-15TI orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your AT29C256-15TI 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 AT29C256-15TI?
For technical support, including AT29C256-15TI datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your AT29C256-15TI requirements.
6.How does Aetrix verify that AT29C256-15TI is sourced from the original manufacturer or authorized distributors?
All AT29C256-15TI 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 AT29C256-15TI meets industry standards.
7.What is the process for return or replacement of AT29C256-15TI?
All AT29C256-15TI units undergo pre-shipment inspection (PSI). If there is an issue with AT29C256-15TI, 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 AT29C256-15TI part is unused and in its original packaging.
Return procedure for AT29C256-15TI:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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