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Microchip Technology AT29C256-90TI
- Part No.:
- AT29C256-90TI
- Manufacturer:
- Microchip Technology
- Category:
- Memory
- Package:
- 28-TSSOP (0.465", 11.80mm Width)
- Datasheet:
-
AT29C256-90TI.pdf
- Description:
- IC FLASH 256KBIT PARALLEL 28TSOP
- Quantity:
- Payment:
- Shipping:
Inventory:4,640
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Product details
Overview
AT29C256-90TI 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 firmware boot code storage. It delivers 90 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 AT29C256-90TI datasheet, AT29C256-90TI pinout, AT29C256-90TI application, or AT29C256-90TI equivalent, key selection considerations include its 5V-only reprogramming architecture, hardware/software data protection, DATA polling and toggle-bit programming status detection, and compatibility with PLCC-32, PDIP-28, and TSOP-28 packages.
Technical Context
The AT29C256-90TI implements a page-based Flash architecture where 64-byte pages are erased and programmed in a single internal cycle using on-chip timing control. Its dual-line chip enable (CE) and output enable (OE) logic enables flexible bus interfacing without contention, while WE-controlled byte loading allows sequential or non-sequential data entry within a page window.
Hardware data protection includes VCC sense (<3.8 V inhibits programming), 5 ms power-on delay, noise filtering (<15 ns pulses rejected), and active-level inhibition (OE low / CE high / WE high blocks writes). Software protection uses a three-command sequence (AAh/55h/A0h) to enable/disable write locking per page.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Memory Size | 256 Kbit (32,768 × 8 bits); sufficient for full boot code or configuration tables in 8-bit MCU systems. |
| Read Access Time | 90 ns max; enables direct execution from Flash in systems with ≤11 MHz bus clocks. |
| Page Program Time | 10 ms typical; allows rapid field updates of firmware segments without full-chip erase overhead. |
| VCC Supply | 5 V ±10%; eliminates need for dedicated programming voltage rails in system design. |
| Endurance | >10,000 write/erase cycles per sector; supports long-term field firmware upgrades in industrial equipment. |
| Standby Current | 300 µA typical (CMOS mode); reduces power in sleep-mode applications like remote sensors. |
| Operating Temp | -40°C to +85°C; qualified for industrial control panels, motor drives, and outdoor instrumentation. |
Pinout & Package
AT29C256-90TI is available in three industry-standard packages: 32-lead PLCC (32J), 28-lead PDIP (28P6), and 28-lead TSOP Type I (28T). The PLCC variant features pins 1 and 17 marked "DON'T CONNECT", and all packages share identical pin functions and signal mapping.
| 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; latches input data during WE/CE pulse and drives output during valid read cycles. |
| CE | Chip Enable | Active-low global device select; must be low for read, program, or erase operations; enables multi-device bus sharing. |
| OE | Output Enable | Active-low output gate; high-Z state when high prevents bus contention during shared-memory access. |
| WE | Write Enable | Active-low control for byte load and page programming initiation; timing-critical for 150 µs inter-byte loading window. |
| VCC | Power Supply | +5 V ±10% main supply; powers core logic and I/O buffers; internally regulated for stable programming voltage. |
| GND | Ground Reference | Signal and power return path; decoupling capacitor required near VCC pin for noise immunity during programming. |
| NC / DC | No Connect / Don't Connect | Pins with no internal connection (e.g., PLCC pins 1, 17); must remain unconnected per datasheet to avoid malfunction. |
Key Features
| Feature | Design Value |
|---|---|
| 5V-only reprogramming | Eliminates need for external 12 V programming supplies - simplifies PCB layout and reduces BOM cost. |
| Internal program timer & control | Automates erase-before-program sequence and timing; removes requirement for external timing circuitry or software delays. |
| DATA polling (I/O7) | Enables real-time detection of programming completion via read-back of complemented data - no fixed timeout needed. |
| Toggle bit (I/O6) | Provides alternate, address-agnostic method to monitor programming/erase progress - useful in interrupt-driven systems. |
| Software data protection | Three-command lock/unlock sequence prevents accidental writes during power transitions or firmware bugs. |
| Hardware data protection | VCC sensing, noise filtering, and level-sensitive inhibit logic guard against spurious writes in electrically noisy environments. |
Applications
| Industrial PLC Firmware Storage | Embedded Boot Code Memory |
|---|---|
|
Use Scenario: Storing ladder logic firmware and I/O configuration in programmable logic controllers deployed in factory automation. IC Role / Device Role / Timing Role: Nonvolatile boot memory mapped to MCU address space; provides deterministic 90 ns read latency for fast startup and runtime instruction fetch. Use Value: >10,000 endurance cycles support frequent firmware updates during commissioning and maintenance without replacement. |
Use Scenario: Holding bootloader and application image for 8-bit microcontrollers in medical diagnostic devices requiring regulatory-compliant firmware integrity. IC Role / Device Role / Timing Role: Primary code storage device accessed at power-up; supports in-system reprogramming via UART/JTAG debug interface. Use Value: Hardware + software data protection ensures firmware remains uncorrupted during brown-out events or ESD transients. |
| Telecom Line Card Configuration | Automotive Body Control Module |
|
Use Scenario: Storing port-specific configuration parameters and calibration data for DSLAM line cards operating in telecom central offices. IC Role / Device Role / Timing Role: Parameter EEPROM replacement; accessed via parallel bus during initialization to configure PHY registers and DSP settings. Use Value: 300 µA standby current minimizes quiescent draw in always-on network infrastructure with thermal constraints. |
Use Scenario: Retaining door lock actuator calibration, lighting profiles, and CAN node configuration in automotive body control modules. IC Role / Device Role / Timing Role: Nonvolatile parameter store interfaced to 8051-class MCU; survives battery disconnect and meets AEC-Q100 temperature requirements. Use Value: -40°C to +85°C operation and VCC-sense programming inhibition ensure reliability in under-hood thermal cycling. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar Flash memory applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| MX29LV256EITI-90G | 3.0 V–3.6 V supply only; 90 ns read; 128-word page size; supports CFI query mode. | Requires separate 3.3 V rail; not drop-in compatible with 5 V systems using AT29C256-90TI. | Select when migrating to lower-voltage designs and CFI-based firmware update tools are available. |
| SST39VF256A-90-4C-EKE | 3.3 V supply; 90 ns read; 128-byte page; supports both software and hardware reset protection. | Not pin-compatible with AT29C256-90TI; requires PCB redesign due to different pinout and voltage domain. | Choose for new 3.3 V designs needing enhanced security features and JEDEC-standard command sets. |
Compared with MX29LV256EITI-90G and SST39VF256A-90-4C-EKE, the AT29C256-90TI offers unique 5V-only operation and legacy 64-byte page architecture ideal for maintaining existing industrial control hardware without voltage translation or layout changes.
Availability
AT29C256-90TI is available at Aetrix Electronics and suitable for industrial PLC firmware storage, embedded boot code memory, and telecom line card configuration requiring stable component supply and long-lifecycle support.
Supply support for AT29C256-90TI 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 U.S.-based semiconductor company specializing in microcontrollers, Flash memory, and secure authentication ICs.
The AT29C256 product line was designed for cost-sensitive, 5V-based embedded systems requiring reliable in-system reprogrammability without high-voltage programming infrastructure.
FAQ
What is the maximum operating temperature range for the AT29C256-90TI?
The AT29C256-90TI is rated for industrial temperature operation from -40°C to +85°C. This specification is confirmed in the Ordering Information table and DC Operating Range section of the official Atmel datasheet (Rev. 0046O–FLASH–06/02), making it suitable for deployment in harsh environments such as factory floors and outdoor telecom cabinets. The AT29C256-90TI maintains full functionality-including 90 ns read timing and 10 ms page programming-across this full range.
Does the AT29C256-90TI require a high-voltage programming supply?
No, the AT29C256-90TI does not require a high-voltage programming supply. It is a 5V-only Flash memory: all programming, erasing, and reading operations use a single +5 V ±10% supply. This is explicitly stated in the Features section and reinforced by hardware protection mechanisms like VCC sense (programming inhibited below ~3.8 V). The AT29C256-90TI eliminates the need for external 12 V generators or charge pumps found in older EPROM/EEPROM devices.
How is programming completion detected on the AT29C256-90TI?
Programming completion on the AT29C256-90TI can be detected using either DATA polling on I/O7 or the Toggle Bit on I/O6. During programming, reading the last loaded byte returns its complement on I/O7; when true data appears, programming is complete. Alternatively, I/O6 toggles between 0 and 1 during active programming and stabilizes once finished. Both methods are documented in the Device Operation section and require no external timing components - the AT29C256-90TI handles all internal timing autonomously.
Is the AT29C256-90TI pin-compatible with other package variants of the same part number?
Yes, the AT29C256-90TI (TSOP-28) shares identical pin functions and signal definitions with the AT29C256-90JC (PLCC-32) and AT29C256-90PC (PDIP-28), as confirmed in the Pin Configurations and Ordering Information sections. However, physical pin count and layout differ: PLCC-32 has two additional NC pins (1 and 17), while PDIP-28 and TSOP-28 use the same 28-pin mapping. Board-level interchangeability requires matching package footprint and voltage compliance - the AT29C256-90TI is not mechanically interchangeable with PLCC variants without PCB redesign.
What data protection mechanisms does the AT29C256-90TI support?
The AT29C256-90TI supports dual-layer data protection: hardware-level features (VCC sense, 5 ms power-on delay, noise filtering, and level-sensitive inhibit logic) and software-level protection via a three-command sequence (AAh → 55h → A0h to enable; AAh → 55h → 80h → AAh → 55h → 20h to disable). These mechanisms are fully documented in the Hardware and Software Data Protection sections and apply identically across all AT29C256-90TI units regardless of batch or date code.
AT29C256-90TI 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:
- 90 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
AT29C256-90TI FAQ
1.How can I place an order for AT29C256-90TI through Aetrix?
Please submit a Request for Quotation (RFQ) for AT29C256-90TI 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 AT29C256-90TI reliable?
The price and inventory of AT29C256-90TI are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for AT29C256-90TI is usually 5 days.
3.What payment methods are accepted for AT29C256-90TI?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for AT29C256-90TI transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for AT29C256-90TI?
AT29C256-90TI orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your AT29C256-90TI 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 AT29C256-90TI?
For technical support, including AT29C256-90TI datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your AT29C256-90TI requirements.
6.How does Aetrix verify that AT29C256-90TI is sourced from the original manufacturer or authorized distributors?
All AT29C256-90TI 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 AT29C256-90TI meets industry standards.
7.What is the process for return or replacement of AT29C256-90TI?
All AT29C256-90TI units undergo pre-shipment inspection (PSI). If there is an issue with AT29C256-90TI, 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 AT29C256-90TI part is unused and in its original packaging.
Return procedure for AT29C256-90TI:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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