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Microchip Technology AT29C256-12TI-T
- Part No.:
- AT29C256-12TI-T
- Manufacturer:
- Microchip Technology
- Category:
- Memory
- Package:
- 32-TFSOP (0.724", 18.40mm Width)
- Datasheet:
-
AT29C256-12TI-T.pdf
- Description:
- IC FLASH 256KBIT PARALLEL 32TSOP
- Quantity:
- Payment:
- Shipping:
Inventory:1,433
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Product details
Overview
AT29C256-12TI-T 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 applications. It delivers 120 ns read access time, supports page programming of 64 bytes in 10 ms, and operates across –40°C to +85°C with CMOS/TTL-compatible I/O.
For engineers reviewing the AT29C256-12TI-T datasheet, AT29C256-12TI-T pinout, AT29C256-12TI-T application, or AT29C256-12TI-T 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 legacy 28-pin TSOP footprint designs.
Technical Context
The AT29C256-12TI-T 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 responds to CE/OE/WE timing sequences aligned with JEDEC-standard AC waveforms, enabling static RAM–like read behavior and deterministic write-cycle timing.
It integrates dual data protection: hardware-level VCC sensing (inhibits programming below 3.8 V), noise filtering on WE/CE inputs (<15 ns pulses ignored), and software-controlled lockout requiring three-step command sequences (e.g., 5555h/2AAAh/A0h) to enable or disable writes - all verified per Atmel's 0046O–FLASH–06/02 specification.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Memory Size | 256 Kbit (32,768 × 8), directly addressable as 15-bit address space (A0–A14) |
| Read Access Time | 120 ns max - defines minimum bus cycle duration for reliable read operations |
| Page Program Time | 10 ms typical - fixed internal timer governs full 64-byte page write after load completion |
| VCC Supply | 5 V ±10% - eliminates need for high-voltage programming supplies; compatible with standard logic rails |
| Operating Temperature | –40°C to +85°C - qualified for industrial-grade embedded environments without derating |
| Endurance | >10,000 program/erase cycles per sector - enables field-upgradable firmware storage |
| Standby Current | 300 µA typical (CMOS mode) - critical for low-power sleep states in battery-backed systems |
Pinout & Package
AT29C256-12TI-T is packaged in a 28-lead Plastic Thin Small Outline Package (TSOP, Type I, package code 28T), 8 mm × 13.4 mm body, 0.55 mm lead pitch, compliant with JEDEC MO-183. Pin 1 identifier located at top-left corner with beveled edge marking.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| A0–A14 | Address Inputs | 15-bit address bus; A0–A5 select byte within 64-byte page, A6–A14 select page |
| I/O0–I/O7 | Bidirectional Data Bus | 8-bit parallel interface; supports DATA polling on I/O7 and toggle-bit detection on I/O6 |
| CE | Chip Enable | Active-low chip select; must be low during read, program, or erase; inhibits writes when high |
| OE | Output Enable | Active-low output control; high-Z state when high; required high during programming |
| WE | Write Enable | Active-low write strobe; controls byte-load latching and initiates internal program cycle |
| VCC | Power Supply | +5 V ±10% supply; powers core and I/O; VCC sense circuit disables programming if <3.8 V |
| GND | Ground Reference | Signal and power return; decoupling capacitor placement critical near pin 14 per layout guidelines |
Key Features
| Feature | Design Value |
|---|---|
| 5V-only reprogramming | Eliminates need for external 12 V programming voltage - simplifies power design and reduces BOM count |
| Page-based 64-byte programming | Reduces firmware update latency vs. full-chip erase; enables partial-field updates without erasing unrelated sectors |
| DATA polling & toggle-bit status | Enables real-time, non-blocking program completion detection using standard I/O pins - no external timers required |
| Hardware + software data protection | Prevents accidental writes during power-up/down or noise events; software lock requires authenticated command sequence |
| CMOS standby current <300 µA | Supports ultra-low-power retention modes in portable or energy-harvesting systems |
Applications
| Industrial PLC Firmware Storage | Embedded Bootloader Memory |
|---|---|
|
Use Scenario: Storing firmware images and configuration parameters in programmable logic controllers deployed in factory automation environments. IC Role / Device Role / Timing Role: Nonvolatile storage for boot code and runtime configuration; accessed during cold start and field updates. Use Value: 120 ns read speed ensures fast boot initialization; industrial temperature rating (–40°C to +85°C) guarantees reliability in uncontrolled cabinet environments. |
Use Scenario: Holding bootloader code for microcontrollers in medical devices requiring secure, field-upgradable firmware. IC Role / Device Role / Timing Role: Primary boot memory mapped into MCU address space; programmed via in-system interface during manufacturing or service. Use Value: Software data protection prevents unauthorized firmware modification; >10,000 endurance cycles support repeated calibration updates over product lifetime. |
| Legacy Industrial Instrumentation | Communications Equipment Configuration |
|
Use Scenario: Retaining calibration tables and sensor compensation coefficients in analog signal conditioning modules. IC Role / Device Role / Timing Role: Static memory replacement for EPROM sockets; retains data without battery backup. Use Value: Pin-compatible with industry-standard 28-pin TSOP footprint; 5V-only operation avoids redesign of existing 5V power distribution networks. |
Use Scenario: Storing protocol stack configuration, MAC addresses, and feature-enable bits in network interface cards and modems. IC Role / Device Role / Timing Role: Configuration store accessed at power-on and during hot-plug reinitialization sequences. Use Value: DATA polling on I/O7 allows host processor to synchronize firmware updates without fixed delays; low 300 µA standby current minimizes idle power draw. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar Flash memory applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| AM29LV256M-120EC | 3.3 V core with 5 V tolerant I/O; 120 ns read; 100 µA standby; no software data protection | Requires level-shifting or dual-supply design; lacks built-in write-lock algorithm | Preferred where lower power and modern 3.3 V infrastructure exist; not drop-in for 5 V-only systems |
| SST39VF256A-120-4C-EKE | 3.3 V supply; 120 ns read; 20 µA standby; supports byte-write (not page-only); no hardware VCC sense | Enables single-byte updates but lacks robust power-fail write inhibition | Best for new 3.3 V designs needing granular writes; unsuitable as direct replacement due to voltage and protection mismatch |
Compared with AM29LV256M-120EC and SST39VF256A-120-4C-EKE, the AT29C256-12TI-T uniquely combines 5V-only operation, hardware VCC-sense lockout, and authenticated software protection - making it the only option among the three qualified for legacy industrial systems where voltage stability and write safety are non-negotiable.
Availability
AT29C256-12TI-T is available at Aetrix Electronics and suitable for industrial PLC firmware storage, embedded bootloader memory, and legacy instrumentation requiring stable component supply across extended lifecycle commitments.
Supply support for AT29C256-12TI-T 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 embedded applications.
The AT29C256 product line was designed for cost-sensitive, industrial-grade Flash memory replacement of EPROMs and EEPROMs in systems requiring in-system reprogrammability without high-voltage programming infrastructure.
FAQ
What is the maximum operating temperature range for the AT29C256-12TI-T?
The AT29C256-12TI-T is rated for industrial temperature operation from –40°C to +85°C. This range is validated per the device's DC and AC specifications in Atmel's 0046O–FLASH–06/02 datasheet and applies specifically to the -TI suffix variant. The "T" denotes TSOP packaging, and "I" confirms industrial temperature qualification - distinct from commercial-grade (-C) versions.
Does the AT29C256-12TI-T require external high-voltage programming signals?
No, the AT29C256-12TI-T uses 5V-only reprogramming and does not require external high-voltage (e.g., 12 V) programming signals. All program and erase operations are initiated using standard 5 V logic levels applied to CE, OE, and WE pins in precise timing sequences defined in the datasheet. This eliminates the need for charge pumps or auxiliary voltage rails.
How is programming completion detected on the AT29C256-12TI-T?
Programming completion on the AT29C256-12TI-T is detected using either DATA polling on I/O7 (complement of written data toggles until completion) or the toggle-bit method on I/O6 (bit toggles during operation and stabilizes upon finish). Both methods are implemented in hardware and require no external components - enabling host software to poll status synchronously without fixed timeouts.
Can the AT29C256-12TI-T be used as a direct replacement for older EPROMs like the 27C256?
The AT29C256-12TI-T is pin-compatible with the 27C256 in 28-pin DIP and TSOP packages and shares identical address/data bus organization (32K × 8), but differs in control signaling: it uses WE instead of OE for write control and requires specific software command sequences for programming. While hardware socket replacement is possible, firmware must be updated to implement page-load and status-polling protocols - it is not a drop-in functional replacement.
What package type does the AT29C256-12TI-T use, and what are its key mechanical dimensions?
The AT29C256-12TI-T uses a 28-lead Plastic Thin Small Outline Package (TSOP, Type I), designated 28T per Atmel's ordering information. Its body measures 8.0 mm × 13.4 mm, with 0.55 mm lead pitch, 1.0 mm nominal height (A2), and JEDEC MO-183 compliance. Pin 1 is marked by a beveled corner, and the package is lead-free and RoHS-compliant per Atmel's 2002 specification.
AT29C256-12TI-T Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Microchip Technology
- Series:
- -
- Package/Case:
- 32-TFSOP (0.724", 18.40mm Width)
- Packaging:
- Tape & Reel (TR)
- 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:
- 120 ns
- Voltage - Supply:
- 4.5V ~ 5.5V
- Operating Temperature:
- -40°C ~ 85°C (TC)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 32-TSOP
AT29C256-12TI-T FAQ
1.How can I place an order for AT29C256-12TI-T through Aetrix?
Please submit a Request for Quotation (RFQ) for AT29C256-12TI-T 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 AT29C256-12TI-T reliable?
The price and inventory of AT29C256-12TI-T are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for AT29C256-12TI-T is usually 5 days.
3.What payment methods are accepted for AT29C256-12TI-T?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for AT29C256-12TI-T transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for AT29C256-12TI-T?
AT29C256-12TI-T orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your AT29C256-12TI-T 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 AT29C256-12TI-T?
For technical support, including AT29C256-12TI-T datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your AT29C256-12TI-T requirements.
6.How does Aetrix verify that AT29C256-12TI-T is sourced from the original manufacturer or authorized distributors?
All AT29C256-12TI-T 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 AT29C256-12TI-T meets industry standards.
7.What is the process for return or replacement of AT29C256-12TI-T?
All AT29C256-12TI-T units undergo pre-shipment inspection (PSI). If there is an issue with AT29C256-12TI-T, 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 AT29C256-12TI-T part is unused and in its original packaging.
Return procedure for AT29C256-12TI-T:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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