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Microchip Technology AT29C256-12TI
- Part No.:
- AT29C256-12TI
- Manufacturer:
- Microchip Technology
- Category:
- Memory
- Package:
- 28-TSSOP (0.465", 11.80mm Width)
- Datasheet:
-
AT29C256-12TI.pdf
- Description:
- IC FLASH 256KBIT PARALLEL 28TSOP
- Quantity:
- Payment:
- Shipping:
Inventory:3,127
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Product details
Overview
AT29C256-12TI from Atmel is a 256 Kbit (32K × 8) 5V-only Flash memory IC used for nonvolatile program/data storage in embedded control and firmware applications. It delivers 120 ns read access time, supports page programming of 64-byte blocks in 10 ms, and operates across -40°C to +85°C industrial temperature range with CMOS/TTL-compatible I/O.
For engineers reviewing the AT29C256-12TI datasheet, AT29C256-12TI pinout, AT29C256-12TI application, or AT29C256-12TI equivalent, key selection criteria 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 AT29C256-12TI implements a page-based Flash architecture where 64-byte pages are loaded via byte-load cycles before internal erase-and-program execution. Its dual-line chip enable (CE) and output enable (OE) control enables bus contention avoidance during mixed read/write operations in microcontroller systems.
Hardware data protection includes VCC sense (<3.8 V inhibits programming), 5 ms power-on delay, and noise filtering on WE/CE inputs. Software data protection uses a three-command sequence (AAh/55h/A0h) to enable/disable write access, preserving state across power cycles without reset.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Memory Size | 256 Kbit (32,768 × 8), sufficient for boot code or configuration tables in 8-bit microcontroller systems |
| Read Access Time | 120 ns maximum - meets timing requirements for 8 MHz Z80 or 6502-based systems with no wait states |
| Page Program Time | 10 ms per 64-byte page - enables rapid field updates without full-chip erasure |
| VCC Supply | 5 V ± 10% - eliminates need for dedicated programming voltage rails in system design |
| Endurance | ≥10,000 write/erase cycles per sector - supports firmware update cycles over 5+ years in industrial logging devices |
| Standby Current | 300 µA CMOS - enables low-power operation in battery-backed or energy-constrained edge nodes |
| Operating Temp | -40°C to +85°C - qualified for industrial control panels, motor drives, and outdoor instrumentation |
Pinout & Package
AT29C256-12TI is available in PLCC-32, PDIP-28, and TSOP-28 packages. The industrial-grade variant AT29C256-12TI uses the TSOP-28 package (8 mm × 13.4 mm, 0.55 mm pitch), with pins 1–14 and 15–28 arranged in two rows. Pins 1 and 17 in PLCC are NC; all TSOP and PDIP variants have identical pin functions.
| 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 feedback; I/O6 toggles during programming/erase |
| CE | Chip Enable | Active-low global enable; must be low for read, program, or erase; high disables outputs and reduces current to 300 µA |
| OE | Output Enable | Active-low read control; used with CE to manage bus contention; high during programming to isolate outputs |
| WE | Write Enable | Active-low control for byte loading and page programming initiation; synchronized with CE for timing compliance |
| VCC | Power Supply | +5 V ± 10% main supply; powers core logic and I/O drivers; internally regulated for stable programming voltage |
| GND | Ground Reference | Signal and power return; decoupling capacitor required at VCC pin per datasheet layout guidelines |
Key Features
| Feature | Design Value |
|---|---|
| 5V-only reprogramming | Eliminates need for external 12 V programming supply - simplifies PCB layout and reduces BOM count |
| Page programming (64 bytes) | Reduces firmware update time by >95% vs. full-chip erase; enables partial-field upgrades without data loss |
| DATA polling on I/O7 | Allows real-time program completion detection without timer overhead or interrupt latency in host MCU firmware |
| Toggle-bit status on I/O6 | Provides asynchronous, hardware-based verification of programming/erase progress independent of address location |
| Hardware + software data protection | Prevents accidental writes during power-up/down or noise events - critical for unattended industrial deployments |
Applications
| Industrial PLC Firmware Storage | Medical Device Configuration Memory |
|---|---|
|
Use Scenario: Storing ladder logic programs and I/O mapping tables in programmable logic controllers deployed in factory automation environments. IC Role / Device Role / Timing Role: Nonvolatile program memory interfaced directly to 8051 or Z80 microcontrollers; provides 120 ns read access to support deterministic scan-cycle timing. Use Value: Enables field-upgradable firmware without requiring specialized programmers; 10,000-cycle endurance supports >10 years of scheduled maintenance updates. |
Use Scenario: Retaining calibration coefficients, patient history logs, and safety-critical device settings in portable diagnostic equipment operating under battery power. IC Role / Device Role / Timing Role: Low-power configuration store accessed only during boot or user-initiated recalibration; standby current of 300 µA extends battery life between charges. Use Value: Hardware data protection prevents corruption during brown-out conditions; software lock ensures regulatory-compliant write authorization protocols. |
| Automotive Body Control Module | Legacy Industrial HMI Display |
|
Use Scenario: Holding lighting control algorithms and door-lock actuation sequences in automotive body electronics modules exposed to wide thermal cycling. IC Role / Device Role / Timing Role: Firmware ROM mapped into microcontroller address space; operates reliably from -40°C to +85°C without derating. Use Value: TSOP-28 package enables compact placement near MCU; 5V-only operation avoids voltage translation circuitry in 5V-centric legacy architectures. |
Use Scenario: Serving as boot ROM for monochrome LCD controllers in factory-floor HMIs running proprietary display firmware. IC Role / Device Role / Timing Role: Static RAM-compatible interface allows drop-in replacement of obsolete EPROMs without modifying existing 8-bit bus timing logic. Use Value: 120 ns access time matches original EPROM specs; pinout compatibility with 27C256 simplifies board-level redesign and qualification. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar Flash memory applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SST39SF256-120-4C-NHE | 4 Mbit capacity, 120 ns access, 3.3 V core with 5 V tolerant I/O; requires VPP = 12 V for programming | Higher density but incompatible voltage architecture; not suitable for pure 5 V systems without level shifting | Select only if migrating to 3.3 V domain and requiring >256 Kbit storage |
| MX29LV256EITXGI-12G | 3 V supply, 120 ns access, 256 Mbit density; supports CFI command set and sector protection | Not pin-compatible; requires different initialization sequence and lacks DATA polling on I/O7 | Choose for new 3 V designs needing higher density and JEDEC-standardized interface |
Compared with SST39SF256-120-4C-NHE and MX29LV256EITXGI-12G, the AT29C256-12TI uniquely supports true 5 V-only operation with integrated hardware/software write protection and industry-standard DATA polling - making it the only viable option for maintaining legacy 5 V microcontroller systems without redesigning power or interface circuitry.
Availability
AT29C256-12TI is available at Aetrix Electronics and suitable for industrial control panels, medical diagnostics equipment, and automotive body electronics requiring stable component supply across extended product lifecycles.
Supply support for AT29C256-12TI 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 semiconductor manufacturer specializing in microcontrollers, Flash memory, and secure authentication ICs for embedded systems.
The AT29C256 product line was designed for in-system programmable nonvolatile storage in 8-bit microcontroller-based applications where 5 V operation, industrial temperature tolerance, and simple firmware update capability are essential.
FAQ
What is the maximum read access time specified for the AT29C256-12TI?
The AT29C256-12TI has a maximum read access time of 120 ns, as confirmed by its ordering code suffix "-12". This value is guaranteed across the full industrial temperature range (-40°C to +85°C) and 5 V ± 10% supply, enabling direct interface with 8 MHz Z80, 6502, or 8051 microcontrollers without wait-state insertion. The AT29C256-12TI achieves this performance using Atmel's advanced nonvolatile CMOS process.
Does the AT29C256-12TI require a high-voltage programming supply?
No, the AT29C256-12TI operates with 5 V ± 10% only for both read and programming functions - no external 12 V VPP supply is needed. Programming is initiated using standard 5 V logic levels applied to WE and CE, with internal charge pumps generating necessary voltages. This eliminates high-voltage routing on PCBs and simplifies system-level design compared to older EPROM or EEPROM alternatives. The AT29C256-12TI maintains this 5V-only capability across all supported packages and temperature grades.
How does the AT29C256-12TI indicate completion of a page programming cycle?
The AT29C256-12TI provides two hardware methods: DATA polling on I/O7 and toggle-bit detection on I/O6. During programming, reading the last loaded byte returns the complement of data on I/O7; when programming completes, true data appears. Simultaneously, I/O6 toggles between 0 and 1 until completion, then stabilizes. Both mechanisms allow the host microcontroller to detect completion without fixed delays. These features are intrinsic to the AT29C256-12TI's architecture and do not require external components or firmware timers.
What package types are offered for the AT29C256-12TI?
The AT29C256-12TI is specifically packaged in the 28-lead Plastic Thin Small Outline Package (TSOP, type I, package code 28T), measuring 8 mm × 13.4 mm with 0.55 mm lead pitch. While the AT29C256 family also includes PLCC-32 and PDIP-28 variants, the "-TI" suffix denotes the industrial-grade TSOP version. Pin functions are identical across packages, but mechanical dimensions, thermal characteristics, and board assembly requirements differ - the AT29C256-12TI's TSOP form factor supports high-density surface-mount layouts in space-constrained industrial modules.
Can the AT29C256-12TI be used as a direct replacement for the AT29C256-12JI?
No - the AT29C256-12TI and AT29C256-12JI share identical electrical specifications and timing but differ in packaging: AT29C256-12TI uses TSOP-28 while AT29C256-12JI uses PLCC-32. They are not pin-compatible due to different pin counts (28 vs. 32) and physical layouts. Substitution requires PCB redesign. Both parts implement the same AT29C256-12TI core functionality, including 120 ns access, page programming, and data protection - but mechanical integration is mutually exclusive. Always verify package footprint before selecting either variant.
AT29C256-12TI 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:
- 120 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
AT29C256-12TI FAQ
1.How can I place an order for AT29C256-12TI through Aetrix?
Please submit a Request for Quotation (RFQ) for AT29C256-12TI 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 reliable?
The price and inventory of AT29C256-12TI 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 is usually 5 days.
3.What payment methods are accepted for AT29C256-12TI?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for AT29C256-12TI transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for AT29C256-12TI?
AT29C256-12TI orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your AT29C256-12TI 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?
For technical support, including AT29C256-12TI datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your AT29C256-12TI requirements.
6.How does Aetrix verify that AT29C256-12TI is sourced from the original manufacturer or authorized distributors?
All AT29C256-12TI 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 meets industry standards.
7.What is the process for return or replacement of AT29C256-12TI?
All AT29C256-12TI units undergo pre-shipment inspection (PSI). If there is an issue with AT29C256-12TI, 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 part is unused and in its original packaging.
Return procedure for AT29C256-12TI:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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