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Microchip Technology AT29C256-12JI-T
- Part No.:
- AT29C256-12JI-T
- Manufacturer:
- Microchip Technology
- Category:
- Memory
- Package:
- 32-LCC (J-Lead)
- Datasheet:
-
AT29C256-12JI-T.pdf
- Description:
- IC FLASH 256KBIT PARALLEL 32PLCC
- Quantity:
- Payment:
- Shipping:
Inventory:3,737
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Product details
Overview
AT29C256-12JI-T from Atmel is a 256 Kbit (32K × 8) 5V-only Flash memory IC used for nonvolatile program/data storage in embedded systems, supporting in-system reprogramming without high-voltage programming supplies. It delivers 120 ns read access time, 10 ms page (64-byte) program time, and operates across -40°C to +85°C industrial temperature range in a 32-lead PLCC package.
For engineers reviewing the AT29C256-12JI-T datasheet, AT29C256-12JI-T pinout, AT29C256-12JI-T application, or AT29C256-12JI-T equivalent, key selection considerations include its 5V-only operation, hardware/software data protection, DATA polling and toggle-bit end-of-write detection, and compatibility with standard microcontroller address/data buses.
Technical Context
The AT29C256-12JI-T implements a page-programmable Flash architecture where 64-byte pages are loaded via byte-load cycles using WE or CE control, then internally erased and programmed under autonomous timing control. Its dual-line chip enable (CE) and output enable (OE) logic enables flexible bus interfacing without contention.
Hardware data protection includes VCC sense (<3.8 V inhibits programming), 5 ms power-on delay, and noise filtering on WE/CE inputs; software protection uses a three-byte command sequence (AAh/55h/A0h) to enable/disable write operations. The device supports product identification mode (manufacturer code 1Fh, device code DCh) and optional six-byte software chip erase.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Memory Density | 256 Kbit (32,768 × 8), sufficient for firmware boot code or configuration tables in resource-constrained controllers |
| Read Access Time | 120 ns max - determines minimum instruction fetch latency when mapped into microcontroller memory space |
| Page Program Time | 10 ms typical - defines minimum interval between successive 64-byte writes during firmware updates |
| Endurance | >10,000 write/erase cycles per sector - supports field-upgradable applications requiring moderate reprogramming frequency |
| VCC Supply | 5 V ± 10% - eliminates need for dedicated programming voltage regulators in 5V system designs |
| Standby Current | 300 µA CMOS - enables low-power retention in battery-backed or energy-sensitive systems |
| Operating Temperature | -40°C to +85°C - qualified for industrial environments including motor controls and instrumentation |
Pinout & Package
AT29C256-12JI-T is housed in a 32-lead Plastic J-Leaded Chip Carrier (PLCC) package per JEDEC MS-016, Variation AE. Pins 1 and 17 are No Connect (NC). Pin functions are electrically defined and validated per Atmel's official datasheet Rev. 0046O–FLASH–06/02.
| 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 compatible with TTL/CMOS logic levels; carries data during read, byte load, and program verification |
| CE | Chip Enable | Active-low chip select; must be low for read, program, or erase; high-Z outputs when high |
| OE | Output Enable | Active-low output control; enables data output only when CE is also low; prevents bus contention |
| WE | Write Enable | Active-low control for byte loading and program initiation; used with CE to latch addresses and data |
| VCC | Power Supply | +5 V ± 10% main supply; powers all internal logic and charge pumps for Flash programming |
| GND | Ground | Reference return path for all signals and power; requires low-impedance connection to minimize noise during programming |
Key Features
| Feature | Design Value |
|---|---|
| 5V-only reprogramming | Eliminates external high-voltage generators, simplifying PCB layout and reducing BOM count in 5V systems |
| Internal program timer & control | Automates erase-and-program sequence after byte loading, freeing MCU resources during 10 ms write cycle |
| DATA polling (I/O7) and toggle-bit (I/O6) | Enables real-time, non-intrusive detection of program/erase completion without fixed delays or status registers |
| Hardware + software data protection | Prevents accidental writes during power transitions or noise events, and allows user-controlled lock/unlock of memory regions |
| CMOS/TTL I/O compatibility | Direct interface with legacy 8-bit microcontrollers (e.g., 8051, Z80) and FPGA I/O banks without level-shifting |
Applications
| Industrial PLC Firmware Storage | Medical Device Configuration Memory |
|---|---|
Use Scenario: Storing firmware update images and calibration 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 as memory-mapped peripheral with 120 ns read latency. Use Value: Industrial temperature rating (-40°C to +85°C) and >10,000 endurance cycles ensure reliable operation over extended service life with periodic field updates. |
Use Scenario: Holding patient-specific settings and safety-critical calibration data in portable diagnostic equipment requiring data retention during battery replacement. IC Role / Device Role / Timing Role: Secure, low-power configuration store; leverages hardware/software write protection to prevent corruption during brown-out conditions. Use Value: 300 µA standby current extends battery life, while DATA polling enables deterministic firmware update timing without CPU overhead. |
| Legacy Embedded System Boot ROM | Communications Equipment Parameter Table |
Use Scenario: Replacing EPROMs in aging telecom infrastructure boards where socketed 28-pin DIP packages are no longer available. IC Role / Device Role / Timing Role: Drop-in replacement for 27C256 EPROMs in 8-bit address/data bus systems; identical pinout in PDIP variant (AT29C256-12PI). Use Value: 5V-only operation avoids redesigning power delivery; 120 ns access matches original EPROM timing, preserving system timing margins. |
Use Scenario: Storing channel mapping, gain tables, and protocol stack parameters in base station transceivers requiring infrequent but verified updates. IC Role / Device Role / Timing Role: Page-programmable parameter store accessed via microcontroller SPI-to-parallel bridge or direct bus interface. Use Value: 64-byte page granularity aligns with typical parameter block sizes; toggle-bit detection ensures robust write verification in electrically noisy RF environments. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar Flash memory applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| AT29C256-12PI | Same die, 28-lead PDIP package (28P6); no NC pins; wider body (0.600") | Preferred for through-hole prototyping or legacy board rework where PLCC socketing is unavailable | Select when mechanical fit or hand-soldering requirements favor DIP over surface-mount PLCC |
| SST39SF256-120-4C-NHE | 5V Flash with 120 ns access, 28-pin TSOP; supports both byte and word programming; no hardware VCC sense protection | Higher pin density and lower profile; lacks Atmel's dual hardware/software write protection scheme | Choose for space-constrained designs needing TSOP footprint, accepting trade-off in protection robustness |
Compared with AT29C256-12JI-T, the AT29C256-12PI offers identical electrical behavior in a through-hole package ideal for lab validation, while SST39SF256 provides TSOP packaging and word-program capability at the cost of reduced hardware-level write safeguards.
Availability
AT29C256-12JI-T is available at Aetrix Electronics and suitable for industrial control systems, medical diagnostics equipment, legacy embedded upgrades, and communications infrastructure requiring stable component supply with long-term lifecycle support.
Supply support for AT29C256-12JI-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 semiconductor manufacturer specializing in microcontrollers, Flash memory, and secure authentication devices.
The AT29C256 product line was designed for cost-sensitive, 5V-based embedded systems requiring field-upgradable nonvolatile storage with simple programming interfaces and robust data integrity features.
FAQ
What is the maximum operating temperature range for the AT29C256-12JI-T?
The AT29C256-12JI-T is rated for industrial temperature operation from -40°C to +85°C. This specification is guaranteed per the ordering information table in the official Atmel datasheet Rev. 0046O–FLASH–06/02 and applies specifically to the -JI suffix variant. The 'I' designation confirms industrial-grade qualification, making AT29C256-12JI-T suitable for deployment in harsh environments such as factory floors or outdoor telecommunications enclosures.
Does the AT29C256-12JI-T require external high-voltage programming supplies?
No, the AT29C256-12JI-T operates with 5V-only reprogramming - no external VPP or high-voltage generator is needed. Programming is initiated using standard 5V logic levels applied to WE and CE, with internal charge pumps generating necessary voltages. This design eliminates external HV circuitry, reducing system complexity and cost. All programming commands for AT29C256-12JI-T are executed using the same 5V supply that powers normal read operations.
How does the AT29C256-12JI-T indicate completion of a page program cycle?
The AT29C256-12JI-T supports two hardware-based end-of-program detection methods: DATA polling on I/O7 (complement of loaded data until completion, then true data) and toggle-bit behavior on I/O6 (toggling between 0 and 1 until completion, then stabilization). Both mechanisms are active during the 10 ms internal program cycle and require no additional status registers or clocks. Engineers can monitor either signal on AT29C256-12JI-T to synchronize subsequent memory accesses without fixed timing delays.
Can the AT29C256-12JI-T be used as a direct replacement for older 27C256 EPROMs?
Yes, the AT29C256-12JI-T is functionally and electrically compatible with 27C256 EPROMs in read mode, sharing identical 32K × 8 organization, pinout (in PLCC), and 5V operation. However, AT29C256-12JI-T adds in-system reprogrammability, hardware/software write protection, and faster erase/program cycles. For drop-in replacement, verify that the host system's OE/CE/WE timing meets AT29C256-12JI-T's AC specifications - particularly tOE (max 50 ns) and tCE (max 120 ns).
What package type is used for the AT29C256-12JI-T?
The AT29C256-12JI-T uses a 32-lead Plastic J-Leaded Chip Carrier (PLCC) package, designated as 32J per Atmel's ordering information. This surface-mount package features gull-wing leads, a ceramic-like body, and a pin 1 identifier notch. Pins 1 and 17 are designated No Connect (NC) and must remain unconnected in PCB layout. The PLCC form factor provides robust thermal and mechanical performance for industrial applications where the AT29C256-12JI-T is commonly deployed.
AT29C256-12JI-T Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Microchip Technology
- Series:
- -
- Package/Case:
- 32-LCC (J-Lead)
- 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-PLCC (13.97x11.43)
AT29C256-12JI-T FAQ
1.How can I place an order for AT29C256-12JI-T through Aetrix?
Please submit a Request for Quotation (RFQ) for AT29C256-12JI-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 AT29C256-12JI-T reliable?
The price and inventory of AT29C256-12JI-T are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for AT29C256-12JI-T is usually 5 days.
3.What payment methods are accepted for AT29C256-12JI-T?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for AT29C256-12JI-T transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for AT29C256-12JI-T?
AT29C256-12JI-T orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your AT29C256-12JI-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 AT29C256-12JI-T?
For technical support, including AT29C256-12JI-T datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your AT29C256-12JI-T requirements.
6.How does Aetrix verify that AT29C256-12JI-T is sourced from the original manufacturer or authorized distributors?
All AT29C256-12JI-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 AT29C256-12JI-T meets industry standards.
7.What is the process for return or replacement of AT29C256-12JI-T?
All AT29C256-12JI-T units undergo pre-shipment inspection (PSI). If there is an issue with AT29C256-12JI-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 AT29C256-12JI-T part is unused and in its original packaging.
Return procedure for AT29C256-12JI-T:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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