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Microchip Technology AT29C256-70JC-T
- Part No.:
- AT29C256-70JC-T
- Manufacturer:
- Microchip Technology
- Category:
- Memory
- Package:
- 32-LCC (J-Lead)
- Datasheet:
-
AT29C256-70JC-T.pdf
- Description:
- IC FLASH 256KBIT PARALLEL 32PLCC
- Quantity:
- Payment:
- Shipping:
Inventory:2,955
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Product details
Overview
AT29C256-70JC-T from Atmel is a 256 Kbit (32K × 8) 5V-only Flash memory IC used for nonvolatile program/data storage in embedded systems. It delivers 70 ns read access time, supports page programming of 64-byte blocks in 10 ms, and operates across industrial temperature range (–40°C to +85°C) in a 32-lead PLCC package.
For engineers reviewing the AT29C256-70JC-T datasheet, AT29C256-70JC-T pinout, AT29C256-70JC-T application, or AT29C256-70JC-T 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 legacy SRAM-based memory interfaces.
Technical Context
The AT29C256-70JC-T implements a page-programmable Flash PEROM architecture with internal address and data latches for 64-byte writes. Its control logic uses CE/OE/WE three-line protocol identical to static RAM, enabling drop-in replacement in existing designs without bus interface redesign.
Programming relies on software command sequences (e.g., 5555h/2AAAh/A0h) for page write and chip erase, while hardware protection includes VCC sense (<3.8 V inhibit), 5 ms power-on delay, and noise filtering on WE/CE inputs. End-of-program detection is supported via I/O7 DATA polling and I/O6 toggle-bit behavior.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Memory Size | 256 Kbit (32,768 × 8), sufficient for firmware boot code or configuration tables in microcontroller-based systems |
| Read Access Time | 70 ns - enables direct interfacing with 10–14 MHz microcontrollers without wait states |
| Page Program Time | 10 ms per 64-byte page - allows efficient field updates without full-chip erasure |
| VCC Supply | 5 V ± 10% - eliminates need for dedicated programming voltage generators |
| Endurance | >10,000 write/erase cycles - supports long-term field firmware upgrades in industrial controllers |
| Standby Current | 300 µA CMOS - suitable for low-power battery-backed applications |
| Operating Temp | –40°C to +85°C - qualified for industrial automation and automotive under-hood modules |
Pinout & Package
AT29C256-70JC-T is housed in a 32-lead Plastic J-Leaded Chip Carrier (PLCC) package, JEDEC MS-016 compliant, with pins 1 and 17 designated as No Connect (NC). The package features gull-wing leads, 1.27 mm pitch, and 13.4 mm × 13.4 mm body size.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| A0–A14 | Address Inputs | 15-bit address bus supporting full 32K-word addressing; A6–A14 define page address during programming |
| I/O0–I/O7 | Bidirectional Data Bus | 8-bit data path; I/O7 used for DATA polling, I/O6 for toggle-bit status monitoring |
| CE | Chip Enable | Active-low chip select; must be low for read/write; high-Z output when high |
| OE | Output Enable | Active-low output control; used with CE to prevent bus contention during reads |
| WE | Write Enable | Active-low write strobe; controls byte load timing and initiates programming sequence |
| VCC | Power Supply | +5 V supply; powers core logic and I/O buffers; internally monitored for programming safety |
| GND | Ground | Reference for all signals and power; pin 16 in PLCC layout |
| NC / DC | No Connect / Don't Connect | Pins 1 and 17 - must remain unconnected per datasheet; no internal connection or function |
Key Features
| Feature | Design Value |
|---|---|
| 5V-only reprogramming | Eliminates need for external 12 V programming supplies, simplifying system power architecture |
| Hardware data protection | VCC sense, 5 ms power-on delay, and noise filtering prevent accidental writes during brown-out or EMI events |
| Software data protection | User-configurable enable/disable via 3-byte unlock sequence; prevents unauthorized firmware modification |
| DATA polling & toggle bit | Real-time, bus-compatible programming status feedback without requiring external timers or interrupts |
| CMOS/TTL I/O compatibility | Direct interface with both 5 V CMOS and TTL logic families without level-shifting circuitry |
Applications
| Industrial PLC Firmware Storage | Medical Device Configuration Memory |
|---|---|
Use Scenario: Storing ladder logic programs and I/O mapping tables in programmable logic controllers subject to frequent field updates. IC Role / Device Role / Timing Role: Nonvolatile firmware storage with in-system reprogrammability and industrial temperature tolerance. Use Value: Enables remote firmware patches via serial interface without removing the module; 10,000-cycle endurance ensures >10-year service life at quarterly update intervals. | Use Scenario: Retaining calibration coefficients, patient history logs, and safety-critical device settings in portable diagnostic equipment. IC Role / Device Role / Timing Role: Secure, low-power configuration memory with hardware/software write protection. Use Value: Prevents corruption during power loss or ESD events; 300 µA standby current extends battery life in handheld units between charges. |
| Automotive Body Control Module | Legacy Industrial HMI Display |
Use Scenario: Holding lighting profiles, door lock logic, and sensor thresholds in vehicle body control units operating under wide thermal stress. IC Role / Device Role / Timing Role: Automotive-grade Flash memory with –40°C to +85°C operation and robust noise immunity. Use Value: Meets AEC-Q100 stress requirements via design (not qualification); VCC-sense protection avoids spurious writes during engine cranking voltage dips. | Use Scenario: Replacing obsolete EPROMs in aging human-machine interface panels where PCB layout cannot be modified. IC Role / Device Role / Timing Role: Pin- and timing-compatible SRAM-style Flash memory with identical CE/OE/WE control. Use Value: Direct socket replacement for 27C256 EPROMs; 70 ns access time maintains real-time display refresh timing without system redesign. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar Flash memory applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| AM29LV256M-70EC | 3.3 V core with 5 V I/O tolerant; 70 ns read; 100 ms typical sector erase vs. 10 ms chip erase | Requires dual-supply design; not 5V-only; lacks software chip erase command | Choose if migrating to lower-voltage systems with mixed 3.3/5 V signaling |
| SST39VF256A-70-4C-NHE | 3.3 V only; 70 ns read; 10 ms byte/page program; no hardware VCC-sense protection | Not compatible with 5 V-only systems; requires external reset supervision for safe programming | Choose for cost-sensitive 3.3 V designs where external voltage monitoring is already present |
Compared with AM29LV256M-70EC and SST39VF256A-70-4C-NHE, the AT29C256-70JC-T uniquely provides true 5V-only operation with integrated VCC-sense, software chip erase, and industrial-temp PLCC packaging - making it the only option for legacy 5 V controller upgrades requiring zero hardware changes.
Availability
AT29C256-70JC-T is available at Aetrix Electronics and suitable for industrial PLC firmware storage, medical device configuration memory, and automotive body control module applications requiring stable component supply and long-lifecycle support.
Supply support for AT29C256-70JC-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 in-system programmable nonvolatile storage in 5 V embedded systems, targeting replacements for EPROM and EEPROM in industrial, medical, and automotive applications.
FAQ
What is the maximum operating frequency supported by AT29C256-70JC-T?
The AT29C256-70JC-T does not operate at a clock frequency - it is an asynchronous parallel Flash memory. Its AC timing is defined by access times: tACC = 70 ns, meaning it supports bus cycles up to approximately 14 MHz (1/70 ns) when interfaced with microcontrollers or ASICs using standard SRAM timing. The device has no internal clock input.
Does AT29C256-70JC-T require external high-voltage circuitry for programming?
No, AT29C256-70JC-T does not require external high-voltage circuitry. It is a 5V-only Flash memory: all programming and erasure operations use standard 5 V supply levels. Internal charge pumps generate necessary voltages, and software command sequences (e.g., 5555h/2AAAh) initiate page writes or chip erase - eliminating need for 12 V programmers or external HV generators.
How is programming status detected on AT29C256-70JC-T?
AT29C256-70JC-T provides two hardware-supported methods: DATA polling monitors I/O7 (complement of last written data until completion), and the toggle bit monitors I/O6 (toggles between 0/1 during programming and stops when complete). Both methods allow polling over the same data bus used for writes - no additional pins or external logic required.
Can AT29C256-70JC-T replace a 27C256 EPROM in an existing design?
Yes, AT29C256-70JC-T is a functional and pin-compatible replacement for 27C256 EPROMs in 5 V systems. It matches the 28-pin DIP footprint (when using -70PC variant) or 32-pin PLCC (-70JC-T), uses identical CE/OE/WE control, and offers faster 70 ns access vs. typical 250 ns EPROMs - often enabling removal of wait-state logic.
What is the purpose of pins 1 and 17 on the AT29C256-70JC-T PLCC package?
Pins 1 and 17 on the AT29C256-70JC-T PLCC package are designated as No Connect (NC) / Don't Connect (DC) per the official Atmel datasheet. They have no internal connection and must remain unconnected in PCB layout. Routing or soldering to these pins may cause functional or reliability issues due to potential parasitic coupling or mechanical stress.
AT29C256-70JC-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:
- 70 ns
- Voltage - Supply:
- 4.5V ~ 5.5V
- Operating Temperature:
- 0°C ~ 70°C (TC)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 32-PLCC (13.97x11.43)
AT29C256-70JC-T FAQ
1.How can I place an order for AT29C256-70JC-T through Aetrix?
Please submit a Request for Quotation (RFQ) for AT29C256-70JC-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 AT29C256-70JC-T reliable?
The price and inventory of AT29C256-70JC-T are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for AT29C256-70JC-T is usually 5 days.
3.What payment methods are accepted for AT29C256-70JC-T?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for AT29C256-70JC-T transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for AT29C256-70JC-T?
AT29C256-70JC-T orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your AT29C256-70JC-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 AT29C256-70JC-T?
For technical support, including AT29C256-70JC-T datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your AT29C256-70JC-T requirements.
6.How does Aetrix verify that AT29C256-70JC-T is sourced from the original manufacturer or authorized distributors?
All AT29C256-70JC-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 AT29C256-70JC-T meets industry standards.
7.What is the process for return or replacement of AT29C256-70JC-T?
All AT29C256-70JC-T units undergo pre-shipment inspection (PSI). If there is an issue with AT29C256-70JC-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 AT29C256-70JC-T part is unused and in its original packaging.
Return procedure for AT29C256-70JC-T:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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