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Microchip Technology AT29C256-70JI
- Part No.:
- AT29C256-70JI
- Manufacturer:
- Microchip Technology
- Category:
- Memory
- Package:
- 32-LCC (J-Lead)
- Datasheet:
-
AT29C256-70JI.pdf
- Description:
- IC FLASH 256KBIT PARALLEL 32PLCC
- Quantity:
- Payment:
- Shipping:
Inventory:2,748
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Product details
Overview
AT29C256-70JI from Atmel is a 256 Kbit (32K × 8) 5V-only Flash memory IC designed for in-system reprogrammability in embedded controllers and firmware storage applications. It delivers 70 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 AT29C256-70JI datasheet, AT29C256-70JI pinout, AT29C256-70JI application, or AT29C256-70JI equivalent, key selection criteria include its 5V-only operation, hardware/software data protection, DATA polling and toggle-bit program status detection, and PLCC-32 packaging for legacy board compatibility.
Technical Context
The AT29C256-70JI implements a nonvolatile Flash architecture with internal address/data latches enabling full 64-byte page loading before simultaneous programming. Its dual-line chip enable (CE) and output enable (OE) control allows flexible bus contention management during read cycles.
Programming uses a software-controlled command sequence (e.g., AAh/55h/A0h) to initiate page writes or chip erase, with hardware safeguards including VCC sense (<3.8 V inhibition), 5 ms power-on delay, and noise filtering on WE/CE inputs to prevent spurious writes.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Memory Size | 256 Kbit (32,768 × 8 bits) - sufficient for boot code, configuration tables, or firmware patches in microcontroller-based systems |
| Read Access Time | 70 ns - enables direct execution from flash in timing-critical 8-bit/16-bit MCU interfaces without wait states |
| Page Program Time | 10 ms per 64-byte page - reduces firmware update latency compared to byte-by-byte programming |
| VCC Supply | 5 V ± 10% - eliminates need for dedicated programming voltage rails in system design |
| Endurance | >10,000 write/erase cycles - supports field-upgradable firmware with long-term reliability |
| Standby Current | 300 µA (CMOS) - minimizes power in sleep-mode embedded applications |
| Operating Temp | -40°C to +85°C - certified for industrial environments including motor controls and instrumentation |
Pinout & Package
AT29C256-70JI is packaged in a 32-lead Plastic J-Leaded Chip Carrier (PLCC-32), compliant with JEDEC MS-016 Variation AE. Pin 1 is marked by a corner notch; pins 1 and 17 are no-connect (NC) and must remain unconnected in PCB layout.
| 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 parallel interface; I/O7 provides DATA polling feedback, I/O6 toggles during program/erase |
| CE | Chip Enable | Active-low device select; must be low with OE low and WE high for valid read access |
| OE | Output Enable | Active-low output control; high-Z state when asserted high to prevent bus contention |
| WE | Write Enable | Active-low control for byte loads and programming initiation; synchronized with CE for latch timing |
| VCC | Power Supply | +5 V supply; internally regulated for programming; VCC sense disables writes below 3.8 V |
| GND | Ground | Reference return path for all signals and power; requires low-impedance PCB plane |
Key Features
| Feature | Design Value |
|---|---|
| 5V-only reprogramming | Eliminates need for external 12 V programming supplies, simplifying power architecture and reducing BOM cost |
| Hardware data protection | VCC sense, 5 ms power-on delay, and 15 ns noise filtering prevent accidental writes during brown-out or EMI events |
| Software data protection | User-configurable lock via three-command sequence (AAh/55h/A0h); persists through power cycles until explicitly disabled |
| DATA polling & toggle bit | Real-time program status monitoring via I/O7 complement or I/O6 toggling-no external timers or interrupts required |
| Page programming | 64-byte internal latches free address/data bus during 10 ms internal erase-program cycle, enabling background operations |
Applications
| Industrial PLC Firmware Storage | Embedded Controller Boot Memory |
|---|---|
Use Scenario: Storing ladder logic programs and I/O configuration data in programmable logic controllers requiring field updates without hardware changes. IC Role / Device Role / Timing Role: Nonvolatile firmware storage with in-system reprogrammability; 70 ns access supports real-time scan cycle execution. Use Value: Enables remote firmware upgrades via serial interface while maintaining deterministic scan timing due to fast read performance. | Use Scenario: Holding boot code and initialization routines for 8-bit microcontrollers in HVAC control panels operating across wide ambient temperatures. IC Role / Device Role / Timing Role: Primary boot ROM accessed at power-on reset; industrial temp rating ensures reliability in uncontrolled enclosures. Use Value: 300 µA standby current extends battery backup life during mains failure; 5V-only operation avoids level-shifting complexity. |
| Medical Device Configuration Storage | Automotive Body Control Module EEPROM Replacement |
Use Scenario: Retaining calibration coefficients and user preferences in portable diagnostic equipment subject to regulatory traceability requirements. IC Role / Device Role / Timing Role: Secure parameter storage with software/hardware write protection preventing unintended modification during operation. Use Value: >10,000 endurance cycles support lifetime recalibration; DATA polling ensures verified write completion for audit logs. | Use Scenario: Replacing older EEPROMs in body control modules where faster programming and higher density are needed for feature expansion. IC Role / Device Role / Timing Role: Firmware and configuration storage with page-level updates synchronized to CAN bus firmware download commands. Use Value: 10 ms page programming reduces total update time vs. byte-wise EEPROM; PLCC-32 footprint maintains legacy PCB compatibility. |
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 tolerance; 70 ns access; 128K × 16 organization | Requires level translation for pure 5 V systems; wider data bus suits DSP interfaces | Select when migrating to lower-voltage domains or needing 16-bit data path |
| SST39VF256A-70-4C-NHE | 3.3 V only; 70 ns access; 32K × 8 organization; supports 12 V programming mode | Not 5 V compatible; lacks hardware VCC sense protection; different command set | Choose only if system already uses 3.3 V supply and requires SST's enhanced block-erase flexibility |
Compared with AM29LV256M-70EC and SST39VF256A-70-4C-NHE, the AT29C256-70JI uniquely provides true 5V-only operation with integrated hardware write protection and PLCC-32 packaging-critical for drop-in replacement in legacy industrial designs without voltage rail changes.
Availability
AT29C256-70JI is available at Aetrix Electronics and suitable for industrial PLC firmware storage, embedded controller boot memory, and medical device configuration storage requiring stable component supply and long-term obsolescence management.
Supply support for AT29C256-70JI 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, nonvolatile memory, and secure authentication devices.
The AT29C256 product line was engineered 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 AT29C256-70JI?
The AT29C256-70JI 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). The "I" suffix in AT29C256-70JI explicitly denotes industrial grade, distinguishing it from commercial-grade variants like AT29C256-70JC.
Does the AT29C256-70JI require external high-voltage programming signals?
No, the AT29C256-70JI does not require external high-voltage programming signals. It is a 5-volt-only Flash memory: all programming and erasure operations-including page programming and chip erase-are executed using standard 5 V logic levels and specific software command sequences (e.g., AAh/55h/A0h). Hardware protection features such as VCC sense ensure programming is inhibited below 3.8 V.
How is program completion detected on the AT29C256-70JI?
Program completion on the AT29C256-70JI can be detected using two hardware-supported methods: DATA polling on I/O7 (which returns the complement of loaded data until completion) or monitoring the toggle bit on I/O6 (which alternates between 0 and 1 during programming and stabilizes upon completion). Both methods are specified in the Device Operation section and require no external circuitry or timers.
What package type is used for the AT29C256-70JI?
The AT29C256-70JI uses a 32-lead Plastic J-Leaded Chip Carrier (PLCC-32) package, designated as "32J" in Atmel's Ordering Information. Pin 1 is identified by a corner notch; pins 1 and 17 are no-connect (NC) and must remain unconnected. Mechanical dimensions conform to JEDEC MS-016, Variation AE.
Can the AT29C256-70JI be used as a direct replacement for standard EPROMs like the 27C256?
The AT29C256-70JI is pin-compatible with the 27C256 EPROM in PLCC-32 packaging and shares identical address/data bus connections (A0–A14, I/O0–I/O7, CE, OE, WE), but differs critically in write methodology: it requires software command sequences for programming rather than UV erasure and high-voltage programming pulses. System firmware must implement the AT29C256-70JI's page-program protocol and status polling-not just replicate 27C256 timing.
AT29C256-70JI Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Microchip Technology
- Series:
- -
- Package/Case:
- 32-LCC (J-Lead)
- Packaging:
- Tube
- 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:
- -40°C ~ 85°C (TC)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 32-PLCC (13.97x11.43)
AT29C256-70JI FAQ
1.How can I place an order for AT29C256-70JI through Aetrix?
Please submit a Request for Quotation (RFQ) for AT29C256-70JI 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 AT29C256-70JI reliable?
The price and inventory of AT29C256-70JI are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for AT29C256-70JI is usually 5 days.
3.What payment methods are accepted for AT29C256-70JI?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for AT29C256-70JI transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for AT29C256-70JI?
AT29C256-70JI orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your AT29C256-70JI 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 AT29C256-70JI?
For technical support, including AT29C256-70JI datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your AT29C256-70JI requirements.
6.How does Aetrix verify that AT29C256-70JI is sourced from the original manufacturer or authorized distributors?
All AT29C256-70JI 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 AT29C256-70JI meets industry standards.
7.What is the process for return or replacement of AT29C256-70JI?
All AT29C256-70JI units undergo pre-shipment inspection (PSI). If there is an issue with AT29C256-70JI, 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 AT29C256-70JI part is unused and in its original packaging.
Return procedure for AT29C256-70JI:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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