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Microchip Technology AT29C256-70JI-T
- Part No.:
- AT29C256-70JI-T
- Manufacturer:
- Microchip Technology
- Category:
- Memory
- Package:
- 32-LCC (J-Lead)
- Datasheet:
-
AT29C256-70JI-T.pdf
- Description:
- IC FLASH 256KBIT PARALLEL 32PLCC
- Quantity:
- Payment:
- Shipping:
Inventory:1,476
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Product details
Overview
AT29C256-70JI-T from Atmel is a 256 Kbit (32 K × 8) 5V-only Flash memory IC designed for in-system reprogrammability in embedded control and firmware storage applications. It delivers 70 ns read access time, supports page programming of 64 bytes per cycle, features hardware and software data protection, and operates across the industrial temperature range (–40°C to +85°C) in a 32-lead PLCC package.
For engineers reviewing the AT29C256-70JI-T datasheet, AT29C256-70JI-T pinout, AT29C256-70JI-T application, or AT29C256-70JI-T equivalent, key selection criteria include its 5V-only operation, 10 ms page program time, CMOS/TTL-compatible I/O, DATA polling and toggle-bit end-of-write detection, and industrial-grade reliability with >10,000 write/erase cycles.
Technical Context
The AT29C256-70JI-T implements a nonvolatile Flash architecture with internal address/data latches for 64-byte page loading, automatic erase-and-program sequencing controlled by an on-chip timer, and dual-line chip enable (CE) and output enable (OE) for bus contention management. Its read interface mirrors static RAM timing behavior, enabling drop-in replacement in legacy SRAM-based designs without logic changes.
Programming requires no external high-voltage supply: all operations-including page program, chip erase, and software data protection enable/disable-are executed via 5V-only command sequences applied to standard address/data/control pins. End-of-program status is confirmed via DATA polling on I/O7 or toggle-bit monitoring on I/O6, both usable at any point during the internal 10 ms programming window.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Memory Capacity | 256 Kbit (32,768 × 8), sufficient for boot code, configuration tables, or firmware patches in microcontroller systems. |
| Read Access Time | 70 ns maximum-enables direct interfacing with 14 MHz+ microcontrollers without wait states. |
| Page Program Time | 10 ms typical-supports rapid field updates of 64-byte firmware segments without full-chip erasure. |
| VCC Supply | 5 V ± 10%-eliminates need for dedicated programming voltage regulators in system design. |
| Endurance | >10,000 write/erase cycles per sector-validates long-term use in devices requiring frequent parameter logging or calibration updates. |
| Standby Current | 300 µA typical (CMOS mode)-meets low-power requirements for battery-backed or energy-conscious embedded systems. |
| Operating Temperature | –40°C to +85°C-qualified for industrial automation, motor control, and outdoor instrumentation environments. |
Pinout & Package
AT29C256-70JI-T is housed in a 32-lead Plastic J-Leaded Chip Carrier (PLCC) package, compliant with JEDEC MS-016 Variation AE. Pin 1 is marked by a corner notch; pins 1 and 17 are No Connect (NC). The package is lead-free and RoHS-compliant per Atmel documentation.
| 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 used for DATA polling, I/O6 for toggle-bit status indication during program/erase. |
| CE | Chip Enable | Active-low global device select; must be low for read, program, or erase; high state forces outputs to high-Z. |
| OE | Output Enable | Active-low output gate; controls data assertion on I/O lines during read; high disables outputs regardless of CE/WE state. |
| WE | Write Enable | Active-low control for byte load and program initiation; timing-critical for 150 µs inter-byte loading window in page mode. |
| VCC | Power Supply | +5 V ± 10% main supply; powers core logic and I/O buffers; internal VCC sense prevents programming below 3.8 V. |
| GND | Ground | Reference for all input thresholds and output levels; decoupling capacitor placement near pin 32 is critical for noise immunity. |
| NC | No Connect | Pins 1 and 17 are unconnected internally; must remain floating-no pull-up/down or routing required. |
Key Features
| Feature | Design Value |
|---|---|
| 5V-only in-system programming | Eliminates need for external 12 V programming supplies, simplifying PCB layout and reducing BOM count in field-upgradable systems. |
| Hardware data protection | VCC sense, power-on delay, and noise filtering prevent accidental writes during power ramp-up or EMI events-no firmware intervention required. |
| Software data protection | Three-byte unlock sequence (5555h/2AAAh/80h then 5555h/2AAAh/20h) enables/disables write capability, securing firmware against unintended overwrites. |
| DATA polling & toggle-bit detection | Allows real-time, non-blocking verification of program completion using only standard read cycles-no dedicated status register or interrupt needed. |
| Page-based 64-byte programming | Reduces update latency vs. full-chip erase; enables efficient patching of small firmware sections while preserving unrelated memory contents. |
Applications
| Industrial PLC Firmware Storage | Automotive ECU Bootloader Memory |
|---|---|
|
Use Scenario: Storing and updating ladder logic programs and I/O mapping tables in programmable logic controllers deployed in factory-floor environments. IC Role / Device Role / Timing Role: Nonvolatile firmware storage with in-system reprogrammability; provides 70 ns read access for deterministic scan-cycle execution. Use Value: Enables remote firmware upgrades without controller removal; industrial temperature rating ensures stable operation amid ambient thermal cycling. |
Use Scenario: Holding bootloader code and calibration data in engine control units subject to automotive qualification requirements. IC Role / Device Role / Timing Role: Secure, field-upgradable memory for safety-critical initialization routines; software data protection prevents corruption during ignition transients. Use Value: >10,000 endurance cycles support repeated calibration updates over vehicle lifetime; 5V-only operation integrates cleanly with automotive 5V power domains. |
| Medical Device Configuration Memory | Networking Equipment Boot Image Storage |
|
Use Scenario: Retaining user-configurable parameters (e.g., alarm thresholds, display preferences) in portable diagnostic instruments with battery backup. IC Role / Device Role / Timing Role: Low-power nonvolatile storage; 300 µA standby current extends battery life during idle periods between measurements. Use Value: Hardware write inhibition prevents data loss during brown-out conditions; DATA polling allows precise timing of configuration saves. |
Use Scenario: Storing boot images and FPGA configuration bitstreams in Ethernet switches and routers requiring fast, reliable startup. IC Role / Device Role / Timing Role: Primary boot memory interfaced directly to microprocessor address/data bus; 70 ns access minimizes boot latency. Use Value: Page programming enables rapid field updates of security patches without disrupting network uptime; CMOS/TTL compatibility ensures interoperability with legacy SoCs. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar Flash memory applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| MX29LV256 (Macronix) | 3.3 V core supply with 5 V tolerant I/O; 70 ns access; 100,000 endurance cycles. | Requires level-shifting for pure 5 V systems; better suited for mixed-voltage designs with lower power budgets. | Select MX29LV256 when migrating to 3.3 V platforms or extending endurance beyond 10K cycles. |
| SST39VF256 (Microchip) | 3.3 V operation only; 70 ns access; 100K endurance; supports byte-write without page constraints. | Incompatible with 5 V-only buses; lacks hardware VCC-sense protection; requires different unlock sequences. | Choose SST39VF256 only in new 3.3 V designs where byte-level writes and higher endurance outweigh 5 V compatibility loss. |
Compared with AT29C256-70JI-T, MX29LV256 offers higher endurance and lower voltage flexibility but demands I/O voltage translation, while SST39VF256 enables true byte writes yet mandates full system voltage redesign-neither is pin-compatible, and both require PCB layout and firmware adaptation.
Availability
AT29C256-70JI-T is available at Aetrix Electronics and suitable for industrial automation, automotive electronics, and medical instrumentation requiring stable component supply and long-term obsolescence management.
Supply support for AT29C256-70JI-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, Flash memory, and secure authentication ICs for embedded systems.
The AT29C256 product line was engineered for cost-sensitive, 5V-based embedded systems needing field-upgradable firmware storage with industrial temperature resilience and robust data integrity features.
FAQ
What is the operating temperature range for the AT29C256-70JI-T?
The AT29C256-70JI-T is rated for industrial operation from –40°C to +85°C. This specification is guaranteed per the ordering code suffix "I" and validated across electrical parameters including read access time, program timing, and standby current. The PLCC package's thermal characteristics support sustained operation within this range under typical board-level airflow and power dissipation conditions. AT29C256-70JI-T meets JEDEC JESD22-A104 temperature cycling requirements.
Does the AT29C256-70JI-T require a high-voltage programming supply?
No, the AT29C256-70JI-T operates exclusively from a single 5 V ± 10% supply for both read and program functions. Programming is initiated using 5V-only command sequences applied to standard address/data/control pins-no external 12 V or 21 V source is needed. Internal circuitry includes VCC sensing that inhibits programming if supply drops below ~3.8 V, ensuring safe operation during power transitions. AT29C256-70JI-T eliminates high-voltage generator components from system design.
How does the AT29C256-70JI-T indicate completion of a page program cycle?
The AT29C256-70JI-T provides two hardware-supported methods: DATA polling on I/O7 and toggle-bit detection on I/O6. During programming, reading the last loaded byte returns the complement of the data on I/O7; when programming completes, true data appears. Alternatively, I/O6 toggles between 0 and 1 on successive reads and stops toggling upon completion. Both methods work at any time during the 10 ms internal program period and require no additional control signals. AT29C256-70JI-T supports concurrent bus activity during polling.
Can the AT29C256-70JI-T be used as a direct replacement for standard SRAM in existing designs?
Yes, the AT29C256-70JI-T is functionally compatible with static RAM during read operations: it asserts data on I/O lines when CE and OE are low and WE is high, matching SRAM timing behavior. However, write operations differ fundamentally-AT29C256-70JI-T requires page-based programming with specific unlock sequences and timing. Direct SRAM replacement is viable only if the host system implements proper Flash-aware write protocols. AT29C256-70JI-T retains SRAM-like read interface simplicity while adding nonvolatility.
What package type is used for the AT29C256-70JI-T?
The AT29C256-70JI-T uses a 32-lead Plastic J-Leaded Chip Carrier (PLCC) package, identified by the "J" in the ordering code and documented as package type 32J in Atmel's datasheet. It features a square body with J-shaped leads, pin 1 marked by a corner notch, and NC connections on pins 1 and 17. This package complies with JEDEC MS-016 Variation AE and supports surface-mount reflow assembly. AT29C256-70JI-T's PLCC footprint differs from PDIP (28P6) and TSOP (28T) variants.
AT29C256-70JI-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:
- -40°C ~ 85°C (TC)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 32-PLCC (13.97x11.43)
AT29C256-70JI-T FAQ
1.How can I place an order for AT29C256-70JI-T through Aetrix?
Please submit a Request for Quotation (RFQ) for AT29C256-70JI-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 AT29C256-70JI-T reliable?
The price and inventory of AT29C256-70JI-T are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for AT29C256-70JI-T is usually 5 days.
3.What payment methods are accepted for AT29C256-70JI-T?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for AT29C256-70JI-T transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for AT29C256-70JI-T?
AT29C256-70JI-T orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your AT29C256-70JI-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 AT29C256-70JI-T?
For technical support, including AT29C256-70JI-T datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your AT29C256-70JI-T requirements.
6.How does Aetrix verify that AT29C256-70JI-T is sourced from the original manufacturer or authorized distributors?
All AT29C256-70JI-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 AT29C256-70JI-T meets industry standards.
7.What is the process for return or replacement of AT29C256-70JI-T?
All AT29C256-70JI-T units undergo pre-shipment inspection (PSI). If there is an issue with AT29C256-70JI-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 AT29C256-70JI-T part is unused and in its original packaging.
Return procedure for AT29C256-70JI-T:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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