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Microchip Technology AT29C256-90JI
- Part No.:
- AT29C256-90JI
- Manufacturer:
- Microchip Technology
- Category:
- Memory
- Package:
- 32-LCC (J-Lead)
- Datasheet:
-
AT29C256-90JI.pdf
- Description:
- IC FLASH 256KBIT PARALLEL 32PLCC
- Quantity:
- Payment:
- Shipping:
Inventory:1,811
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Product details
Overview
AT29C256-90JI from Atmel is a 256 Kbit (32K × 8) 5V-only Flash memory IC used for nonvolatile program/data storage in embedded microcontroller systems, industrial controllers, and legacy BIOS firmware. It delivers 90 ns read access time, supports page programming of 64-byte blocks, and operates across -40°C to +85°C with CMOS/TTL-compatible I/O.
For engineers reviewing the AT29C256-90JI datasheet, AT29C256-90JI pinout, AT29C256-90JI application, or AT29C256-90JI equivalent, key selection considerations include its 5V-only reprogramming architecture, hardware/software data protection, DATA polling and TOGGLE BIT end-of-write detection, and PLCC-32 packaging for through-hole industrial board designs.
Technical Context
The AT29C256-90JI implements a page-based Flash architecture where 64-byte writes are latched internally before simultaneous erasure and programming under internal timer control. Its dual-line chip enable (CE) and output enable (OE) logic enables bus contention avoidance during mixed read/write operations in shared-memory systems.
Hardware data protection includes VCC sense (<3.8 V inhibit), 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 access. Both mechanisms coexist without conflict and persist across power cycles.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Memory Size | 256 Kbit (32,768 × 8), sufficient for firmware images or configuration tables in 8-bit microcontroller systems |
| Read Access Time | 90 ns maximum - meets timing requirements for 11 MHz Z80 or 8051-based systems with no wait states |
| Page Program Time | 10 ms per 64-byte page - enables rapid field updates without full-chip erase overhead |
| VCC Supply | 5 V ± 10% - eliminates need for dedicated programming voltage rails in system design |
| Operating Temperature | -40°C to +85°C - qualified for industrial control, motor drives, and telecom line cards |
| Standby Current | 300 µA typical - reduces power budget in battery-backed or low-power sleep modes |
| Endurance | >10,000 write/erase cycles per sector - supports long-term logging or parameter tuning applications |
Pinout & Package
AT29C256-90JI is packaged in a 32-lead Plastic J-Leaded Chip Carrier (PLCC-32), pin-compatible with JEDEC MS-016 Variation AE. Pins 1 and 17 are No Connect (NC). The package supports through-hole mounting and provides thermal and mechanical robustness for industrial environments.
| 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 | CMOS/TTL-compatible 8-bit data path; I/O7 used for DATA polling, I/O6 for TOGGLE BIT status monitoring |
| CE | Chip Enable | Active-low device select; must be low for read, program, or erase; high-Z output when asserted high |
| OE | Output Enable | Active-low output control; used with CE to manage bus contention during reads |
| WE | Write Enable | Active-low control for byte load and page programming; timing-critical for 150 µs inter-byte loading window |
| VCC | Power Supply | +5 V ± 10% supply; powers core logic and charge pump circuitry for internal erase/program operations |
| GND | Ground Reference | Signal and power return; decoupling capacitor placement near pin 16 critical for stable programming |
Key Features
| Feature | Design Value |
|---|---|
| 5V-only reprogramming | Eliminates need for external 12 V programming supplies - simplifies power architecture and PCB layout |
| Internal address/data latches | 64-byte page buffer frees address/data bus during internal programming - enables background processing |
| DATA polling & TOGGLE BIT | Real-time, hardware-verified write completion detection without polling overhead or external timers |
| Hardware + software data protection | Dual-layer security prevents accidental writes during power-up/down or noise events - improves field reliability |
| CMOS standby current | 300 µA max at VCC = 5 V - extends battery life in maintenance mode or watchdog-triggered recovery sequences |
Applications
| Industrial PLC Firmware Storage | Legacy Embedded BIOS |
|---|---|
Use Scenario: Storing ladder logic programs and I/O configuration maps in programmable logic controllers deployed in factory automation. IC Role / Device Role / Timing Role: Nonvolatile code storage with fast random-access reads and infrequent field updates via serial host interface. Use Value: 90 ns read speed ensures deterministic scan-cycle timing; 10,000-cycle endurance supports decades of firmware revision management. | Use Scenario: Holding boot firmware and hardware initialization routines in x86-compatible embedded motherboards for medical imaging equipment. IC Role / Device Role / Timing Role: Primary boot ROM accessed directly by CPU during power-on reset sequence. Use Value: CMOS/TTL compatibility guarantees seamless integration with ISA-bus peripherals; -40°C to +85°C rating ensures operation in cooled chassis environments. |
| Telecom Line Card Configuration | Automated Test Equipment (ATE) Calibration Data |
Use Scenario: Storing port-specific configuration parameters and DSP filter coefficients in T1/E1 line interface units. IC Role / Device Role / Timing Role: Parameter memory mapped into processor address space for runtime read/write access. Use Value: Page-program capability allows selective update of individual channel settings without disrupting active traffic paths. | Use Scenario: Retaining calibration constants and self-test results across power cycles in benchtop multimeters and signal analyzers. IC Role / Device Role / Timing Role: Persistent data storage accessed only during startup or maintenance mode. Use Value: Hardware data protection prevents corruption during brown-out conditions; 300 µA standby current minimizes battery drain in portable ATE units. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar Flash memory applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| AM29LV256M-90EC | 3.3 V core with 5 V I/O tolerance; 90 ns read; 128 K × 16 organization | Requires level-shifting for pure 5 V systems; wider data bus suits 16-bit processors | Select if migrating to lower-voltage platforms or upgrading to 16-bit data paths |
| SST39VF256A-90-4C-NHE | 3.3 V supply; 90 ns read; 32K × 8; supports byte/page/sector/whole-chip erase | Not 5 V compatible; lacks hardware VCC-sense protection; requires different unlock sequences | Choose for new 3.3 V designs needing enhanced erase granularity and higher endurance (100K cycles) |
Compared with AM29LV256M-90EC and SST39VF256A-90-4C-NHE, the AT29C256-90JI offers native 5 V operation, integrated hardware write inhibition, and proven reliability in legacy industrial systems - making it the preferred choice for drop-in replacement or long-lifecycle maintenance.
Availability
AT29C256-90JI is available at Aetrix Electronics and suitable for industrial PLC firmware storage, legacy embedded BIOS, and telecom line card configuration requiring stable component supply over extended production lifecycles.
Supply support for AT29C256-90JI 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 U.S.-based semiconductor company specializing in microcontrollers, Flash memory, and secure authentication devices.
The AT29C256 product line was designed for 5V embedded systems requiring field-upgradable nonvolatile storage with industrial temperature resilience and simple in-system programming - targeting legacy industrial, telecom, and instrumentation markets.
FAQ
What is the operating temperature range for the AT29C256-90JI?
The AT29C256-90JI is rated for industrial operation from -40°C to +85°C. This range is validated per the manufacturer's DC and AC specifications and supports deployment in motor control cabinets, outdoor telecom enclosures, and factory-floor automation hardware where ambient temperatures exceed commercial-grade limits. The AT29C256-90JI maintains full 90 ns read timing and reliable page programming across this entire range.
Does the AT29C256-90JI require high-voltage programming signals?
No, the AT29C256-90JI uses 5V-only reprogramming - no external 12 V or 12.5 V programming voltage is needed. All commands (page program, chip erase, software protection enable/disable) are executed using standard 5 V logic levels applied to WE, CE, and OE pins. This eliminates the need for charge pumps or external HV generators, simplifying system design and reducing bill-of-materials cost. The AT29C256-90JI achieves internal high-voltage generation through on-chip circuitry powered solely by VCC.
How does DATA polling work on the AT29C256-90JI?
During a page program cycle, reading the last loaded byte from the AT29C256-90JI returns the complement of that data on I/O7 until programming completes. Once valid data appears on I/O7, the cycle is finished and the next operation may begin. This mechanism allows the host processor to poll I/O7 without halting other tasks - no external timer or interrupt is required. The AT29C256-90JI supports this behavior across all supported packages and temperature ranges.
Can the AT29C256-90JI be used as a direct replacement for the AT29C256-70JI?
Yes, the AT29C256-90JI is functionally identical to the AT29C256-70JI except for its 90 ns (vs. 70 ns) maximum read access time. Both share identical pinout, command set, voltage requirements, and timing for programming and erase operations. System-level compatibility depends on whether the host controller's read timing budget accommodates 90 ns - most 8051, Z80, and 68K-based designs do. The AT29C256-90JI remains fully interchangeable in existing PLCC-32 footprints.
What package type is used for the AT29C256-90JI?
The AT29C256-90JI is supplied in a 32-lead Plastic J-Leaded Chip Carrier (PLCC-32) package, compliant with JEDEC MS-016 Variation AE. Pin 1 is marked by a corner notch; pins 1 and 17 are No Connect (NC). This surface-mount-compatible through-hole package provides superior thermal dissipation and mechanical stability compared to PDIP variants, making it ideal for industrial PCBs subject to vibration or thermal cycling. The AT29C256-90JI's PLCC-32 footprint matches Atmel's documented 32J package outline.
AT29C256-90JI 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:
- 90 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)
AT29C256-90JI FAQ
1.How can I place an order for AT29C256-90JI through Aetrix?
Please submit a Request for Quotation (RFQ) for AT29C256-90JI 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 AT29C256-90JI reliable?
The price and inventory of AT29C256-90JI are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for AT29C256-90JI is usually 5 days.
3.What payment methods are accepted for AT29C256-90JI?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for AT29C256-90JI transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for AT29C256-90JI?
AT29C256-90JI orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your AT29C256-90JI 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 AT29C256-90JI?
For technical support, including AT29C256-90JI datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your AT29C256-90JI requirements.
6.How does Aetrix verify that AT29C256-90JI is sourced from the original manufacturer or authorized distributors?
All AT29C256-90JI 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 AT29C256-90JI meets industry standards.
7.What is the process for return or replacement of AT29C256-90JI?
All AT29C256-90JI units undergo pre-shipment inspection (PSI). If there is an issue with AT29C256-90JI, 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 AT29C256-90JI part is unused and in its original packaging.
Return procedure for AT29C256-90JI:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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