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Microchip Technology AT29C256-15JI
- Part No.:
- AT29C256-15JI
- Manufacturer:
- Microchip Technology
- Category:
- Memory
- Package:
- 32-LCC (J-Lead)
- Datasheet:
-
AT29C256-15JI.pdf
- Description:
- IC FLASH 256KBIT PARALLEL 32PLCC
- Quantity:
- Payment:
- Shipping:
Inventory:4,663
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Product details
Overview
AT29C256-15JI 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 150 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) with CMOS/TTL-compatible I/Os.
For engineers reviewing the AT29C256-15JI datasheet, AT29C256-15JI pinout, AT29C256-15JI application, or AT29C256-15JI equivalent, key selection criteria include its 5V-only operation, hardware/software data protection, DATA polling and toggle-bit program status detection, and PLCC-32J package compatibility with legacy board layouts.
Technical Context
The AT29C256-15JI implements a nonvolatile Flash architecture with internal address/data latches for 64-byte page loading and an autonomous internal timer for erase-and-program execution. Its dual-line chip enable (CE) and output enable (OE) control enables flexible bus interfacing without contention.
It supports three distinct operational modes: standard read (CE/OE low, WE high), byte load (WE or CE pulse with OE high), and software-controlled page program or chip erase using six-byte command sequences at specific addresses (e.g., 5555H/2AAAH). Hardware protection includes VCC sense (<3.8 V inhibits programming) and noise filtering on WE/CE inputs.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Memory Size | 256 Kbit (32,768 × 8), sufficient for boot code or configuration data in microcontroller systems |
| Read Access Time | 150 ns maximum - defines minimum CPU wait-state requirement for direct memory-mapped access |
| Page Program Time | 10 ms per 64-byte page - enables rapid field updates without full-chip erasure |
| Endurance | >10,000 write/erase cycles per sector - supports long-term firmware revision management |
| Supply Voltage | 5 V ± 10% - eliminates need for dedicated programming voltage rails |
| Standby Current | 300 µA CMOS - enables low-power retention in battery-backed systems |
| Operating Temperature | −40°C to +85°C - qualified for industrial control and automotive under-hood environments |
Pinout & Package
AT29C256-15JI is supplied in a 32-lead Plastic J-Leaded Chip Carrier (PLCC-32J) package with gull-wing leads, JEDEC MS-016 compliant, and pin 1 marked by corner chamfer. Pins 1 and 17 are no-connect (NC) and must remain unconnected per datasheet.
| 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 used for DATA polling, I/O6 for toggle-bit status monitoring |
| CE | Chip Enable | Active-low global device select; required low for read, program, or erase operations |
| OE | Output Enable | Active-low output control; must be high during programming to disable outputs and prevent bus conflict |
| WE | Write Enable | Active-low control for byte load and program initiation; timing-critical for 150 µs inter-byte loading window |
| VCC | Power Supply | +5 V ± 10% main supply; powers core logic and memory array |
| GND | Ground Reference | Signal and power return path; decoupling capacitor placement critical near pin 16 |
| NC (Pins 1, 17) | No Connect | Unbonded pins; must be left floating - no PCB trace or solder mask opening required |
Key Features
| Feature | Design Value |
|---|---|
| 5V-only reprogramming | Eliminates need for external 12 V programming supply, simplifying system power architecture |
| Internal 64-byte address/data latch | Offloads CPU during page programming, freeing address/data bus for concurrent tasks |
| Hardware data protection | VCC sense, power-on delay, and noise filtering prevent accidental writes during brown-out or EMI events |
| Software data protection | Three-byte unlock sequence (5555H/2AAAH/A0H) required before each program cycle - prevents unintended firmware corruption |
| DATA polling & toggle-bit status | Enables deterministic end-of-program detection without fixed delays or external timers |
Applications
| Industrial PLC Firmware Storage | Legacy Embedded Controller Boot Memory |
|---|---|
Use Scenario: Storing firmware images and configuration parameters in programmable logic controllers deployed in factory automation environments. IC Role / Device Role / Timing Role: Nonvolatile boot memory mapped to microcontroller address space; provides 150 ns read access for deterministic startup timing. Use Value: Industrial temperature rating (−40°C to +85°C) and >10,000 endurance cycles ensure reliable field updates over 10+ years of operation. | Use Scenario: Replacing EPROMs in legacy 8-bit/16-bit microcontroller systems where socketed, field-upgradable memory is required. IC Role / Device Role / Timing Role: Pin-compatible Flash replacement for 27C256 EPROMs; uses identical PLCC-32J footprint and 5 V supply. Use Value: Eliminates UV eraser dependency and enables in-system firmware patches without board removal. |
| Medical Device Configuration Storage | Automotive Diagnostic Module Code Storage |
Use Scenario: Holding calibration tables and safety-critical configuration data in portable diagnostic equipment subject to periodic regulatory updates. IC Role / Device Role / Timing Role: Secure nonvolatile storage with software data protection enabled to prevent unauthorized parameter modification. Use Value: Three-byte unlock sequence ensures only authenticated host firmware can initiate reprogramming - meeting IEC 62304 software lifecycle requirements. | Use Scenario: Storing OBD-II diagnostic routines and vehicle-specific calibration maps in aftermarket scan tools operating under under-hood thermal stress. IC Role / Device Role / Timing Role: Read-intensive Flash memory accessed via microcontroller's external bus interface during active diagnostics. Use Value: 300 µA standby current extends battery life between sessions; 150 ns access avoids CPU wait states during real-time data streaming. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar Flash memory applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| AM29F200BT-120EC | 4 Mbit capacity, 120 ns access, 3 V/5 V tolerant, requires VPP = 12 V for programming | Higher density but incompatible voltage scheme; not 5V-only | Select only if system already supports 12 V programming rail and requires >256 Kbit |
| SST39SF200A-70-4C-NHE | 2 Mbit, 70 ns access, 3 V operation, no 5 V support, different command set | Lower voltage, faster access, but incompatible supply and protection logic | Not suitable for 5 V systems; requires redesign of power and firmware drivers |
Compared with AM29F200BT-120EC and SST39SF200A-70-4C-NHE, the AT29C256-15JI uniquely supports true 5V-only in-system programming with integrated hardware/software protection - making it the only drop-in replacement for legacy 27C256-based designs requiring zero PCB changes.
Availability
AT29C256-15JI is available at Aetrix Electronics and suitable for industrial PLC firmware storage, legacy embedded controller boot memory, and medical device configuration storage requiring stable component supply and long-lifecycle support.
Supply support for AT29C256-15JI 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 engineered for cost-sensitive, 5V-based embedded systems requiring field-upgradable nonvolatile memory with industrial temperature resilience and simple programming interfaces.
FAQ
What is the maximum read access time specified for the AT29C256-15JI?
The AT29C256-15JI has a maximum read access time (tACC) of 150 ns, as confirmed in the AC Read Characteristics table of the official Atmel datasheet (Rev. 0046O–FLASH–06/02). This value applies across the full industrial temperature range (−40°C to +85°C) and 5 V ± 10% supply, and directly determines the minimum wait-state configuration needed when interfacing with microcontrollers or FPGAs.
Does the AT29C256-15JI require a high-voltage programming supply?
No, the AT29C256-15JI does not require a high-voltage programming supply. It is a 5V-only Flash memory: all programming, erasing, and reading operations use only the standard VCC supply (5 V ± 10%). The device uses internal charge pumps and software command sequences - eliminating the need for external 12 V (VPP) rails common in older EPROMs and some competing Flash devices.
How is program completion detected on the AT29C256-15JI?
Program completion on the AT29C256-15JI is detected using either DATA polling (monitoring complement-to-data on I/O7) or the toggle-bit method (observing toggling on I/O6). Both methods are fully supported and characterized in the datasheet. DATA polling allows single-pin status checking, while the toggle-bit method provides a secondary, independent verification channel - both usable at any point during the 10 ms internal programming cycle.
What package type is used for the AT29C256-15JI?
The AT29C256-15JI is packaged in a 32-lead Plastic J-Leaded Chip Carrier (PLCC-32J), as explicitly stated in the Ordering Information table and Packaging Information section of the Atmel datasheet. Pins 1 and 17 are designated as no-connect (NC) and must remain unconnected on the PCB layout.
Is software data protection enabled by default on the AT29C256-15JI?
No, software data protection is disabled by default on the AT29C256-15JI when shipped from Atmel. It must be explicitly enabled using the documented three-byte unlock sequence (write AAH to 5555H, 55H to 2AAAH, then A0H to 5555H). Once enabled, all subsequent programming operations require repeating this sequence - providing robust protection against accidental writes during power transitions or firmware bugs.
AT29C256-15JI 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:
- 150 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)
AT29C256-15JI FAQ
1.How can I place an order for AT29C256-15JI through Aetrix?
Please submit a Request for Quotation (RFQ) for AT29C256-15JI 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 AT29C256-15JI reliable?
The price and inventory of AT29C256-15JI are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for AT29C256-15JI is usually 5 days.
3.What payment methods are accepted for AT29C256-15JI?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for AT29C256-15JI transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for AT29C256-15JI?
AT29C256-15JI orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your AT29C256-15JI 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 AT29C256-15JI?
For technical support, including AT29C256-15JI datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your AT29C256-15JI requirements.
6.How does Aetrix verify that AT29C256-15JI is sourced from the original manufacturer or authorized distributors?
All AT29C256-15JI 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 AT29C256-15JI meets industry standards.
7.What is the process for return or replacement of AT29C256-15JI?
All AT29C256-15JI units undergo pre-shipment inspection (PSI). If there is an issue with AT29C256-15JI, 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 AT29C256-15JI part is unused and in its original packaging.
Return procedure for AT29C256-15JI:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
AT29C256-15JI Tags
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AT24C02C-XHM-T
Microchip Technology
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AT21CS01-STUM10-T
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M24C02-FMC6TG
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AT24CS02-SSHM-T
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93LC46BT-I/OT
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24LC01BT-I/SN
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24AA02UIDT-I/OT
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