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Microchip Technology AT29C256-15PI
- Part No.:
- AT29C256-15PI
- Manufacturer:
- Microchip Technology
- Category:
- Memory
- Package:
- 28-DIP (0.600", 15.24mm)
- Datasheet:
-
AT29C256-15PI.pdf
- Description:
- IC FLASH 256KBIT PARALLEL 28DIP
- Quantity:
- Payment:
- Shipping:
Inventory:1,111
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Product details
Overview
AT29C256-15PI 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 modules. It delivers 150 ns read access time, supports page programming of 64-byte blocks in 10 ms, and operates across -40°C to +85°C with CMOS/TTL-compatible I/O.
For engineers reviewing the AT29C256-15PI datasheet, AT29C256-15PI pinout, AT29C256-15PI application, or AT29C256-15PI equivalent, key selection criteria include its 5V-only reprogramming architecture, hardware/software data protection, DATA polling and toggle-bit programming status detection, and PLCC-32 packaging for through-hole industrial PCBs.
Technical Context
The AT29C256-15PI implements a page-based Flash architecture where 64-byte pages are loaded via byte-load cycles using WE/CE-controlled latching, then internally erased and programmed under autonomous timing control. Its dual-line chip enable (CE) and output enable (OE) logic enables flexible bus interfacing without contention.
Hardware data protection includes VCC sense (<3.8 V inhibits programming), 5 ms power-on delay, noise filtering (<15 ns pulses rejected), and write-inhibit states enforced by OE high, CE high, or WE high. Software protection uses a three-step command sequence (AAh/55h/A0h) to enable/disable write access per page.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Memory Size | 256 Kbit (32,768 × 8), directly replaceable for 32K × 8 SRAM footprint in legacy designs |
| Read Access Time | 150 ns max - defines minimum CPU wait-state requirement for 80C51 or Z80-based systems |
| Page Program Time | 10 ms typical - enables firmware updates in batches without full-chip erase overhead |
| Endurance | >10,000 write/erase cycles per sector - supports field-upgradable control logic in PLCs |
| VCC Supply | 5 V ±10% - eliminates need for dedicated programming voltage rails in 5V system designs |
| Standby Current | 300 µA CMOS - enables low-power retention in battery-backed industrial monitoring nodes |
| Operating Temp | -40°C to +85°C - certified for deployment in motor drives, HVAC controllers, and factory automation |
Pinout & Package
AT29C256-15PI 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 thermal dissipation up to 275 mW at 70 ns access speed.
| 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 bit; I/O6 provides toggle-bit status feedback |
| CE | Chip Enable | Active-low global select; must be low for read, program, or erase; high forces high-Z outputs |
| OE | Output Enable | Active-low output gate; controls data assertion on I/O lines during read; high disables outputs |
| WE | Write Enable | Active-low control for byte loading and page programming initiation; synchronized with CE for latching |
| VCC | Power Supply | +5 V ±10% main supply; powers core logic and I/O buffers; enables internal VCC-sense protection |
| GND | Ground Reference | Signal and power return path; decoupling required within 10 mm of VCC pin per layout guidelines |
| NC / DC | No Connect / Don't Connect | Pins 1 and 17 are unconnected; must remain floating - no pull-up/down or routing allowed |
Key Features
| Feature | Design Value |
|---|---|
| 5V-only reprogramming | Eliminates need for 12 V programming supplies - simplifies power design and reduces BOM count |
| Page-based 64-byte programming | Reduces firmware update time vs. full-chip erase; enables partial code patching in field-deployed units |
| DATA polling & toggle-bit status | Allows real-time program completion detection without external timers or interrupts - critical for deterministic boot sequences |
| Hardware + software data protection | Prevents accidental writes during power transitions or noise events - ensures reliability in electrically noisy industrial environments |
| CMOS/TTL-compatible I/O | Direct interface with legacy 8051, 68K, and Z80 microcontrollers without level-shifting circuitry |
Applications
| Industrial PLC Firmware Storage | Legacy BIOS/UEFI Module |
|---|---|
|
Use Scenario: Storing ladder logic programs and configuration parameters in programmable logic controllers deployed in manufacturing lines. IC Role / Device Role / Timing Role: Nonvolatile program memory mapped into microcontroller address space; accessed via parallel bus with 150 ns timing margin. Use Value: Enables field firmware updates without chip replacement; >10,000 endurance supports decades of maintenance cycles in unattended operation. |
Use Scenario: Holding boot firmware and hardware initialization code in PC motherboards and embedded x86 platforms prior to UEFI transition. IC Role / Device Role / Timing Role: Read-only memory during POST; configured as 32K × 8 device with CE/OE decoding for CS0/CS1 bank selection. Use Value: 5V-only operation matches legacy ATX power rail; PLCC-32 package allows socketed replacement for BIOS recovery without soldering. |
| Motor Drive Parameter EEPROM | Medical Device Calibration Storage |
|
Use Scenario: Retaining motor tuning coefficients, safety limits, and runtime logs in AC servo drives operating in variable-frequency environments. IC Role / Device Role / Timing Role: Parameter storage accessed during startup and runtime via microcontroller SPI-to-parallel bridge or direct GPIO-banged interface. Use Value: Industrial temperature range (-40°C to +85°C) ensures stable operation near heat-generating IGBT modules; hardware write protection prevents corruption during EMI events. |
Use Scenario: Storing calibrated sensor offsets, gain tables, and regulatory compliance data in portable diagnostic equipment requiring traceable calibration history. IC Role / Device Role / Timing Role: Secure nonvolatile memory with software data protection enabled to prevent unauthorized parameter modification. Use Value: Dual protection (hardware VCC sense + software command lock) meets IEC 62304 Class C software requirements for data integrity in life-critical systems. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar Flash memory applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| AM29F256B-150EC | 48-pin TSOP; requires 12 V for programming; 150 ns access; no software data protection | Used in newer surface-mount designs; lacks integrated 5V-only programming and software lock | Select when board redesign supports 12 V programming rail and higher-density packaging is prioritized over field update simplicity |
| SST39SF256-15-4C-NHE | 32-pin PLCC; 5V-only; 150 ns access; supports both page and byte programming; no toggle-bit status | Offers byte-level writes but lacks toggle-bit for status polling - requires tighter timing coordination | Choose for applications needing single-byte updates without full-page reload, accepting added software complexity for status monitoring |
Compared with AM29F256B-150EC and SST39SF256-15-4C-NHE, the AT29C256-15PI uniquely combines 5V-only operation, software/hardware dual protection, and dual-status feedback (DATA polling + toggle-bit) in a through-hole PLCC-32 package - making it optimal for legacy industrial upgrades where reliability, ease of field service, and compatibility with existing 5V infrastructure are mandatory.
Availability
AT29C256-15PI is available at Aetrix Electronics and suitable for industrial PLCs, legacy BIOS modules, and medical calibration storage requiring stable component supply, long-lifecycle support, and through-hole manufacturability.
Supply support for AT29C256-15PI 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 industrial and automotive markets.
The AT29C256 product line was designed for 5V embedded systems requiring in-system reprogrammable nonvolatile storage with robust data integrity - targeting industrial control, telecom infrastructure, and legacy computing platforms.
FAQ
What is the maximum read access time specified for the AT29C256-15PI?
The AT29C256-15PI has a maximum read access time of 150 ns, as confirmed by its ordering suffix "-15" and AC Read Characteristics table. This value defines the worst-case delay from valid address/CE/OE setup to stable data on I/O0–I/O7, and directly determines compatible microprocessor wait-state configuration. The AT29C256-15PI maintains this timing across its full industrial temperature range (-40°C to +85°C) and 5 V ±10% supply.
Does the AT29C256-15PI require a high-voltage programming supply?
No, the AT29C256-15PI operates with 5 V ±10% only for both read and reprogramming functions - no 12 V or other high-voltage rail is needed. This is explicitly stated in its Features section and reinforced by Hardware Data Protection's VCC-sense threshold (3.8 V typical). The AT29C256-15PI uses internal charge pumps and 5V-only command sequences (e.g., AAh/55h/A0h) to perform page programming and chip erase.
How does the AT29C256-15PI indicate completion of a page programming cycle?
The AT29C256-15PI provides two hardware-supported methods: DATA polling on I/O7 (complement of last written byte until completion) and toggle-bit behavior on I/O6 (repeated toggling until programming ends). Both mechanisms are active during the 10 ms internal programming period and require no external timer. These features are integral to the AT29C256-15PI's architecture and validated in its AC Program Cycle and Data Polling Characteristic tables.
What package type is used for the AT29C256-15PI, and are there NC pins?
The AT29C256-15PI uses a 32-lead Plastic J-Leaded Chip Carrier (PLCC-32), per Ordering Information and Packaging Drawings. Pins 1 and 17 are designated NC (No Connect) and must remain unconnected - this is explicitly noted in the Pin Configurations diagram and confirmed in the PLCC mechanical drawing notes. The AT29C256-15PI's PLCC-32 footprint is mechanically and electrically identical to AT29C256-15JC but rated for industrial temperature range.
Can the AT29C256-15PI be used in systems requiring data write protection during power-up or noise events?
Yes, the AT29C256-15PI integrates dual-layer protection: hardware features (VCC sense <3.8 V, 5 ms power-on delay, WE/CE noise filtering <15 ns) and software protection (three-command enable/disable sequence). These are documented in separate Hardware and Software Data Protection sections and verified in Operating Modes tables. The AT29C256-15PI's protection remains active across power cycles unless explicitly disabled - ensuring data integrity in brown-out or EMI-prone industrial settings.
AT29C256-15PI Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Microchip Technology
- Series:
- -
- Package/Case:
- 28-DIP (0.600", 15.24mm)
- 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:
- Through Hole
- Supplier Device Package:
- 28-PDIP
AT29C256-15PI FAQ
1.How can I place an order for AT29C256-15PI through Aetrix?
Please submit a Request for Quotation (RFQ) for AT29C256-15PI 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 AT29C256-15PI reliable?
The price and inventory of AT29C256-15PI are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for AT29C256-15PI is usually 5 days.
3.What payment methods are accepted for AT29C256-15PI?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for AT29C256-15PI transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for AT29C256-15PI?
AT29C256-15PI orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your AT29C256-15PI 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 AT29C256-15PI?
For technical support, including AT29C256-15PI datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your AT29C256-15PI requirements.
6.How does Aetrix verify that AT29C256-15PI is sourced from the original manufacturer or authorized distributors?
All AT29C256-15PI 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 AT29C256-15PI meets industry standards.
7.What is the process for return or replacement of AT29C256-15PI?
All AT29C256-15PI units undergo pre-shipment inspection (PSI). If there is an issue with AT29C256-15PI, 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 AT29C256-15PI part is unused and in its original packaging.
Return procedure for AT29C256-15PI:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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