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Microchip Technology AT29C257-15JI
- Part No.:
- AT29C257-15JI
- Manufacturer:
- Microchip Technology
- Category:
- Memory
- Package:
- 32-LCC (J-Lead)
- Datasheet:
-
AT29C257-15JI.pdf
- Description:
- IC FLASH 256KBIT PARALLEL 32PLCC
- Quantity:
- Payment:
- Shipping:
Inventory:3,485
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Product details
Overview
AT29C257-15JI from Microchip Technology (formerly Atmel) is a 256 Kbit (32K × 8) 5-V-only in-system Flash PEROM memory IC used for firmware storage and code execution in embedded microcontroller systems. 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 industrial temperature range in a 32-lead PLCC package.
For engineers reviewing the AT29C257-15JI datasheet, AT29C257-15JI pinout, AT29C257-15JI application, or AT29C257-15JI equivalent, key selection criteria include its 5V-only reprogramming capability, hardware/software data protection, DATA polling and toggle-bit end-of-write detection, and pin-compatibility with AT29C010A and AT29C512 for legacy system upgrades.
Technical Context
The AT29C257-15JI implements a CMOS-based 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 bus contention avoidance during mixed read/write operations.
It supports three distinct operational modes: standard read (CE/OE low, WE high), byte load (WE or CE low with OE high), and software-controlled programming/erase using 6-byte command sequences at specific addresses (e.g., 5555H/2AAAH). Hardware protection includes VCC sense (<3.8 V inhibit), 5 ms power-on delay, and noise filtering on WE/CE inputs.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Memory Density | 256 Kbit (32,768 × 8), enabling full boot code or configuration storage in space-constrained designs |
| Read Access Time | 150 ns max - defines minimum CPU wait-state requirement for zero-wait-state interface at ≤6.67 MHz |
| Page Program Time | 10 ms typical - determines firmware update latency per 64-byte sector in field-upgrade scenarios |
| Endurance | >10,000 write/erase cycles - supports long-term field reprogramming in industrial controllers |
| VCC Supply | 5 V ±10% - eliminates need for dedicated programming voltage rails in 5V systems |
| Standby Current | 300 µA CMOS - enables low-power retention in battery-backed or energy-sensitive applications |
| Operating Temp | -40°C to +85°C - qualified for industrial-grade reliability without derating |
Pinout & Package
AT29C257-15JI is housed in a 32-lead Plastic Leaded Chip Carrier (PLCC) package with J-bend leads, footprint-compatible with industry-standard 32J socket layouts and reflow soldering profiles.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| A0–A14 | Address Inputs | 15-bit address bus supporting full 32K-word addressing; A6–A14 select page during programming |
| I/O0–I/O7 | Bidirectional Data Bus | 8-bit parallel interface compatible with 8051, Z80, and 68K family microcontrollers |
| CE | Chip Enable | Active-low global device select; must be low for read, program, or erase operations |
| OE | Output Enable | Active-low output gate; high-Z state prevents bus contention when disabled |
| WE | Write Enable | Active-low control for byte load and page programming initiation; timing-critical for 150 µs inter-byte window |
| NC | No Connect | Unbonded pin; must remain unconnected per design - no pull-up/down or routing required |
Key Features
| Feature | Design Value |
|---|---|
| 5-V-only reprogramming | Eliminates need for external 12 V programming supply, simplifying power architecture and reducing BOM cost |
| Hardware data protection | VCC sense, 5 ms power-on delay, and 15 ns noise filtering prevent spurious writes during brown-out or EMI events |
| Software data protection | User-configurable 3-byte unlock sequence (5555H/2AAAH/80H) prevents accidental firmware corruption |
| DATA polling & toggle-bit detection | I/O7 complement and I/O6 toggling provide real-time, non-intrusive write completion status without requiring timers or interrupts |
| Page-based programming | 64-byte internal latching allows host processor to release address/data bus after load, enabling concurrent background tasks |
Applications
| Industrial PLC Firmware Storage | Medical Device Bootloader Memory |
|---|---|
Use Scenario: Storing firmware images and calibration tables in programmable logic controllers deployed in factory automation environments. IC Role / Device Role / Timing Role: Nonvolatile code storage with in-system reprogrammability; provides deterministic 150 ns read latency for real-time task scheduling. Use Value: Enables remote firmware updates without hardware intervention while maintaining >10,000-cycle endurance under daily maintenance cycles. | Use Scenario: Holding certified bootloader and safety-critical initialization routines in Class II medical diagnostic equipment. IC Role / Device Role / Timing Role: Secure, tamper-resistant firmware repository with hardware/software write protection and industrial temperature operation. Use Value: Meets IEC 62304 traceability requirements via controlled programming sequences and reliable 300 µA standby current for battery backup. |
| Automotive ECU Configuration Memory | Legacy Industrial Instrumentation Upgrade |
Use Scenario: Storing vehicle-specific calibration maps and emission control parameters in engine control units operating in under-hood environments. IC Role / Device Role / Timing Role: High-reliability configuration storage with -40°C to +85°C qualification and 5V-only interface matching legacy ECU power domains. Use Value: Supports field recalibration via service tools without requiring voltage translators or redesign of existing 5V MCU interfaces. | Use Scenario: Replacing obsolete EPROMs (e.g., 27C256) in aging test equipment and process controllers with minimal PCB modification. IC Role / Device Role / Timing Role: Pin-compatible Flash drop-in replacement offering faster 150 ns access vs. 250 ns EPROMs and eliminating UV erasers. Use Value: Reduces maintenance downtime by enabling in-situ firmware updates and eliminating quartz-window handling and UV exposure risks. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar Flash memory applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| AT29C256-15JI | 128 Kbit (16K × 8) density; identical timing, package, and command set | Limited to smaller firmware images; insufficient for full bootloader + application binaries in complex systems | Select when memory footprint is constrained and 128 Kbit suffices - reduces cost without changing layout or firmware driver |
| SST39SF200A-70-4C-NHE | 2 Mbit density, 70 ns access, 3.3 V core (5 V tolerant I/O), different command protocol | Requires voltage translation or 3.3 V domain integration; not pin-compatible; needs driver rewrite | Choose for higher-density, lower-power systems where board redesign and firmware adaptation are acceptable |
Compared with AT29C256-15JI, the AT29C257-15JI doubles capacity while retaining identical pinout and timing - ideal for firmware expansion without layout change. Versus SST39SF200A, it avoids 3.3 V domain migration but trades off density and active power for proven 5V industrial compatibility.
Availability
AT29C257-15JI is available at Aetrix Electronics and suitable for industrial PLCs, medical diagnostics equipment, automotive ECUs, and legacy instrumentation requiring stable component supply across extended product lifecycles.
Supply support for AT29C257-15JI 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
Microchip Technology is a U.S.-based semiconductor company specializing in microcontrollers, analog devices, and nonvolatile memory solutions for industrial, automotive, and consumer applications.
The AT29C257-15JI belongs to Microchip's legacy Flash PEROM product line, designed specifically for in-system reprogrammability in 5V embedded systems requiring robust data retention and field-upgradable firmware storage.
FAQ
What is the maximum read access time specified for the AT29C257-15JI?
The AT29C257-15JI has a maximum read access time (tACC) of 150 ns, measured under industrial temperature conditions (-40°C to +85°C) and 5 V ±10% supply. This value ensures compatibility with microcontrollers requiring ≤6.67 MHz bus timing and defines the worst-case delay between address assertion and valid data on I/O0–I/O7.
Does the AT29C257-15JI require a high-voltage programming supply?
No, the AT29C257-15JI operates with 5 V only for both read and reprogramming functions. It uses internally generated high-voltage charge pumps and software command sequences - eliminating external 12 V supplies and simplifying system-level power design compared to older EPROM or EEPROM technologies.
How does hardware data protection work on the AT29C257-15JI?
Hardware data protection on the AT29C257-15JI includes four mechanisms: (1) VCC sense circuitry inhibits programming if supply drops below ~3.8 V; (2) automatic 5 ms power-on delay before accepting commands; (3) program inhibition when OE is low or CE/WE states violate valid timing windows; and (4) 15 ns noise filtering on WE/CE pins to reject EMI-induced glitches.
Can the AT29C257-15JI be used as a direct replacement for AT29C010A or AT29C512?
Yes, the AT29C257-15JI is explicitly stated as pin-compatible with AT29C010A (1 Mbit) and AT29C512 (64 Kbit) for easy system upgrades. While densities differ, shared pinout, command structure, and 5V-only operation allow reuse of PCB layout and firmware drivers - though address decoding logic may require adjustment for the 32K-word boundary.
What methods does the AT29C257-15JI provide to detect end-of-program completion?
The AT29C257-15JI offers two hardware-supported methods: DATA polling (monitoring complement-to-data on I/O7 during programming) and toggle-bit detection (observing I/O6 toggling until completion). Both operate without halting the host processor and are fully supported in the AT29C257-15JI's timing specifications and AC waveforms.
AT29C257-15JI 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)
AT29C257-15JI FAQ
1.How can I place an order for AT29C257-15JI through Aetrix?
Please submit a Request for Quotation (RFQ) for AT29C257-15JI 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 AT29C257-15JI reliable?
The price and inventory of AT29C257-15JI are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for AT29C257-15JI is usually 5 days.
3.What payment methods are accepted for AT29C257-15JI?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for AT29C257-15JI transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for AT29C257-15JI?
AT29C257-15JI orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your AT29C257-15JI 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 AT29C257-15JI?
For technical support, including AT29C257-15JI datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your AT29C257-15JI requirements.
6.How does Aetrix verify that AT29C257-15JI is sourced from the original manufacturer or authorized distributors?
All AT29C257-15JI 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 AT29C257-15JI meets industry standards.
7.What is the process for return or replacement of AT29C257-15JI?
All AT29C257-15JI units undergo pre-shipment inspection (PSI). If there is an issue with AT29C257-15JI, 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 AT29C257-15JI part is unused and in its original packaging.
Return procedure for AT29C257-15JI:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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