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Microchip Technology AT29C257-15JC
- Part No.:
- AT29C257-15JC
- Manufacturer:
- Microchip Technology
- Category:
- Memory
- Package:
- 32-LCC (J-Lead)
- Datasheet:
-
AT29C257-15JC.pdf
- Description:
- IC FLASH 256KBIT PARALLEL 32PLCC
- Quantity:
- Payment:
- Shipping:
Inventory:1,010
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Product details
Overview
AT29C257-15JC from Microchip Technology (formerly Atmel) is a 5-V-only, 256 Kbit (32K × 8) in-system reprogrammable Flash PEROM with 150 ns read access time, CMOS standby current of 300 µA, and page-program capability for 64-byte blocks. It serves as nonvolatile program/data storage in embedded controllers, BIOS firmware, and industrial control systems requiring field-upgradable memory.
For engineers reviewing the AT29C257-15JC datasheet, AT29C257-15JC pinout, AT29C257-15JC application, or AT29C257-15JC equivalent, key selection criteria include its 150 ns tACC timing grade, PLCC-32 package, software/hardware data protection, 10 ms page program cycle, and compatibility with 5V ±10% supply across commercial temperature range (0°C to 70°C).
Technical Context
The AT29C257-15JC implements a page-based Flash architecture where 64-byte writes are latched internally before simultaneous programming; address A6–A14 selects the page, while A0–A5 selects the byte within it. 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/erasure using 3-byte command sequences at fixed addresses (e.g., 5555H/2AAAH). Hardware protection includes VCC sense (<3.8 V inhibits programming) and noise filtering (<15 ns pulses ignored).
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Memory Size | 256 Kbit (32,768 × 8), organized for direct byte-addressable access in 8-bit microcontroller buses |
| Read Access Time (tACC) | 150 ns maximum - defines minimum clock period for reliable read cycles in 6–7 MHz bus systems |
| Page Program Time | 10 ms typical - determines firmware update latency per 64-byte sector in field upgrade routines |
| Supply Voltage | 5 V ±10% - compatible with legacy 5V TTL/CMOS logic without level-shifting circuitry |
| Standby Current (ISB1) | 300 µA max - enables low-power sleep mode in battery-backed or energy-constrained systems |
| Endurance | >10,000 write/erase cycles per sector - supports long-term field reprogramming in industrial controllers |
| Operating Temperature | 0°C to +70°C - qualified for commercial-grade embedded applications without extended thermal margin |
Pinout & Package
AT29C257-15JC is housed in a 32-lead Plastic Leaded Chip Carrier (PLCC) package with J-bend leads, designed for surface-mount assembly and socketed prototyping. Pin 1 is marked by a corner notch; the package footprint conforms to JEDEC MS-026AC.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| A0–A14 | Address Inputs | 15-bit address bus supporting full 32K-word addressing; A6–A14 used for page selection during programming |
| I/O0–I/O7 | Bidirectional Data Bus | 8-bit parallel interface compatible with 8051, Z80, and 68K family microcontrollers; supports DATA polling on I/O7 and TOGGLE bit on I/O6 |
| CE | Chip Enable | Active-low device select; must be low for read, program, or erase; high-Z outputs when high |
| OE | Output Enable | Active-low output control; used with CE to manage bus contention; must be high during programming |
| WE | Write Enable | Active-low control for byte loading and page programming initiation; timing-critical for 150 µs inter-byte load 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 12V programming voltage rails or charge pumps - simplifies power design and PCB layout |
| Internal 64-byte latches | Decouples host bus during internal programming; allows host CPU to perform other tasks while flash writes execute |
| Hardware data protection | VCC sense, 5 ms power-on delay, and noise filtering prevent spurious writes during brown-out or EMI events |
| Software data protection | User-configurable 3-byte unlock sequence (5555H/2AAAH/AAH) prevents accidental firmware corruption |
| DATA polling & TOGGLE bit | Two independent, hardware-supported methods (I/O7 complement, I/O6 toggle) for detecting program completion without timer overhead |
Applications
| Industrial PLC Firmware Storage | Embedded BIOS Boot Code |
|---|---|
Use Scenario: Storing ladder logic and configuration parameters in programmable logic controllers deployed in factory automation environments. IC Role / Device Role / Timing Role: Nonvolatile code and data storage with field-upgrade capability via RS-232 or CAN-based bootloader. Use Value: 10,000-cycle endurance ensures >10 years of scheduled firmware updates; 300 µA standby current reduces thermal load in sealed enclosures. | Use Scenario: Holding boot firmware and hardware initialization routines for x86-compatible industrial motherboards. IC Role / Device Role / Timing Role: Primary boot ROM mapped at reset vector; accessed during cold start before DRAM initialization. Use Value: 150 ns tACC meets Intel 486/Pentium-era timing requirements; pin-compatibility with AT29C010A enables drop-in capacity upgrades. |
| Medical Device Configuration Memory | Telecom Line Card Parameter Storage |
Use Scenario: Retaining calibration coefficients, user preferences, and safety-critical settings in portable diagnostic equipment. IC Role / Device Role / Timing Role: Secure parameter store with software data protection enabled to prevent unauthorized modification. Use Value: Dual protection (hardware VCC sense + software unlock) satisfies IEC 62304 Class C software safety requirements. | Use Scenario: Storing DSP filter coefficients and port-specific provisioning data on carrier-grade DSLAM line cards. IC Role / Device Role / Timing Role: Field-reprogrammable configuration memory accessible via JTAG or dedicated management MCU. Use Value: Page-program architecture enables selective coefficient updates without erasing entire configuration space - minimizing service downtime. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar Flash memory applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| AT29C040-15JC | 512 Kbit (64K × 8), same PLCC-32 package, 150 ns tACC, but requires 12V for chip erase | Larger capacity suits boot images with drivers; high-voltage erase limits use in 5V-only systems | Select only if additional memory space is required and 12V programming rail is available |
| SST39SF040-70-4C-NHE | 512 Kbit, 70 ns tACC, 3.3V/5V tolerant, supports byte-write (not page-only); different command set and pinout | Faster access and lower voltage operation, but not pin-compatible - requires PCB redesign | Prefer for new designs needing higher speed or dual-voltage support; not suitable for AT29C257-15JC drop-in replacement |
Compared with AT29C040-15JC and SST39SF040-70-4C-NHE, the AT29C257-15JC offers optimal balance of 5V-only operation, proven 10,000-cycle endurance, and direct compatibility with legacy 8-bit controller buses - making it ideal for cost-sensitive, field-upgradable commercial systems where board-level changes are prohibited.
Availability
AT29C257-15JC is available at Aetrix Electronics and suitable for industrial control systems, embedded BIOS implementations, medical device configuration storage, and telecom line card parameter retention requiring stable component supply across multi-year production cycles.
Supply support for AT29C257-15JC 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 acquired Atmel in 2016 and maintains full support for legacy Atmel Flash memory products including the AT29C series.
The AT29C257-15JC belongs to Atmel's early-generation 5V Flash PEROM product line, designed specifically for in-system reprogrammability in cost-sensitive commercial embedded systems without requiring external high-voltage programming circuitry.
FAQ
What is the operating temperature range for the AT29C257-15JC?
The AT29C257-15JC is rated for commercial operation from 0°C to +70°C. This range is defined by its "-15" speed grade suffix and "C" in the ordering code (AT29C257-15JC), and is validated per Microchip's DC and AC specifications. It is not rated for industrial (-40°C to +85°C) operation - that variant is designated AT29C257-15JI.
Does the AT29C257-15JC require a 12V programming voltage?
No, the AT29C257-15JC uses 5-V-only reprogramming. All program and erase functions are executed using standard 5V logic levels and specific software command sequences (e.g., 5555H/2AAAH/AAH). Unlike earlier EPROMs or some competing Flash devices, it contains no internal charge pump and does not accept or require 12V on any pin.
How is data protection implemented on the AT29C257-15JC?
The AT29C257-15JC implements dual-layer data protection: hardware protection (VCC sense below 3.8V disables programming, 5 ms power-on delay, and 15 ns noise filtering on WE/CE) and software protection (user-enabled 3-byte unlock sequence required before each program cycle). Both mechanisms are active simultaneously and independently.
What package type is used for the AT29C257-15JC?
The AT29C257-15JC is supplied in a 32-lead Plastic Leaded Chip Carrier (PLCC) package, identified by the "J" suffix in the ordering code and documented as package type "32J" in Microchip's datasheet. It features J-bend leads and a body size of 13.8 mm × 13.8 mm, with pin 1 located at the top-left corner adjacent to the package notch.
Can the AT29C257-15JC be used as a direct replacement for AT29C010A?
Yes - the AT29C257-15JC is explicitly stated as pin-compatible with AT29C010A and AT29C512 for easy system upgrades. Both share identical PLCC-32 pinouts, 5V-only operation, and compatible command protocols. However, memory size differs (AT29C010A = 1 Mbit, AT29C257-15JC = 256 Kbit), so address decoding and firmware image sizing must be verified.
AT29C257-15JC 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:
- 5V
- Operating Temperature:
- 0°C ~ 70°C (TC)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 32-PLCC (13.97x11.43)
AT29C257-15JC FAQ
1.How can I place an order for AT29C257-15JC through Aetrix?
Please submit a Request for Quotation (RFQ) for AT29C257-15JC 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 AT29C257-15JC reliable?
The price and inventory of AT29C257-15JC are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for AT29C257-15JC is usually 5 days.
3.What payment methods are accepted for AT29C257-15JC?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for AT29C257-15JC transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for AT29C257-15JC?
AT29C257-15JC orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your AT29C257-15JC 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 AT29C257-15JC?
For technical support, including AT29C257-15JC datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your AT29C257-15JC requirements.
6.How does Aetrix verify that AT29C257-15JC is sourced from the original manufacturer or authorized distributors?
All AT29C257-15JC 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 AT29C257-15JC meets industry standards.
7.What is the process for return or replacement of AT29C257-15JC?
All AT29C257-15JC units undergo pre-shipment inspection (PSI). If there is an issue with AT29C257-15JC, 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 AT29C257-15JC part is unused and in its original packaging.
Return procedure for AT29C257-15JC:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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