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Microchip Technology AT29C257-70JI
- Part No.:
- AT29C257-70JI
- Manufacturer:
- Microchip Technology
- Category:
- Memory
- Package:
- 32-LCC (J-Lead)
- Datasheet:
-
AT29C257-70JI.pdf
- Description:
- IC FLASH 256KBIT PARALLEL 32PLCC
- Quantity:
- Payment:
- Shipping:
Inventory:3,535
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Product details
Overview
AT29C257-70JI from Microchip Technology (formerly Atmel) is a 5-V-only, in-system reprogrammable Flash PEROM with 256 Kbit (32K × 8) capacity, 70 ns read access time, and page-program architecture supporting 64-byte loads. It operates across -40°C to +85°C and delivers 50 mA active current with 300 µA CMOS standby current, suited for industrial firmware storage in microcontroller-based systems.
For engineers reviewing the AT29C257-70JI datasheet, AT29C257-70JI pinout, AT29C257-70JI application, or AT29C257-70JI equivalent, key selection criteria include its 70 ns read timing, software/hardware data protection, page-erase-and-program capability, and PLCC-32J package compatibility with legacy AT29C010A/AT29C512 designs.
Technical Context
The AT29C257-70JI implements a nonvolatile CMOS Flash memory architecture with internal latching for 64-byte page programming and automatic erase-before-write sequencing. Its dual-line control (CE/OE) enables bus contention avoidance during read cycles, while DATA polling on I/O7 and toggle-bit detection on I/O6 provide deterministic program cycle completion signaling.
Hardware data protection includes VCC sense (<3.8 V inhibition), 5 ms power-on delay, and noise filtering (<15 ns pulse rejection); software protection uses a three-command sequence (5555H/2AAAH/AAH) to enable/disable write access. The device supports both hardware and software product identification modes returning Manufacturer Code 1Fh and Device Code DCh.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Memory Size | 256 Kbit (32,768 × 8), enabling full firmware image storage for mid-complexity MCUs |
| Read Access Time | 70 ns max - meets timing requirements for 14 MHz bus interfaces without wait states |
| Page Program Time | 10 ms typical - allows rapid field updates of 64-byte firmware segments |
| VCC Supply | 5 V ± 10% - compatible with standard logic rails; no auxiliary voltage required |
| Operating Temperature | -40°C to +85°C - qualified for industrial ambient environments |
| Endurance | >10,000 write/erase cycles per sector - supports long-term field upgradeability |
| Standby Current | 300 µA CMOS - minimizes quiescent power in always-on embedded controllers |
Pinout & Package
AT29C257-70JI is housed in a 32-lead Plastic Leaded Chip Carrier (PLCC) package with J-bend leads, pin-compatible with AT29C010A and AT29C512 for drop-in upgrades in existing PCB layouts.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| A0–A14 | Address Inputs | 15-bit address bus supporting full 32K-word addressing; A0–A5 select byte within 64-byte page |
| CE | Chip Enable | Active-low chip select; must be low with OE low and WE high for read access |
| OE | Output Enable | Active-low output control; high-Z state when asserted high, preventing bus contention |
| WE | Write Enable | Active-low write strobe; controls byte load and initiates page programming when CE is low |
| I/O0–I/O7 | Bi-directional Data Bus | 8-bit parallel interface; carries input data during programming and output data during reads |
| NC | No Connect | Unbonded pin; must remain unconnected per design rules |
Key Features
| Feature | Design Value |
|---|---|
| 5-V-only reprogramming | Eliminates need for 12 V programming supply, simplifying power design and reducing BOM count |
| Internal 64-byte page latch | Decouples host bus during 10 ms internal programming, enabling concurrent system operations |
| DATA polling (I/O7) | Enables real-time status monitoring without timer overhead or interrupt latency penalties |
| Dual data protection | Hardware (VCC sense, noise filter) and software (3-command lock) prevent accidental writes during power transitions or noise events |
| Software chip erase | 6-byte command sequence erases entire array in 10 ms, avoiding external high-voltage circuitry |
Applications
| Industrial PLC Firmware Storage | Medical Device Bootloader Memory |
|---|---|
|
Use Scenario: Storing firmware images and configuration parameters in programmable logic controllers deployed in factory automation environments with wide temperature swings. IC Role / Device Role / Timing Role: Nonvolatile code storage with 70 ns read access ensuring deterministic boot timing and real-time task loading. Use Value: Industrial temperature rating (-40°C to +85°C) and >10,000 endurance cycles support 15+ year field deployment without replacement. |
Use Scenario: Holding certified bootloader and safety-critical initialization routines in Class II medical equipment requiring traceable, tamper-resistant firmware storage. IC Role / Device Role / Timing Role: Secure, software-protected Flash memory where hardware data protection prevents corruption during power-up/down sequences. Use Value: Dual protection (hardware VCC sense + software 3-command lock) ensures firmware integrity compliance with IEC 62304 clause 5.5.3. |
| Automotive Body Control Module | Legacy Industrial Instrumentation Upgrade |
|
Use Scenario: Storing calibration tables and CAN protocol stacks in under-hood body control units exposed to thermal cycling and EMI. IC Role / Device Role / Timing Role: Page-programmable Flash with 10 ms erase/program cycles enabling over-the-air parameter updates via diagnostic interfaces. Use Value: 300 µA standby current extends battery life during vehicle sleep mode; PLCC-32J package withstands mechanical shock per AEC-Q200. |
Use Scenario: Replacing obsolete EPROMs in aging test equipment and process controllers without board redesign. IC Role / Device Role / Timing Role: Pin-compatible Flash upgrade for AT29C010A/AT29C512 sockets, retaining same footprint and signal routing. Use Value: Direct substitution reduces NRE cost and qualification time; 5-V-only operation eliminates UV-eraser dependency and high-voltage programming fixtures. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar Flash memory applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SST39VF200A-70-4C-NHE | 4 Mbit (256K × 16), 70 ns access, 3.3 V supply only; no 5 V compatibility | Requires level-shifting or rail change; not suitable for 5 V-only legacy systems | Select only if migrating to 3.3 V architecture and needing wider data bus |
| MX29LV256EITI-70G | 32 Mbit (2M × 16), 70 ns access, 3.0–3.6 V supply; supports CFI query mode | Larger density but incompatible voltage domain and command set; requires firmware rewrite | Choose for new designs needing higher capacity and JEDEC-standardized interface |
Compared with SST39VF200A-70-4C-NHE and MX29LV256EITI-70G, the AT29C257-70JI uniquely maintains 5 V-only operation, PLCC-32J pinout, and software/hardware protection features essential for drop-in industrial upgrades without voltage rail changes or layout modification.
Availability
AT29C257-70JI is available at Aetrix Electronics and suitable for industrial PLC firmware storage, medical device bootloader memory, and automotive body control module applications requiring stable component supply across extended temperature ranges and long production lifecycles.
Supply support for AT29C257-70JI 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 continues to manufacture, qualify, and support legacy Atmel Flash products including the AT29C257 family under its broad analog and memory portfolio.
The AT29C257-70JI belongs to Atmel's industrial-grade Flash PEROM product line, designed specifically for in-system reprogrammability in resource-constrained embedded systems where 5 V compatibility, pin compatibility with legacy ROMs, and robust data protection are mandatory.
FAQ
What is the operating temperature range for the AT29C257-70JI?
The AT29C257-70JI is rated for industrial operation from -40°C to +85°C. This specification is confirmed in the Ordering Information table (page 4-115) and applies specifically to the "-JI" suffix variant. The device maintains full DC and AC performance across this range, including 70 ns read access time and 300 µA standby current, making it suitable for deployment in harsh environmental conditions without derating.
Does the AT29C257-70JI require high-voltage programming?
No, the AT29C257-70JI uses 5-V-only reprogramming and does not require external high-voltage supplies. All programming and erase operations are initiated using standard 5 V logic-level commands - such as the 5555H/2AAAH/AAH unlock sequence - eliminating the need for dedicated 12 V programming circuits. This feature is explicitly stated in the Features section and verified in the Software Data Protection Enable Algorithm diagram (page 4-111).
How is end-of-program detection implemented in the AT29C257-70JI?
The AT29C257-70JI provides two hardware-supported methods: DATA polling on I/O7 and toggle-bit detection on I/O6. During programming, reading the last loaded byte returns the complement on I/O7 until completion; I/O6 toggles between 0 and 1 until the cycle finishes. Both mechanisms are documented in Sections 4-112 and 4-113 and require no external timers or firmware delays, enabling deterministic host synchronization.
Is the AT29C257-70JI pin-compatible with other Atmel Flash devices?
Yes, the AT29C257-70JI is explicitly pin-compatible with AT29C010A and AT29C512, as confirmed in the Features section and Pin Configurations diagram (page 4-105). All three devices use the same PLCC-32J package and identical pin functions (A0–A14, CE, OE, WE, I/O0–I/O7), enabling direct socket replacement in legacy designs without PCB modification.
What data protection mechanisms does the AT29C257-70JI support?
The AT29C257-70JI implements dual-layer data protection: hardware-based (VCC sense below 3.8 V inhibits programming, 5 ms power-on delay, noise filtering for <15 ns pulses) and software-based (3-command unlock sequence: 5555H/2AAAH/AAH). Both are detailed in the Device Operation section (pages 4-105–4-106), and software protection remains active across power cycles unless explicitly disabled.
AT29C257-70JI 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:
- 70 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)
AT29C257-70JI FAQ
1.How can I place an order for AT29C257-70JI through Aetrix?
Please submit a Request for Quotation (RFQ) for AT29C257-70JI 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 AT29C257-70JI reliable?
The price and inventory of AT29C257-70JI are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for AT29C257-70JI is usually 5 days.
3.What payment methods are accepted for AT29C257-70JI?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for AT29C257-70JI transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for AT29C257-70JI?
AT29C257-70JI orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your AT29C257-70JI 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 AT29C257-70JI?
For technical support, including AT29C257-70JI datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your AT29C257-70JI requirements.
6.How does Aetrix verify that AT29C257-70JI is sourced from the original manufacturer or authorized distributors?
All AT29C257-70JI 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 AT29C257-70JI meets industry standards.
7.What is the process for return or replacement of AT29C257-70JI?
All AT29C257-70JI units undergo pre-shipment inspection (PSI). If there is an issue with AT29C257-70JI, 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 AT29C257-70JI part is unused and in its original packaging.
Return procedure for AT29C257-70JI:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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