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Microchip Technology AT29C257-90JI
- Part No.:
- AT29C257-90JI
- Manufacturer:
- Microchip Technology
- Category:
- Memory
- Package:
- 32-LCC (J-Lead)
- Datasheet:
-
AT29C257-90JI.pdf
- Description:
- IC FLASH 256KBIT PARALLEL 32PLCC
- Quantity:
- Payment:
- Shipping:
Inventory:2,807
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Product details
Overview
AT29C257-90JI 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 configuration in embedded controllers. It delivers 90 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 with CMOS standby current <300 µA.
For engineers reviewing the AT29C257-90JI datasheet, AT29C257-90JI pinout, AT29C257-90JI application, or AT29C257-90JI equivalent, key selection criteria include its 5V-only reprogramming capability, hardware/software data protection, DATA polling and toggle-bit program status detection, and PLCC-32 package compatibility with legacy AT29C010A/AT29C512 designs.
Technical Context
The AT29C257-90JI implements a nonvolatile Flash architecture with internal address/data latches for 64-byte page loading, automatic erase-and-program sequencing, and dual-line chip/output enable control to prevent bus contention. Its operation requires no external high-voltage supply - all commands execute using standard 5V logic levels.
It supports three primary operational modes: Read (CE/OE low, WE high), Byte Load (for page data or command entry), and Program (page-based with software-controlled data protection). End-of-program detection is implemented via I/O7 DATA polling or I/O6 toggle-bit monitoring, both usable at any point during the 10 ms internal write cycle.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Memory Size | 256 Kbit (32,768 × 8), organized as 32K words × 8 bits - directly replaces 32K × 8 EPROMs without address decoding changes. |
| Read Access Time | 90 ns max - ensures compatibility with 11 MHz bus timing in microcontroller systems without wait-state insertion. |
| Page Program Time | 10 ms typical - enables fast field firmware updates with minimal system downtime per 64-byte sector. |
| Supply Voltage | 5 V ± 10% - eliminates need for dedicated programming voltage regulators in 5V systems. |
| Standby Current | 300 µA CMOS - reduces power budget impact in battery-backed or low-power sleep modes. |
| Endurance | >10,000 write/erase cycles per sector - supports long-term field-upgradable applications like industrial HMI or telecom node configuration. |
| Operating Temp | -40°C to +85°C - qualified for industrial-grade embedded environments including motor drives and PLC modules. |
Pinout & Package
AT29C257-90JI 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 during programming. |
| I/O0–I/O7 | Bidirectional Data Bus | 8-bit parallel interface compatible with TTL/CMOS logic; carries data during read, byte load, and program operations. |
| CE | Chip Enable | Active-low chip select; must be low for read, program, or byte load; high disables outputs and enters standby mode. |
| OE | Output Enable | Active-low output control; used with CE to gate data onto bus; high places outputs in high-impedance state. |
| WE | Write Enable | Active-low control for byte loading and program initiation; timing-critical for 150 µs inter-byte window in page programming. |
| NC | No Connect | Unbonded pin; must remain unconnected on PCB to avoid unintended coupling or leakage paths. |
Key Features
| Feature | Design Value |
|---|---|
| 5-V-only reprogramming | Eliminates requirement for 12V programming supplies or charge pumps - simplifies power design and reduces BOM count. |
| Hardware data protection | VCC sense (<3.8V inhibits programming), 5 ms power-on delay, and noise filtering (<15 ns pulses ignored) prevent accidental writes during brown-out or EMI events. |
| Software data protection | User-configurable 3-byte unlock sequence (5555H/2AAAH/80H) required before each program cycle - prevents unauthorized firmware modification. |
| DATA polling & toggle-bit detection | I/O7 complement-read and I/O6 toggling provide real-time, non-blocking program status feedback without requiring timers or interrupts. |
| Page-based programming | 64-byte internal latching allows host processor to release address/data bus after each byte load - enables concurrent background processing during 10 ms write cycle. |
Applications
| Industrial PLC Firmware Storage | Automotive ECU 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 boot memory providing deterministic 90 ns read access to instruction fetches from microcontroller during cold start and runtime updates. Use Value: Industrial temperature rating (-40°C to +85°C) and >10,000 endurance cycles ensure reliable operation over 10+ years in unventilated control cabinets. | Use Scenario: Holding bootloader code and secure update partitions in automotive engine control units subject to ISO 16750-2 electrical transients. IC Role / Device Role / Timing Role: In-system reprogrammable Flash memory enabling OTA firmware patches without disassembly or external programmers. Use Value: Hardware data protection (VCC sense, noise filtering) prevents corruption during vehicle cranking or load-dump events. |
| Medical Device Configuration Storage | Networking Equipment Parameter Memory |
Use Scenario: Retaining user-defined therapy parameters and device calibration constants in Class II medical infusion pumps. IC Role / Device Role / Timing Role: Secure, tamper-resistant configuration store with software data protection enabled to meet IEC 62304 safety requirements. Use Value: 300 µA standby current extends battery life in portable devices; 5V-only operation avoids extra voltage translation circuitry. | Use Scenario: Storing MAC addresses, port mappings, and QoS profiles in managed Ethernet switches operating in telecom central offices. IC Role / Device Role / Timing Role: High-reliability firmware and parameter memory interfaced directly to ARM-based network processors via 8-bit parallel bus. Use Value: Pin-compatibility with AT29C010A allows reuse of legacy PCB footprints during product refresh cycles. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar Flash memory applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| AT29C256-90JI | 128 Kbit (16K × 8) density; identical 90 ns access, PLCC-32 package, and command set. | Limited to smaller firmware images; not suitable where >128 Kbit storage is required. | Select when application firmware fits within 128 Kbit and cost optimization is prioritized. |
| SST39VF200A-90-4C-NHE | 2 Mbit (256K × 8) density; 90 ns access; 3.3V core with 5V I/O tolerance; different command protocol (SST-style). | Requires voltage translation or level-shifting in pure 5V systems; incompatible software unlock sequence. | Choose only if migrating to 3.3V systems or needing higher density; not a drop-in replacement. |
Compared with AT29C256-90JI, the AT29C257-90JI doubles memory capacity while retaining identical timing, packaging, and command compatibility - making it the direct upgrade path. Against SST39VF200A-90-4C-NHE, AT29C257-90JI offers true 5V-only operation and proven legacy system compatibility but lacks density scalability.
Availability
AT29C257-90JI is available at Aetrix Electronics and suitable for industrial PLCs, automotive ECUs, medical infusion pumps, and networking switches requiring stable component supply across extended temperature ranges and long production lifecycles.
Supply support for AT29C257-90JI 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 global semiconductor company specializing in microcontrollers, analog components, and nonvolatile memory solutions for industrial, automotive, and consumer applications.
The AT29C257-90JI belongs to Microchip's legacy parallel Flash memory product line, designed specifically for in-system reprogrammability in 5V embedded systems requiring pin-compatible upgrades from EPROM or earlier Flash devices.
FAQ
What is the maximum operating temperature range for the AT29C257-90JI?
The AT29C257-90JI is rated for industrial temperature operation from -40°C to +85°C. This specification is verified per the manufacturer's ordering information table and applies to all DC and AC parametric limits under 5V ±10% supply conditions. The device maintains full functionality-including 90 ns read access and 10 ms page programming-across this full range, making it suitable for deployment in harsh environments such as factory floors or vehicle engine compartments.
Does the AT29C257-90JI require a high-voltage programming supply?
No, the AT29C257-90JI operates with 5V-only reprogramming - no external 12V or higher voltage is needed. All program and erase functions are initiated using standard 5V logic-level commands, including the 6-byte software chip erase and 3-byte software data protection enable/disable sequences. This eliminates the need for charge pumps or high-voltage generators in the host system, reducing design complexity and board space.
How does the AT29C257-90JI indicate completion of a page programming cycle?
The AT29C257-90JI provides two hardware-supported methods: DATA polling on I/O7 (complement of last loaded byte indicates active programming; true data indicates completion) and toggle-bit detection on I/O6 (toggling between 0 and 1 during programming; stable value indicates completion). Both methods are accessible at any time during the 10 ms internal write cycle and require no additional timing assumptions or fixed delays.
Is the AT29C257-90JI pin-compatible with other Atmel Flash devices?
Yes, the AT29C257-90JI is explicitly pin-compatible with AT29C010A and AT29C512 in the same PLCC-32 package. This allows direct PCB footprint reuse for system upgrades - for example, replacing a 1 Mbit AT29C010A with the 256 Kbit AT29C257-90JI requires no layout changes, though address decoding may need adjustment due to differing memory depth.
What is the endurance rating of the AT29C257-90JI, and how is it measured?
The AT29C257-90JI has a typical endurance of >10,000 write/erase cycles per memory sector. This rating is specified in the device description and confirmed in the Features section. Endurance is measured per sector (not per byte or per device), meaning any individual 64-byte page can sustain at least 10,000 full erase-and-program cycles while maintaining data retention and parametric compliance under industrial temperature conditions.
AT29C257-90JI 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:
- 90 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)
AT29C257-90JI FAQ
1.How can I place an order for AT29C257-90JI through Aetrix?
Please submit a Request for Quotation (RFQ) for AT29C257-90JI 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 AT29C257-90JI reliable?
The price and inventory of AT29C257-90JI are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for AT29C257-90JI is usually 5 days.
3.What payment methods are accepted for AT29C257-90JI?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for AT29C257-90JI transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for AT29C257-90JI?
AT29C257-90JI orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your AT29C257-90JI 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 AT29C257-90JI?
For technical support, including AT29C257-90JI datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your AT29C257-90JI requirements.
6.How does Aetrix verify that AT29C257-90JI is sourced from the original manufacturer or authorized distributors?
All AT29C257-90JI 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 AT29C257-90JI meets industry standards.
7.What is the process for return or replacement of AT29C257-90JI?
All AT29C257-90JI units undergo pre-shipment inspection (PSI). If there is an issue with AT29C257-90JI, 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 AT29C257-90JI part is unused and in its original packaging.
Return procedure for AT29C257-90JI:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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