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Microchip Technology AT29C257-90JC
- Part No.:
- AT29C257-90JC
- Manufacturer:
- Microchip Technology
- Category:
- Memory
- Package:
- 32-LCC (J-Lead)
- Datasheet:
-
AT29C257-90JC.pdf
- Description:
- IC FLASH 256KBIT PARALLEL 32PLCC
- Quantity:
- Payment:
- Shipping:
Inventory:4,482
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Product details
Overview
AT29C257-90JC from Microchip Technology (formerly Atmel) is a 5-V-only, 256 Kbit (32K × 8) in-system reprogrammable Flash PEROM with 90 ns read access time, 10 ms page program time, and CMOS standby current of 300 µA. It operates across 0°C to 70°C, uses PLCC-32 packaging, and supports hardware/software data protection for embedded firmware storage in microcontroller-based systems.
For engineers reviewing the AT29C257-90JC datasheet, AT29C257-90JC pinout, AT29C257-90JC application, or AT29C257-90JC equivalent, key selection criteria include 5V-only programming compatibility, 64-byte page load timing, DATA polling/Toggle Bit end-of-write detection, and PLCC-32 footprint alignment with legacy AT29C010A/AT29C512 designs.
Technical Context
The AT29C257-90JC implements a nonvolatile Flash architecture with internal latching for 64-byte page loads and autonomous erase-program sequencing controlled by an on-chip timer. Its dual-line chip enable (CE) and output enable (OE) logic 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 pulse with OE high), and software-controlled programming/erasure using 3- or 6-byte command sequences at fixed addresses (e.g., 5555H/2AAAH). Hardware protection includes VCC sense (<3.8 V inhibition), 5 ms power-on delay, and noise filtering on WE/CE inputs.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Memory Size | 256 Kbit (32,768 × 8), directly replaceable for 32K-word code/data storage in 8-bit microcontroller systems |
| Read Access Time | 90 ns max - determines minimum bus cycle time for CPU interface without wait states |
| Page Program Time | 10 ms typical - defines firmware update latency per 64-byte block in field-upgrade scenarios |
| VCC Supply | 5 V ± 10% - eliminates need for dedicated programming voltage rails in system design |
| Standby Current | 300 µA CMOS - enables low-power retention during sleep modes in battery-backed applications |
| Endurance | >10,000 write/erase cycles per sector - supports long-term field firmware revision management |
| Operating Temp | 0°C to +70°C - qualified for commercial-grade industrial control and instrumentation environments |
Pinout & Package
AT29C257-90JC 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 PCB upgrades.
| 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 device selection; must be low for read, program, or erase; enables bus sharing |
| OE | Output Enable | Active-low output control; high-Z when high, prevents bus contention during writes |
| WE | Write Enable | Active-low signal initiating byte load or program cycle; used with CE for timing-critical page loading |
| I/O0–I/O7 | Bidirectional Data Bus | 8-bit parallel interface; carries address latches during load, data during read/write, and Toggle Bit/DATA Polling status |
| 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 12 V programming supply, simplifying power architecture and reducing BOM count |
| DATA Polling & Toggle Bit | Enables real-time, non-interrupting end-of-program detection via I/O7 complement or I/O6 toggling |
| Software Data Protection | User-configurable 3-byte unlock sequence prevents accidental writes during power transitions or noise events |
| Hardware Data Protection | VCC sense, 5 ms power-on delay, and 15 ns noise filter on WE/CE prevent spurious programming |
| Page-based programming | 64-byte internal latching allows background bus release during 10 ms internal erase-program cycle |
Applications
| Industrial PLC Firmware Storage | Medical Device Bootloader Memory |
|---|---|
|
Use Scenario: Storing firmware images and configuration parameters in programmable logic controllers requiring field updates without hardware intervention. IC Role / Device Role / Timing Role: Nonvolatile code storage with in-system reprogrammability; 90 ns read speed ensures deterministic instruction fetch timing for real-time control loops. Use Value: Enables secure, 5V-only firmware patching via serial interface with hardware/software write protection preventing corruption during brown-out events. |
Use Scenario: Holding certified bootloader and calibration data in Class II medical instruments where data integrity and regulatory traceability are mandatory. IC Role / Device Role / Timing Role: Trusted boot memory with >10,000 endurance cycles; CMOS standby current of 300 µA supports battery-backed retention during power loss. Use Value: Meets IEC 62304 requirements for safe firmware update mechanisms via validated software unlock sequences and Toggle Bit verification. |
| Automotive Diagnostic Module Code | Legacy Industrial HMI Configuration |
|
Use Scenario: Storing diagnostic protocol stacks (e.g., UDS, KWP2000) in OBD-II modules operating across extended temperature ranges. IC Role / Device Role / Timing Role: Read-optimized Flash memory with 0°C to +70°C rating; pin-compatible upgrade path from AT29C512 for EOL mitigation. Use Value: Supports rapid 10 ms page writes during dealer-level software reflashing while maintaining immunity to automotive electrical noise via hardware protection. |
Use Scenario: Retaining user-defined screen layouts and I/O mapping in aging human-machine interface terminals with no redesign budget. IC Role / Device Role / Timing Role: Drop-in replacement for AT29C010A in PLCC-32 footprints; identical 32K × 8 organization and 5V operation. Use Value: Extends product lifecycle without PCB revision - leverages existing layout, test fixtures, and firmware drivers. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar Flash memory applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SST39VF200A-90-4C-NHE | 4 Mbit (256K × 16) organization; 90 ns access; 3.3 V supply; different command set and page size (128-byte) | Requires data bus width change (16-bit vs. 8-bit); not pin-compatible; needs firmware adaptation for command sequences | Select only if migrating to 3.3 V system and redesigning bus interface; not suitable for drop-in replacement |
| MX29LV256ETTI-90G | 256 Mbit (32M × 8); 90 ns access; 3.0–3.6 V supply; requires 12 V for reset; no software data protection | Higher density but incompatible voltage domain; lacks software lock/unlock; different erase granularity (64 KB sectors) | Use only for new 3.3 V designs needing larger capacity; not viable for AT29C257-90JC footprint or 5 V environment |
Compared with SST39VF200A-90-4C-NHE and MX29LV256ETTI-90G, the AT29C257-90JC uniquely delivers 5 V-only operation, PLCC-32 pin compatibility with legacy Atmel Flash, integrated software/hardware write protection, and deterministic 64-byte page programming - making it irreplaceable in cost-sensitive, field-upgradable 8-bit embedded systems.
Availability
AT29C257-90JC is available at Aetrix Electronics and suitable for industrial PLC firmware storage, medical device bootloader memory, and automotive diagnostic module code requiring stable component supply across commercial temperature range.
Supply support for AT29C257-90JC 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 products including the AT29C257 series.
The AT29C257-90JC belongs to Atmel's early-generation 5 V Flash PEROM family, designed specifically for in-system firmware storage in resource-constrained 8-bit microcontroller applications with strict voltage and footprint constraints.
FAQ
What is the maximum operating temperature range for the AT29C257-90JC?
The AT29C257-90JC is rated for commercial operation from 0°C to +70°C. Its PLCC-32 package and internal circuitry are characterized and tested across this range, ensuring reliable read access time ≤90 ns and program timing compliance. It is not qualified for industrial (-40°C to +85°C) operation - that specification applies to the AT29C257-90JI variant.
Does the AT29C257-90JC require external high-voltage circuitry for programming?
No, the AT29C257-90JC does not require external high-voltage circuitry. It supports 5-V-only reprogramming using standard logic-level signals. All program and erase operations are initiated via software command sequences applied to specific addresses (e.g., 5555H/2AAAH), eliminating the need for 12 V programming supplies or dedicated HV generators.
How is end-of-program detection implemented in the AT29C257-90JC?
The AT29C257-90JC provides two hardware-supported methods: DATA polling (monitoring complement of I/O7 during read) and Toggle Bit (observing I/O6 toggling state). Both operate without halting the host processor and are valid at any point during the 10 ms internal program cycle - enabling efficient, interrupt-driven firmware update routines in the AT29C257-90JC.
Is the AT29C257-90JC pin-compatible with other Atmel Flash devices?
Yes, the AT29C257-90JC is explicitly pin-compatible with AT29C010A and AT29C512 in the same PLCC-32 package. This allows direct PCB-level replacement for system upgrades, provided memory map alignment and timing margins accommodate the 90 ns access specification. No trace modifications or socket changes are needed.
What protection mechanisms prevent accidental writes to the AT29C257-90JC?
The AT29C257-90JC implements dual-layer protection: hardware features (VCC sense below 3.8 V, 5 ms power-on delay, noise filtering on WE/CE) and software features (user-enabled 3-byte unlock sequence). Once enabled, software protection remains active across power cycles until explicitly disabled - ensuring robust defense against spurious writes in noisy or unstable power environments.
AT29C257-90JC 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:
- 0°C ~ 70°C (TC)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 32-PLCC (13.97x11.43)
AT29C257-90JC FAQ
1.How can I place an order for AT29C257-90JC through Aetrix?
Please submit a Request for Quotation (RFQ) for AT29C257-90JC 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 AT29C257-90JC reliable?
The price and inventory of AT29C257-90JC are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for AT29C257-90JC is usually 5 days.
3.What payment methods are accepted for AT29C257-90JC?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for AT29C257-90JC transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for AT29C257-90JC?
AT29C257-90JC orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your AT29C257-90JC 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 AT29C257-90JC?
For technical support, including AT29C257-90JC datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your AT29C257-90JC requirements.
6.How does Aetrix verify that AT29C257-90JC is sourced from the original manufacturer or authorized distributors?
All AT29C257-90JC 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 AT29C257-90JC meets industry standards.
7.What is the process for return or replacement of AT29C257-90JC?
All AT29C257-90JC units undergo pre-shipment inspection (PSI). If there is an issue with AT29C257-90JC, 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 AT29C257-90JC part is unused and in its original packaging.
Return procedure for AT29C257-90JC:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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