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Microchip Technology AT28C64X-25JI
- Part No.:
- AT28C64X-25JI
- Manufacturer:
- Microchip Technology
- Category:
- Memory
- Package:
- 32-LCC (J-Lead)
- Datasheet:
-
AT28C64X-25JI.pdf
- Description:
- IC EEPROM 64KBIT PARALLEL 32PLCC
- Quantity:
- Payment:
- Shipping:
Inventory:3,756
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Product details
Overview
AT28C64X-25JI from Atmel is a 64K-bit (8K × 8) parallel EEPROM with 250 ns maximum read access time, self-timed byte write cycle, and industrial temperature range (–40°C to +85°C). It operates from a single 5V ±10% supply, supports CMOS/TTL-compatible interfacing, and features READY/BUSY signaling (disabled in X-version) and DATA polling for write completion detection. Used in firmware storage and configuration memory for embedded controllers.
For engineers reviewing the AT28C64X-25JI datasheet, AT28C64X-25JI pinout, AT28C64X-25JI application, or AT28C64X-25JI equivalent, this page delivers verified timing specs, JEDEC-compliant pin mapping, endurance and retention data, industrial-grade reliability metrics, and real-world use context for legacy system design and BOM continuity planning.
Technical Context
The AT28C64X-25JI implements a parallel EEPROM architecture with internal address/data latching and an autonomous control timer that manages erase-before-write sequencing without external timing components. Its dual-line chip enable (CE) and output enable (OE) logic enables flexible bus arbitration in microprocessor systems.
Unlike standard SRAM, it retains data without power and supports in-system byte-level reprogramming via standard microprocessor bus cycles - no high-voltage programming supply required except for optional CHIP CLEAR (12 V on OE) or device ID access (12 V on A9). The "X" suffix denotes RDY/BUSY pin disabled (NC), distinguishing it from non-X variants.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Memory Size | 64 Kbit (8,192 × 8 bits); sufficient for boot code, calibration tables, or device configuration in 8-bit microcontroller systems. |
| Read Access Time | 250 ns max; compatible with 4 MHz Z80, 8051, and 68000-based systems without wait-state insertion. |
| Byte Write Time | 1 ms typical (standard endurance mode); enables reliable field updates without external timing circuitry. |
| Endurance | 10,000 write/erase cycles; validated for long-term use in industrial logging and parameter storage applications. |
| Data Retention | 10 years at +85°C; meets extended-life requirements for unattended equipment and infrastructure controllers. |
| Supply Voltage | 5 V ±10%; eliminates need for dedicated programming voltage regulators in legacy 5V designs. |
| Operating Temperature | –40°C to +85°C; qualified for industrial automation, motor drives, and telecom line cards. |
Pinout & Package
AT28C64X-25JI is packaged in a 32-lead Plastic J-Leaded Chip Carrier (PLCC), JEDEC MS-016AE compliant, with 1.27 mm pitch and surface-mount compatibility. Pin 1 is index-marked; pins 1 and 17 are designated "Don't Connect" per datasheet.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| A0–A12 | Address Inputs | 13-bit address bus for full 8K-word addressing; TTL/CMOS compatible thresholds ensure robust decoding. |
| I/O0–I/O7 | Bidirectional Data Bus | 8-bit parallel interface; supports true read/write cycles without direction control lines. |
| CE | Chip Enable | Active-low chip select; enables device participation in shared memory bus; high-Z when inactive. |
| OE | Output Enable | Active-low output gate; used with CE to prevent bus contention during multi-device reads. |
| WE | Write Enable | Active-low write strobe; initiates self-timed byte write on falling edge; latches address/data internally. |
| RDY/BUSY | Open-Drain Status Output | Not connected (NC) in AT28C64X variant; requires DATA polling instead of hardware handshake. |
| VCC, GND | Power Supply | Single 5V supply; decoupling recommended within 1 cm due to 30 mA active current surge during writes. |
Key Features
| Feature | Design Value |
|---|---|
| Self-timed byte write | Eliminates external timing components; internal control timer handles erase-before-write and completion sequencing automatically. |
| DATA polling support | Enables software-driven write completion detection via I/O7 complement behavior - no RDY/BUSY pin required. |
| Write protection logic | VCC sense (inhibits write if <3.8 V), power-on delay (~5 ms), and triple-gate inhibit (OE high / CE low / WE high) prevent accidental writes. |
| JEDEC-standard pinout | Ensures drop-in compatibility with existing 28-pin and 32-pin parallel EEPROM footprints across multiple vendors. |
| Industrial temperature rating | Validated operation from –40°C to +85°C supports deployment in harsh environments without derating. |
Applications
| Industrial PLC Configuration Storage | Legacy Microcontroller Bootloader Memory |
|---|---|
Use Scenario: Storing user-defined I/O mapping, PID tuning parameters, and alarm thresholds in programmable logic controllers. IC Role / Device Role / Timing Role: Nonvolatile configuration memory accessed during startup and runtime via 8-bit parallel bus. Use Value: Enables field-upgradable settings without requiring firmware reflashing or battery-backed SRAM. |
Use Scenario: Holding bootloader code and secure boot vectors for 8051 or Z80-based embedded systems. IC Role / Device Role / Timing Role: Primary boot ROM with 250 ns read access supporting zero-wait-state execution. Use Value: Guarantees deterministic boot timing and eliminates dependency on external clock sources or complex initialization sequences. |
| Telecom Line Card Calibration Data | Medical Device Safety Parameter Storage |
Use Scenario: Retaining factory-calibrated ADC/DAC offsets and gain coefficients in T1/E1 interface modules. IC Role / Device Role / Timing Role: Read-only data repository during power-up; written once during manufacturing test. Use Value: Ensures measurement accuracy traceability over 10-year product lifecycle without recalibration. |
Use Scenario: Storing critical safety limits (e.g., max motor torque, temperature cutoffs) in Class II medical infusion pumps. IC Role / Device Role / Timing Role: Tamper-resistant configuration store with write-inhibit logic preventing runtime corruption. Use Value: Meets IEC 62304 requirement for immutable safety-critical parameters across power cycles and environmental stress. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar parallel EEPROM applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| AT28C64B-25JI | Same pinout, same speed grade, but includes RDY/BUSY pin (not NC); higher endurance option available (100K cycles). | Supports hardware-ready handshaking; preferred where bus arbitration must avoid polling overhead. | Select AT28C64B-25JI only if RDY/BUSY signal routing is feasible and faster write verification is needed. |
| MX28LV640E-25J1I | 32-pin PLCC, 5V operation, 250 ns access, but uses different write protocol (no DATA polling; relies on tWC timing). | Lacks built-in DATA polling; requires precise timing control instead of status-driven writes. | Choose MX28LV640E-25J1I only when migrating to Macronix's newer process and accepting tighter timing margins. |
Compared with AT28C64X-25JI, the AT28C64B-25JI adds hardware-ready capability at identical speed and package, while MX28LV640E-25J1I trades polling flexibility for marginally improved endurance - both require layout review and firmware adaptation for status-handling differences.
Availability
AT28C64X-25JI is available at Aetrix Electronics and suitable for industrial automation, legacy telecom infrastructure, and medical device manufacturing requiring stable component supply across extended product lifecycles.
Supply support for AT28C64X-25JI 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
Atmel Corporation was a leading designer of microcontrollers, nonvolatile memory, and analog semiconductors, acquired by Microchip Technology in 2016; its legacy EEPROM portfolio remains widely deployed in industrial systems.
The AT28C64X series was designed specifically for 5V parallel bus systems needing field-updatable, pin-compatible EEPROM replacement for EPROM or battery-backed SRAM - emphasizing reliability, ease of integration, and long-term availability.
FAQ
What is the RDY/BUSY pin configuration on AT28C64X-25JI?
The AT28C64X-25JI has the RDY/BUSY pin (Pin 1) designated as "No Connect" (NC), per Atmel's datasheet revision 0001H. This distinguishes it from non-X variants like AT28C64-25JI, which implement an open-drain ready/busy output. For write completion detection, AT28C64X-25JI relies exclusively on DATA polling of I/O7. No external pull-up is required on Pin 1 for AT28C64X-25JI.
Does AT28C64X-25JI support in-system programming without high voltage?
Yes, AT28C64X-25JI supports standard in-system byte programming using only the 5V supply - no external 12V programming voltage is needed for routine writes. High voltage (12 V ±0.5 V) is required only for two special operations: CHIP CLEAR (applied to OE) and accessing the 32-byte device identification area (applied to A9). These are infrequent, factory-controlled functions - not part of normal firmware update workflows for AT28C64X-25JI.
What is the endurance rating of AT28C64X-25JI, and how is it validated?
The AT28C64X-25JI is rated for 10,000 write/erase cycles, as specified in the Atmel datasheet section "High Reliability". This endurance level is validated under industrial temperature conditions (–40°C to +85°C) and reflects guaranteed minimum performance across the full operating voltage range (4.5 V to 5.5 V). It does not include the optional "E" variant (100K cycles); AT28C64X-25JI is the standard endurance version.
Can AT28C64X-25JI be used as a direct replacement for AT28C64-25JI?
No - AT28C64X-25JI is not a direct replacement for AT28C64-25JI due to the RDY/BUSY pin difference: Pin 1 is NC in AT28C64X-25JI but functional in AT28C64-25JI. Hardware changes are required to remove RDY/BUSY signal routing and adapt firmware to use DATA polling exclusively. Both share identical timing, pinout, and electrical specs otherwise, but the X-suffix indicates a deliberate functional divergence for polling-only systems.
What package type is used for AT28C64X-25JI, and what are its key mechanical features?
AT28C64X-25JI uses a 32-lead Plastic J-Leaded Chip Carrier (PLCC), JEDEC MS-016AE compliant. Key features include a 1.27 mm lead pitch, body size of 13.9 mm × 13.9 mm, and J-bend leads suitable for reflow soldering. Pins 1 and 17 are marked "Don't Connect" and must remain unconnected per datasheet - no bonding or PCB trace routing is permitted to those pins for AT28C64X-25JI.
AT28C64X-25JI 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:
- EEPROM
- Technology:
- EEPROM
- Memory Size:
- 64Kbit
- Memory Organization:
- 8K x 8
- Memory Interface:
- Parallel
- Clock Frequency:
- -
- Write Cycle Time - Word, Page:
- 1ms
- Access Time:
- 250 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)
AT28C64X-25JI FAQ
1.How can I place an order for AT28C64X-25JI through Aetrix?
Please submit a Request for Quotation (RFQ) for AT28C64X-25JI 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 AT28C64X-25JI reliable?
The price and inventory of AT28C64X-25JI are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for AT28C64X-25JI is usually 5 days.
3.What payment methods are accepted for AT28C64X-25JI?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for AT28C64X-25JI transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for AT28C64X-25JI?
AT28C64X-25JI orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your AT28C64X-25JI 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 AT28C64X-25JI?
For technical support, including AT28C64X-25JI datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your AT28C64X-25JI requirements.
6.How does Aetrix verify that AT28C64X-25JI is sourced from the original manufacturer or authorized distributors?
All AT28C64X-25JI 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 AT28C64X-25JI meets industry standards.
7.What is the process for return or replacement of AT28C64X-25JI?
All AT28C64X-25JI units undergo pre-shipment inspection (PSI). If there is an issue with AT28C64X-25JI, 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 AT28C64X-25JI part is unused and in its original packaging.
Return procedure for AT28C64X-25JI:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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