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Microchip Technology AT28C64-25JI
- Part No.:
- AT28C64-25JI
- Manufacturer:
- Microchip Technology
- Category:
- Memory
- Package:
- 32-LCC (J-Lead)
- Datasheet:
-
AT28C64-25JI.pdf
- Description:
- IC EEPROM 64KBIT PARALLEL 32PLCC
- Quantity:
- Payment:
- Shipping:
Inventory:3,354
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Product details
Overview
AT28C64-25JI from Atmel is an industrial-grade, 64 Kbit (8K × 8) parallel EEPROM with 250 ns read access time, self-timed byte write (1 ms), and CMOS/TTL-compatible I/O. It operates at 5V ±10%, supports READY/BUSY and DATA polling for write completion detection, and is used in firmware storage and configuration retention for microcontroller-based systems.
For engineers reviewing the AT28C64-25JI datasheet, AT28C64-25JI pinout, AT28C64-25JI application, or AT28C64-25JI equivalent, key selection criteria include industrial temperature range (-40°C to +85°C), JEDEC-standard 28-pin PLCC package, 10⁴ write endurance, 10-year data retention, and direct microprocessor interface without external timing components.
Technical Context
The AT28C64-25JI implements a parallel EEPROM architecture with internal address/data latching and an autonomous control timer for self-timed byte writes. It uses VCC sensing and power-on delay to prevent inadvertent writes and supports chip erase via 12 V on OE.
Its dual-line chip enable (CE) and output enable (OE) logic enables flexible bus contention management during read cycles, while RDY/BUSY (open-drain) and DATA polling (I/O7 complement) provide deterministic write cycle termination detection - both fully functional in the -25JI variant per datasheet Rev. 0001H.
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 embedded controllers. |
| Read Access Time | 250 ns max; compatible with 4 MHz Z80, 8051, and 68K-family microprocessors without wait states. |
| Byte Write Time | 1 ms typical; self-timed with no external strobe required - simplifies firmware update routines. |
| Endurance | 10,000 write/erase cycles; validated for field-updatable parameter storage in industrial control modules. |
| Data Retention | 10 years at +85°C; ensures long-term reliability in unattended equipment like remote sensors and PLCs. |
| Supply Voltage | 5 V ±10%; operates directly from standard logic rails without regulation overhead. |
| Operating Temperature | -40°C to +85°C; qualified for industrial environments including factory automation and motor drives. |
Pinout & Package
AT28C64-25JI is supplied in a 32-lead Plastic J-Leaded Chip Carrier (PLCC) package per JEDEC MS-016AE, with pins 1 and 17 designated as "Don't Connect" (DC). Pin 1 is RDY/BUSY (open-drain) and functional in this variant.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| A0–A12 | Address Inputs | 13-bit address bus for full 8K-word addressing; TTL/CMOS compatible. |
| I/O0–I/O7 | Bidirectional Data Bus | 8-bit parallel interface; high-impedance when CE or OE is high. |
| CE | Chip Enable | Active-low chip select; enables memory access only when low and OE is low (read) or WE is low (write). |
| OE | Output Enable | Active-low output control; allows shared bus operation by disabling outputs independently of CE. |
| WE | Write Enable | Active-low write strobe; initiates self-timed byte write on falling edge with data latched on rising edge. |
| RDY/BUSY | Status Output | Open-drain signal pulled low during write; released upon completion - supports wired-OR multi-device monitoring. |
| VCC, GND | Power Supply | 5 V supply and ground; decoupling required within 1 cm due to fast switching transients. |
Key Features
| Feature | Design Value |
|---|---|
| Self-timed byte write | Eliminates need for external write pulse generators or timing logic - reduces BOM count and PCB area. |
| READY/BUSY + DATA polling | Dual independent write completion detection methods ensure robust firmware update handling across diverse host architectures. |
| VCC sense & power-on delay | Hardware-level write protection prevents corruption during brown-out or power ramp-up - no software intervention required. |
| JEDEC-standard pinout | Enables drop-in replacement of legacy 2764/27128 EPROMs and other 28-pin parallel EEPROMs in existing layouts. |
| 32-byte ID space | User-accessible memory region (1FE0H–1FFFH) for serialization, calibration data, or revision tracking without consuming main array. |
Applications
| Industrial PLC Configuration Storage | Medical Device Calibration Memory |
|---|---|
Use Scenario: Storing sensor calibration coefficients and operational thresholds in programmable logic controllers deployed in harsh factory environments. IC Role / Device Role / Timing Role: Nonvolatile configuration register providing persistent settings across power cycles and firmware updates. Use Value: Ensures deterministic startup behavior and eliminates manual recalibration after maintenance - supported by 10-year retention and -40°C to +85°C operation. |
Use Scenario: Retaining patient-specific therapy parameters and device serial traceability in portable infusion pumps and diagnostic monitors. IC Role / Device Role / Timing Role: Secure, tamper-resistant parameter vault accessed only during initialization or service mode. Use Value: Meets IEC 62304 Class C software requirements via guaranteed 10⁴ write cycles and hardware write inhibit during voltage instability. |
| Telecom Base Station Bootloader Storage | Automotive Body Control Module Settings |
Use Scenario: Holding bootloader images and FPGA configuration bitstreams in outdoor telecom cabinets subject to wide thermal cycling. IC Role / Device Role / Timing Role: Parallel-boot ROM replacement enabling fast, deterministic system initialization without serial interface latency. Use Value: 250 ns read access ensures sub-10 µs instruction fetch latency - critical for real-time boot sequence timing budgets. |
Use Scenario: Saving user preferences (window position, mirror angle, lighting profiles) and fault logs in automotive body control units. IC Role / Device Role / Timing Role: Low-power nonvolatile scratchpad accessible during vehicle wake-up events. Use Value: 100 µA standby current minimizes battery drain during extended parking; 5 V compatibility aligns with legacy automotive power domains. |
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 | Revised version with enhanced ESD tolerance (4 kV HBM) and tighter tACC characterization; same pinout, timing, and endurance. | Preferred for new designs requiring improved manufacturing yield and field reliability in electrostatic-prone assembly environments. | Select AT28C64B-25JI if board layout allows requalification; identical footprint and firmware compatibility. |
| MX28LV640C-25J1I | Macronix 64 Kbit parallel EEPROM with 250 ns access, but requires external VPP (12 V) for write and lacks RDY/BUSY pin. | Suitable where existing designs already use VPP generation circuitry and polling-only detection is acceptable. | Choose MX28LV640C-25J1I only if VPP infrastructure exists; not a drop-in replacement due to missing RDY/BUSY and different write enable protocol. |
Compared with AT28C64-25JI, the AT28C64B-25JI offers higher ESD robustness without design changes, while MX28LV640C-25J1I demands VPP support and sacrifices hardware-ready signaling - making AT28C64-25JI optimal for cost-sensitive, VPP-free industrial control designs.
Availability
AT28C64-25JI is available at Aetrix Electronics and suitable for industrial PLCs, medical diagnostics equipment, telecom base stations, automotive body control modules, and embedded instrumentation requiring stable component supply over extended product lifecycles.
Supply support for AT28C64-25JI 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 (now part of Microchip Technology) is a semiconductor manufacturer specializing in microcontrollers, nonvolatile memory, and secure authentication ICs.
The AT28C64 series was designed as a pin-compatible, low-power upgrade path from UV-erasable EPROMs, targeting firmware and configuration storage in microprocessor-based industrial and communications systems.
FAQ
What is the maximum operating temperature range for AT28C64-25JI?
The AT28C64-25JI is rated for industrial temperature operation from -40°C to +85°C. This specification is validated per the datasheet's DC and AC operating range table and applies across all electrical parameters including read access time, write endurance, and standby current. The -25JI suffix explicitly denotes the industrial grade variant of the AT28C64-25 family.
Does AT28C64-25JI require an external 12 V supply for normal operation?
No, AT28C64-25JI operates solely from a 5 V ±10% supply under normal read and write conditions. A 12 V supply is required only for two special functions: chip erase (applied to OE) and device identification memory access (applied to A9). These are infrequent operations and do not affect routine firmware or configuration storage use of AT28C64-25JI.
How does write protection work on AT28C64-25JI?
AT28C64-25JI implements three hardware-based write protection mechanisms: (1) VCC sense - write is inhibited if VCC drops below ~3.8 V; (2) power-on delay - automatic 5 ms lockout after VCC reaches threshold; and (3) signal-level inhibit - holding CE high, OE low, or WE high blocks all write cycles. These operate independently of firmware, ensuring robust protection against spurious writes.
Can AT28C64-25JI be used as a direct replacement for AT28C64-15JI in an existing design?
Yes, AT28C64-25JI is functionally and pin-compatible with AT28C64-15JI, differing only in maximum read access time (250 ns vs. 150 ns). All other electrical characteristics, pinout, timing waveforms, and feature set are identical. Systems designed for the -15JI will operate reliably with the -25JI, though worst-case read latency increases by 100 ns.
What is the purpose of the RDY/BUSY pin on AT28C64-25JI?
The RDY/BUSY pin (Pin 1) on AT28C64-25JI is an open-drain output that is actively pulled low during byte write or chip erase operations and released (high-impedance) upon completion. It enables hardware handshaking for precise write cycle synchronization and supports wired-OR connection of multiple devices to a single interrupt line - a key capability confirmed for the -25JI variant in the pin configuration diagrams and device operation section.
AT28C64-25JI 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)
AT28C64-25JI FAQ
1.How can I place an order for AT28C64-25JI through Aetrix?
Please submit a Request for Quotation (RFQ) for AT28C64-25JI 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 AT28C64-25JI reliable?
The price and inventory of AT28C64-25JI are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for AT28C64-25JI is usually 5 days.
3.What payment methods are accepted for AT28C64-25JI?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for AT28C64-25JI transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for AT28C64-25JI?
AT28C64-25JI orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your AT28C64-25JI 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 AT28C64-25JI?
For technical support, including AT28C64-25JI datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your AT28C64-25JI requirements.
6.How does Aetrix verify that AT28C64-25JI is sourced from the original manufacturer or authorized distributors?
All AT28C64-25JI 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 AT28C64-25JI meets industry standards.
7.What is the process for return or replacement of AT28C64-25JI?
All AT28C64-25JI units undergo pre-shipment inspection (PSI). If there is an issue with AT28C64-25JI, 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 AT28C64-25JI part is unused and in its original packaging.
Return procedure for AT28C64-25JI:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
AT28C64-25JI Tags
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