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Microchip Technology AT28C64-20JI
- Part No.:
- AT28C64-20JI
- Manufacturer:
- Microchip Technology
- Category:
- Memory
- Package:
- 32-LCC (J-Lead)
- Datasheet:
-
AT28C64-20JI.pdf
- Description:
- IC EEPROM 64KBIT PARALLEL 32PLCC
- Quantity:
- Payment:
- Shipping:
Inventory:4,566
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Product details
Overview
AT28C64-20JI from Atmel is an 8K × 8-bit parallel EEPROM with 200 ns read access time, 1 ms byte write cycle, CMOS/TTL-compatible I/O, JEDEC-standard pinout, and industrial temperature range (−40°C to +85°C), used for nonvolatile configuration storage in microcontroller-based systems.
For engineers reviewing the AT28C64-20JI datasheet, AT28C64-20JI pinout, AT28C64-20JI application, or AT28C64-20JI equivalent, key selection considerations include its self-timed write operation, RDY/BUSY and DATA polling status detection, VCC-sense write protection, chip clear capability, and PLCC-32 packaging for high-reliability embedded firmware storage.
Technical Context
The AT28C64-20JI operates as a byte-addressable parallel EEPROM accessed like SRAM-requiring no external timing components during read or write cycles. Its internal address and data latches free the bus after initiation, while the self-timed write cycle includes automatic erase-before-write and internal control timer execution.
Two hardware-level write completion detection methods are supported: open-drain RDY/BUSY output (active-low during write) and DATA polling of I/O7 (complement-to-data during write, true data on completion). Write inhibition is enforced via VCC sense (<3.8 V), 5 ms power-on delay, and logic-level gating (OE high, CE high, or WE high).
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Memory Size | 8,192 words × 8 bits (64 Kbit); supports full memory array addressing with A0–A12. |
| Read Access Time | 200 ns max; enables direct interface with 5 MHz microprocessors without wait states. |
| Byte Write Cycle | 1 ms typical; self-timed-no external strobe or timing circuit required. |
| Supply Voltage | 5 V ± 10%; compatible with standard TTL/CMOS logic rails and legacy 5 V systems. |
| Operating Temperature | −40°C to +85°C; qualified for industrial-grade embedded control and instrumentation. |
| Standby Current | 100 µA max (CMOS); enables low-power retention in battery-backed or energy-constrained designs. |
| Endurance | 10,000 write/erase cycles; sufficient for infrequent configuration updates over product lifetime. |
| Data Retention | 10 years at +85°C; ensures long-term reliability in thermally stressed environments. |
Pinout & Package
AT28C64-20JI is packaged in a 32-lead Plastic J-Leaded Chip Carrier (PLCC-32), compliant with JEDEC MS-016AE. 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 supporting full 8K-word decoding; TTL/CMOS compatible. |
| I/O0–I/O7 | Bidirectional Data Bus | 8-bit parallel data path; high-impedance when disabled (CE or OE high). |
| CE | Chip Enable | Active-low chip select; enables device for read/write when low and OE/WE appropriately asserted. |
| OE | Output Enable | Active-low output gate; controls data bus drive during read; must be high during write. |
| WE | Write Enable | Active-low write strobe; initiates self-timed byte write on falling edge. |
| RDY/BUSY | Status Output | Open-drain active-low signal indicating write in progress; supports wired-OR multi-device monitoring. |
| VCC | Power Supply | +5 V ± 10% supply input; powers core logic and memory array. |
| GND | Ground | Reference return for all signals and power; requires low-impedance PCB connection. |
Key Features
| Feature | Design Value |
|---|---|
| Self-timed Byte Write | Eliminates need for external write timing control-internal timer manages erase-and-program sequence automatically. |
| RDY/BUSY Status Output | Open-drain signal allows multiple AT28C64-20JI devices to share one status line for system-level write coordination. |
| DATA Polling Support | I/O7 toggles complement-to-data during write, enabling software-driven status check without dedicated hardware lines. |
| VCC-Sense Write Protection | Prevents accidental writes during power ramp-up or brownout by disabling write function below ~3.8 V. |
| Chip Clear Function | Entire memory set to FFh via 12 V on OE and 10 ms WE pulse-enables factory reset or field reinitialization. |
| Device Identification Area | 32 bytes at 1FE0H–1FFFH accessible with A9 = 12 V; usable for serialization, calibration data, or firmware version tagging. |
Applications
| Industrial PLC Configuration Storage | Medical Device Calibration Data |
|---|---|
Use Scenario: Storing I/O mapping, scaling coefficients, and alarm thresholds in programmable logic controllers deployed in factory automation. IC Role / Device Role / Timing Role: Nonvolatile configuration register providing persistent parameter storage between power cycles. Use Value: Ensures deterministic startup behavior and eliminates manual reconfiguration after maintenance or power loss. | Use Scenario: Retaining sensor calibration offsets, patient-specific therapy settings, and regulatory audit logs in portable diagnostic equipment. IC Role / Device Role / Timing Role: Secure, long-retention data vault for safety-critical operational parameters. Use Value: Meets IEC 62304 requirements for data integrity and traceability across device lifecycle. |
| Avionics Control Module Bootloader Settings | Test Equipment Firmware Patch Storage |
Use Scenario: Holding boot mode flags, communication protocol selection, and hardware revision identifiers in airborne flight control subsystems. IC Role / Device Role / Timing Role: Read-on-reset configuration hub interfacing directly with microcontroller address/data bus. Use Value: Enables field-upgradable behavior without modifying main flash image or requiring JTAG intervention. | Use Scenario: Storing hotfix patches, test script revisions, and calibration compensation tables in automated bench test systems. IC Role / Device Role / Timing Role: Field-serviceable update repository decoupled from primary firmware memory. Use Value: Reduces downtime during calibration drift correction or compliance updates without full firmware reflashing. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar parallel EEPROM applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| AT28C64B-20JI | Improved endurance (100K cycles) and faster write (200 µs); same pinout, voltage, and timing interface. | Preferred where frequent field updates or extended service life are required. | Select AT28C64B-20JI if write-cycle longevity exceeds 10K cycles or sub-millisecond writes are mandatory. |
| MX28LV640CT-20G | Same 8K×8 organization and 200 ns access, but uses 3.3 V core with 5 V tolerant I/O; different pinout (SOIC-28 vs PLCC-32). | Requires PCB redesign and level-shifting for 5 V-only systems; suited for mixed-voltage platforms. | Choose MX28LV640CT-20G only when migrating toward lower-power 3.3 V architectures with compatible layout support. |
Compared with AT28C64-20JI, the AT28C64B-20JI offers higher endurance and faster writes in identical packaging, while MX28LV640CT-20G provides 3.3 V operation at the cost of pinout incompatibility and board-level redesign-making AT28C64-20JI optimal for drop-in replacement in legacy 5 V industrial designs.
Availability
AT28C64-20JI is available at Aetrix Electronics and suitable for industrial PLCs, medical diagnostics, avionics control modules, and automated test equipment requiring stable component supply and long-term obsolescence management.
Supply support for AT28C64-20JI 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 product line delivers parallel-interface EEPROMs optimized for direct microprocessor integration in industrial, automotive, and communications systems requiring reliable, low-power, pin-compatible configuration storage.
FAQ
What is the maximum read access time specified for the AT28C64-20JI?
The AT28C64-20JI has a maximum read access time of 200 ns, measured from address valid to valid data on I/O0–I/O7 under industrial temperature conditions (−40°C to +85°C) and 5 V ±10% supply. This specification ensures compatibility with 5 MHz microprocessors without wait-state insertion and is verified per AC Read Characteristics table in the official Atmel datasheet Rev. 0001H.
Does the AT28C64-20JI support hardware write protection?
Yes, the AT28C64-20JI implements three hardware-level write protection mechanisms: (1) VCC sense disables writes below ~3.8 V, (2) a 5 ms internal power-on delay prevents writes during supply ramp-up, and (3) logical gating-holding OE high, CE high, or WE high inhibits all byte write operations. These features ensure robust immunity to spurious writes during power transitions or noise events in the AT28C64-20JI's target applications.
How does the RDY/BUSY pin function on the AT28C64-20JI?
The RDY/BUSY pin (Pin 1) on the AT28C64-20JI is an open-drain output that goes low during any self-timed byte write cycle and releases (pulls up via external resistor) upon completion. It supports wired-OR connection with other AT28C64-20JI devices on the same bus, enabling centralized write-status monitoring. The pin is not connected in AT28C64X variants, confirming its functional presence and purpose specifically in the AT28C64-20JI.
Can the AT28C64-20JI be used as a direct replacement for the AT28C64-15JI?
Yes-the AT28C64-20JI is pin-compatible and functionally identical to the AT28C64-15JI except for its slower 200 ns read access (vs. 150 ns), making it suitable as a drop-in replacement in systems where timing margins allow. Both share identical PLCC-32 packaging, industrial temperature rating, 1 ms write cycle, and feature set-including RDY/BUSY, DATA polling, and chip clear-ensuring seamless integration into existing AT28C64-15JI designs.
What package type is used for the AT28C64-20JI?
The AT28C64-20JI uses a 32-lead Plastic J-Leaded Chip Carrier (PLCC-32) package per JEDEC MS-016AE, with pin 1 index-marked and pins 1 and 17 designated "Don't Connect." This surface-mount package provides mechanical robustness and thermal performance suitable for industrial PCB assembly, and is explicitly listed in the Atmel ordering information table for the AT28C64-20JI variant.
AT28C64-20JI 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:
- 200 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)
AT28C64-20JI FAQ
1.How can I place an order for AT28C64-20JI through Aetrix?
Please submit a Request for Quotation (RFQ) for AT28C64-20JI 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 AT28C64-20JI reliable?
The price and inventory of AT28C64-20JI are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for AT28C64-20JI is usually 5 days.
3.What payment methods are accepted for AT28C64-20JI?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for AT28C64-20JI transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for AT28C64-20JI?
AT28C64-20JI orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your AT28C64-20JI 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 AT28C64-20JI?
For technical support, including AT28C64-20JI datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your AT28C64-20JI requirements.
6.How does Aetrix verify that AT28C64-20JI is sourced from the original manufacturer or authorized distributors?
All AT28C64-20JI 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 AT28C64-20JI meets industry standards.
7.What is the process for return or replacement of AT28C64-20JI?
All AT28C64-20JI units undergo pre-shipment inspection (PSI). If there is an issue with AT28C64-20JI, 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 AT28C64-20JI part is unused and in its original packaging.
Return procedure for AT28C64-20JI:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
AT28C64-20JI Tags
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AT24C02C-XHM-T
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AT21CS01-STUM10-T
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