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Microchip Technology AT28C64X-20JC
- Part No.:
- AT28C64X-20JC
- Manufacturer:
- Microchip Technology
- Category:
- Memory
- Package:
- 32-LCC (J-Lead)
- Datasheet:
-
AT28C64X-20JC.pdf
- Description:
- IC EEPROM 64KBIT PARALLEL 32PLCC
- Quantity:
- Payment:
- Shipping:
Inventory:4,811
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Product details
Overview
AT28C64X-20JC from Atmel is a 64 Kbit (8K × 8) parallel EEPROM with JEDEC-standard byte-wide pinout, 200 ns read access time, 1 ms or 200 µs byte write capability, and CMOS/TTL-compatible I/O-designed for nonvolatile storage in microprocessor-based systems requiring field-upgradable firmware or configuration data.
For engineers reviewing the AT28C64X-20JC datasheet, AT28C64X-20JC pinout, AT28C64X-20JC application, or AT28C64X-20JC equivalent, key selection criteria include its self-timed write cycle, RDY/BUSY signaling (not implemented on X-version), DATA polling support, 5V ±10% operation, and industrial temperature range (-40°C to +85°C) in PLCC-32 package.
Technical Context
The AT28C64X-20JC operates as a drop-in parallel memory replacement for SRAM in read cycles and supports direct microprocessor control via CE/OE/WE handshaking. Its internal address and data latches free the bus during self-timed byte writes, and it implements VCC-sense write protection and automatic clear-before-write logic.
Unlike standard ROMs, it enables in-system reprogramming without UV erasure or external high-voltage programming supplies. The device uses Atmel's nonvolatile technology with error correction for extended endurance (10⁴ or 10⁵ cycles) and 10-year data retention, plus 32 bytes of user-accessible identification memory at addresses 1FE0H–1FFFH.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Memory Size | 64 Kbit (8,192 × 8 bits) - provides sufficient space for boot code, calibration tables, or device configuration in embedded controllers. |
| Read Access Time | 200 ns - ensures compatibility with 5 MHz bus timing in legacy microprocessor systems without wait-state insertion. |
| Byte Write Time | 1 ms (standard) or 200 µs (E-version) - enables rapid field updates; AT28C64X-20JC uses standard 1 ms timing per byte. |
| Supply Voltage | 5V ±10% - simplifies power design by eliminating need for dedicated programming voltage rails. |
| Operating Temperature | -40°C to +85°C - qualified for industrial environments including factory automation and motor control systems. |
| Standby Current | 100 µA (CMOS) - reduces system-level power consumption during idle periods in battery-backed or energy-sensitive applications. |
| Endurance | 10,000 write/erase cycles - supports moderate-frequency configuration updates over product lifetime. |
Pinout & Package
AT28C64X-20JC is housed in a 32-lead Plastic J-leaded Chip Carrier (PLCC) package per JEDEC MS-016 AE, with pin 1 identified by index mark and pins 1 and 17 designated "Don't Connect" (DC). The package is lead-free compatible and RoHS-compliant.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| A0–A12 | Address Inputs | 13-bit address bus supporting full 8K-word addressing; A12 is MSB for 64 Kbit capacity. |
| I/O0–I/O7 | Bidirectional Data Bus | 8-bit parallel interface compatible with 8-bit microprocessors and bus architectures. |
| CE | Chip Enable | Active-low chip select; when high, places outputs in high-impedance state to prevent bus contention. |
| OE | Output Enable | Active-low output control; used with CE to gate read data onto bus without affecting write operations. |
| WE | Write Enable | Active-low write strobe; initiates self-timed byte write cycle on falling edge with data latched on rising edge. |
| RDY/BUSY | Open-Drain Status Output | Not connected (NC) on AT28C64X variant - write completion must be detected via DATA polling only. |
| VCC | Power Supply | +5V ±10% supply input; includes internal VCC-sense circuitry to inhibit writes below ~3.8V. |
| GND | Ground Reference | Signal and power ground reference for all inputs, outputs, and internal logic. |
Key Features
| Feature | Design Value |
|---|---|
| Self-timed byte write cycle | Eliminates need for external timing control logic; internal timer manages erase-and-program sequence automatically. |
| DATA polling (I/O7 complement) | Enables software-driven write completion detection without hardware status lines-critical for AT28C64X where RDY/BUSY is NC. |
| VCC sense and power-on delay | Prevents inadvertent writes during power ramp-up by inhibiting WE until VCC exceeds 3.8V and stabilizes for ≥5 ms. |
| JEDEC-standard byte-wide pinout | Ensures mechanical and electrical compatibility with existing PCB layouts designed for industry-standard parallel EEPROMs. |
| User-accessible ID memory (32 bytes) | Allows storage of unique device identifiers, calibration offsets, or manufacturing traceability data at fixed addresses 1FE0H–1FFFH. |
Applications
| Industrial PLC Configuration Storage | Legacy Embedded System Firmware Backup |
|---|---|
Use Scenario: Storing runtime-configurable I/O mapping, PID tuning parameters, and alarm thresholds in programmable logic controllers. IC Role / Device Role / Timing Role: Nonvolatile configuration memory accessed via 8-bit parallel bus during system initialization and parameter updates. Use Value: Enables field reconfiguration without firmware reflashing; 10,000-cycle endurance supports decades of maintenance cycles in fixed-installation equipment. |
Use Scenario: Retaining bootloader code and critical startup routines in aging 8051- or Z80-based instrumentation where flash memory is unavailable. IC Role / Device Role / Timing Role: Drop-in SRAM replacement with identical read timing (200 ns) and pinout, providing persistent storage across power cycles. Use Value: Eliminates need for battery-backed SRAM while maintaining full compatibility with legacy address/data bus timing and control signals. |
| Motor Drive Parameter Calibration | Point-of-Sale Terminal Settings Retention |
Use Scenario: Saving motor-specific commutation angles, current limits, and thermal derating curves in variable-frequency drives. IC Role / Device Role / Timing Role: Electrically erasable nonvolatile memory interfaced directly to drive MCU's parallel bus for real-time parameter access. Use Value: Supports factory and field calibration without soldering changes; 5V operation integrates seamlessly with drive's main logic supply rail. |
Use Scenario: Preserving tax rates, receipt formatting rules, and user preferences in retail terminals subject to frequent regulatory updates. IC Role / Device Role / Timing Role: Configuration EEPROM accessed during boot and updated via host processor during setup mode. Use Value: Guarantees settings survive AC power loss and cold resets; low 100 µA standby current extends backup battery life in UPS-equipped units. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar parallel EEPROM applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| AT28C64B-20JC | Same 64 Kbit capacity, 200 ns speed, and PLCC-32 package; improved reliability specs (10⁵ cycles, 100-year retention), but RDY/BUSY pin functional (not NC). | Supports hardware-ready signaling; requires minor board-level change if RDY/BUSY line is unused or tied high. | Select when enhanced endurance or hardware status feedback is required; not pin-identical due to active RDY/BUSY functionality. |
| MX28LV640BTC-20G | 64 Kbit parallel EEPROM in TSOP-28; 200 ns access, 5V operation, but no DATA polling-relies on RDY/BUSY only; different pinout and package. | Requires PCB redesign for TSOP footprint and signal routing; lacks PLCC mechanical robustness for vibration-prone environments. | Choose for space-constrained designs where TSOP is preferred; verify RDY/BUSY integration and absence of DATA polling in host firmware. |
Compared with AT28C64X-20JC, AT28C64B-20JC offers higher endurance and active RDY/BUSY, while MX28LV640BTC-20G trades PLCC ruggedness for smaller footprint but removes DATA polling fallback-making AT28C64X-20JC uniquely suited for legacy systems relying solely on polling-based write verification.
Availability
AT28C64X-20JC is available at Aetrix Electronics and suitable for industrial automation, legacy embedded systems, and motor control applications requiring stable component supply, long-term lifecycle support, and guaranteed availability of PLCC-packaged parallel EEPROMs.
Supply support for AT28C64X-20JC 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 AT28C64X series belongs to Atmel's parallel EEPROM product line, engineered for reliable, in-system reprogrammable nonvolatile storage in resource-constrained 8-bit microprocessor systems.
FAQ
What is the maximum operating temperature range for AT28C64X-20JC?
The AT28C64X-20JC is rated for industrial temperature operation from -40°C to +85°C. This specification is confirmed in the DC and AC Operating Range table on page 4 of the datasheet and applies specifically to all "JI", "PI", "SI", and "TI" suffix variants-including AT28C64X-20JC, which uses the "JC" (PLCC, commercial/industrial) package designation with industrial qualification.
Does AT28C64X-20JC support hardware READY/BUSY signaling?
No, AT28C64X-20JC does not support hardware READY/BUSY signaling. Per the Device Operation section on page 3, "The RDY/BUSY pin is not connected for the AT28C64X." Pin 1 is designated NC (No Connect) in all AT28C64X variants, including AT28C64X-20JC. Write completion must be detected exclusively via DATA polling of I/O7.
What is the typical byte write time for AT28C64X-20JC?
The AT28C64X-20JC uses the standard byte write time of 1 ms, as indicated in the AC Write Characteristics table (page 6) and Ordering Information (page 9). The faster 200 µs write option is exclusive to the "E" version (e.g., AT28C64XE-20JC), which is not the case for AT28C64X-20JC.
Is AT28C64X-20JC compatible with 5V TTL and CMOS logic families?
Yes, AT28C64X-20JC features CMOS and TTL compatible inputs and outputs, as stated in the Features list on page 1. Its VIH (2.0 V min), VIL (0.8 V max), VOH (2.4 V min at -400 µA), and VOL (0.45 V max at 2.1 mA) meet both TTL and CMOS voltage thresholds, enabling direct interfacing with legacy 8051, Z80, and 68000-series microprocessors.
How is write protection implemented on AT28C64X-20JC?
AT28C64X-20JC implements three-tier write protection: (1) VCC sense - write inhibited if supply drops below ~3.8 V; (2) Power-on delay - automatic 5 ms lockout after VCC stabilization; and (3) Signal-level inhibition - write disabled unless CE is low, OE is high, and WE is pulsed low. These mechanisms are detailed in the WRITE PROTECTION section on page 3 of the datasheet.
AT28C64X-20JC 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:
- 0°C ~ 70°C (TC)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 32-PLCC (13.97x11.43)
AT28C64X-20JC FAQ
1.How can I place an order for AT28C64X-20JC through Aetrix?
Please submit a Request for Quotation (RFQ) for AT28C64X-20JC 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-20JC reliable?
The price and inventory of AT28C64X-20JC are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for AT28C64X-20JC is usually 5 days.
3.What payment methods are accepted for AT28C64X-20JC?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for AT28C64X-20JC transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for AT28C64X-20JC?
AT28C64X-20JC orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your AT28C64X-20JC 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-20JC?
For technical support, including AT28C64X-20JC datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your AT28C64X-20JC requirements.
6.How does Aetrix verify that AT28C64X-20JC is sourced from the original manufacturer or authorized distributors?
All AT28C64X-20JC 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-20JC meets industry standards.
7.What is the process for return or replacement of AT28C64X-20JC?
All AT28C64X-20JC units undergo pre-shipment inspection (PSI). If there is an issue with AT28C64X-20JC, 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-20JC part is unused and in its original packaging.
Return procedure for AT28C64X-20JC:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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