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Microchip Technology AT28HC64B-12JI
- Part No.:
- AT28HC64B-12JI
- Manufacturer:
- Microchip Technology
- Category:
- Memory
- Package:
- 32-LCC (J-Lead)
- Datasheet:
-
AT28HC64B-12JI.pdf
- Description:
- IC EEPROM 64KBIT PARALLEL 32PLCC
- Quantity:
- Payment:
- Shipping:
Inventory:4,560
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Product details
Overview
AT28HC64B-12JI from Atmel is a 64 Kbit (8K × 8) parallel EEPROM with JEDEC-standard byte-wide pinout, 120 ns maximum read access time, hardware/software data protection, and industrial temperature range (–40°C to +85°C). It supports page write (1–64 bytes), DATA polling, and toggle-bit write completion detection for embedded firmware storage and configuration retention in microcontroller systems.
For engineers reviewing the AT28HC64B-12JI datasheet, AT28HC64B-12JI pinout, AT28HC64B-12JI application, or AT28HC64B-12JI equivalent, key selection considerations include its 5 V ±10% single-supply operation, CMOS/TTL compatibility, 100 µA standby current, 100,000 write endurance cycles, and support for software data protection via three-byte unlock sequence.
Technical Context
The AT28HC64B-12JI operates as a static RAM-compatible nonvolatile memory: reads require CE and OE low with WE high; writes initiate on WE or CE falling edge with OE high. Its internal 64-byte page register latches address and data, freeing the bus during autonomous internal programming.
Write completion is verified via dual methods: I/O7 complement toggling (DATA polling) or I/O6 state alternation (toggle bit), both usable at any point during tWC. Hardware protection includes VCC sense (<3.8 V inhibit), 5 ms power-on delay, noise filtering (<15 ns pulses ignored), and CE/OE/WE logic-level write inhibition.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Memory Size | 64 Kbit (8,192 × 8), sufficient for boot code, calibration tables, or device configuration in MCU-based systems |
| Read Access Time | 120 ns max - meets timing requirements for 8-bit microcontrollers running at ≤8 MHz with wait-state-free access |
| Page Write Cycle | 10 ms max - enables efficient bulk updates without external timing control or host CPU blocking |
| Endurance | 100,000 write/erase cycles - supports field-updatable firmware storage over multi-year product lifetimes |
| Standby Current | 100 µA CMOS - enables low-power operation in battery-backed or energy-sensitive applications |
| Supply Voltage | 5 V ±10% - compatible with legacy 5 V logic families and mixed-voltage system interfaces |
| Data Retention | 10 years at 85°C - ensures long-term reliability in industrial environments without refresh |
Pinout & Package
AT28HC64B-12JI is packaged in a 28-lead Plastic Dual Inline Package (PDIP) per ordering code suffix "PI", but the "JI" suffix denotes 32-lead Plastic J-Leaded Chip Carrier (PLCC) per Atmel's Ordering Information table (Section 27.1). PLCC package has 32 pins with pins 1 and 17 designated "Don't Connect".
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| A0–A12 | Address Inputs | 13-bit address bus supporting full 8K-word addressing; A6–A12 define page boundaries for 64-byte page writes |
| I/O0–I/O7 | Bidirectional Data Bus | 8-bit parallel interface compatible with standard microcontroller data buses; supports byte and page write operations |
| CE | Chip Enable | Active-low chip select; when high, forces outputs to high-impedance and inhibits all writes regardless of OE/WE state |
| OE | Output Enable | Active-low output control; used with CE to prevent bus contention during read operations |
| WE | Write Enable | Active-low write strobe; falling edge latches address/data for byte or page write initiation |
| VCC, GND | Power Supply | Single 5 V ±10% supply; no separate VPP required for normal operation (12 V only for chip erase or ID area access) |
| NC / DC | No Connect / Don't Connect | Pins 1 and 17 in PLCC are unconnected; must remain floating - not tied to VCC/GND or driven |
Key Features
| Feature | Design Value |
|---|---|
| JEDEC Byte-wide Pinout | Ensures drop-in compatibility with existing 28-pin EPROM/EEPROM sockets and PCB layouts designed for industry-standard parallel memories |
| Software Data Protection | User-configurable 3-byte unlock sequence prevents accidental writes during power transitions or firmware glitches without hardware modification |
| Internal Page Register | 64-byte buffer allows sequential loading of up to 64 bytes within 150 µs intervals, reducing host CPU overhead versus byte-by-byte writes |
| Dual Write Completion Detection | DATA polling (I/O7) and toggle bit (I/O6) provide redundant, bus-compatible methods to avoid polling delays or timeouts in real-time systems |
| Industrial Temperature Range | –40°C to +85°C operation validated across full voltage and timing specs - suitable for automotive under-hood, industrial PLC, and outdoor equipment |
Applications
| Industrial PLC Configuration Storage | Medical Device Calibration Data |
|---|---|
Use Scenario: Storing user-defined I/O mapping, alarm thresholds, and operational parameters in programmable logic controllers deployed in factory automation. IC Role / Device Role / Timing Role: Nonvolatile configuration memory accessed during boot and runtime via 8-bit parallel bus; 120 ns access enables deterministic scan-cycle timing. Use Value: Eliminates need for battery-backed SRAM while maintaining 10-year data retention and 100,000-cycle update capability for field recalibration. | Use Scenario: Holding sensor calibration coefficients, patient history flags, and safety-critical settings in portable diagnostic instruments. IC Role / Device Role / Timing Role: Secure parameter storage with software data protection enabled to prevent corruption during unexpected power loss or ESD events. Use Value: Hardware+software write protection ensures integrity of life-critical calibration data without requiring external supervisory ICs. |
| Automotive Body Control Module | Telecom Equipment Bootloader Storage |
Use Scenario: Retaining seat/mirror position presets, lighting profiles, and fault logs in vehicle body control units operating across extended temperature ranges. IC Role / Device Role / Timing Role: Industrial-grade EEPROM interfaced directly to 8-bit MCU; 100 µA standby current minimizes parasitic drain on vehicle battery. Use Value: Qualified for –40°C to +85°C with 10-year data retention - meets automotive AEC-Q100 stress test expectations for non-safety-critical modules. | Use Scenario: Storing bootloader images and secure boot keys in network switches and base station controllers requiring field-upgradable firmware. IC Role / Device Role / Timing Role: Parallel EEPROM used as primary boot memory; page write mode accelerates firmware patching without halting system operation. Use Value: 10 ms page write cycle enables sub-second firmware updates; DATA polling allows precise synchronization with host processor's interrupt-driven flash management. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar parallel EEPROM applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| ST M28W640ECT | 64 Mbit (8M × 8), 120 ns access, 3.3 V core with 5 V I/O tolerance; requires VPP = 12 V for write | Higher density, lower voltage operation - suited for newer 3.3 V systems with backward-compatible I/O | Select when migrating to lower-power 3.3 V platforms while retaining parallel interface and JEDEC pinout familiarity |
| Microchip 28C64B-25J | 64 Kbit, 250 ns access, 5 V only, no software data protection; PDIP package only | Slower timing, no SDP - appropriate for cost-sensitive, non-security-critical legacy designs | Choose for simple replacement where write protection and fast page write are unnecessary and board space permits larger PDIP footprint |
Compared with AT28HC64B-12JI, the ST M28W640ECT offers higher density and 3.3 V operation but adds complexity with VPP requirement, while the Microchip 28C64B-25J provides basic functionality at lower cost but sacrifices speed, endurance (10K cycles), and data security features critical for modern embedded updates.
Availability
AT28HC64B-12JI is available at Aetrix Electronics and suitable for industrial PLC configuration storage, medical device calibration data retention, and automotive body control module parameter backup requiring stable component supply and long-lifecycle support.
Supply support for AT28HC64B-12JI 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 fabless semiconductor company specializing in microcontrollers, nonvolatile memory, and wireless solutions for embedded systems.
The AT28HC64B product line delivers high-reliability parallel EEPROMs optimized for firmware storage, configuration backup, and calibration data retention in industrial, medical, and automotive applications demanding robust write protection and extended data retention.
FAQ
What is the maximum read access time specified for the AT28HC64B-12JI?
The AT28HC64B-12JI has a maximum read access time of 120 ns, as indicated by the "12" in its part number suffix. This value is guaranteed across the full industrial temperature range (–40°C to +85°C) and 5 V ±10% supply, enabling direct interfacing with 8-bit microcontrollers operating at up to 8 MHz without wait states. The AT28HC64B-12JI datasheet confirms this timing in Section 9 (AC Read Characteristics).
Does the AT28HC64B-12JI require a high-voltage supply for normal write operations?
No, the AT28HC64B-12JI performs all standard byte and page write operations using only the nominal 5 V ±10% VCC supply. A 12 V ±0.5 V supply is required exclusively for chip erase or accessing the 64-byte device identification area (addresses 1FC0H–1FFFH), as documented in Section 4.7 and Figure 18 of the AT28HC64B-12JI datasheet. Normal firmware or configuration updates do not need VPP.
How does software data protection work on the AT28HC64B-12JI?
Software data protection (SDP) on the AT28HC64B-12JI is enabled by writing a specific 3-byte sequence (AAh → 55h → A0h) to addresses 1555h, 0AAAh, and 1555h respectively. Once activated, all subsequent writes require repeating this sequence before data. The AT28HC64B-12JI retains SDP state through power cycles, and disabling requires a different 5-byte sequence (AAh → 55h → 80h → AAh → 20h), per Section 19 and 20 of its datasheet.
What package type does the AT28HC64B-12JI use, and what are its key mechanical features?
The AT28HC64B-12JI uses a 32-lead Plastic J-Leaded Chip Carrier (PLCC) package (ordering code suffix "J"), conforming to JEDEC MS-016, Variation AE. Key features include gull-wing leads, 1.27 mm pitch, 12.3–12.6 mm body width, and pins 1 and 17 designated "Don't Connect". Full dimensions are specified in Section 30.1 of the AT28HC64B-12JI datasheet.
Can the AT28HC64B-12JI be used in place of older EPROMs like the 27C64 without circuit changes?
No - although the AT28HC64B-12JI shares the same 28-pin DIP pinout as the 27C64, it uses a 32-pin PLCC package (suffix "J") and requires different control timing (e.g., WE-based writes vs. VPP-programmed EPROMs). Direct replacement would require PCB redesign. For true 28-pin DIP compatibility, the AT28HC64B-12PI variant should be selected instead, as confirmed in Atmel's Ordering Information table (Section 27.1).
AT28HC64B-12JI 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:
- 10ms
- Access Time:
- 120 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)
AT28HC64B-12JI FAQ
1.How can I place an order for AT28HC64B-12JI through Aetrix?
Please submit a Request for Quotation (RFQ) for AT28HC64B-12JI 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 AT28HC64B-12JI reliable?
The price and inventory of AT28HC64B-12JI are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for AT28HC64B-12JI is usually 5 days.
3.What payment methods are accepted for AT28HC64B-12JI?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for AT28HC64B-12JI transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for AT28HC64B-12JI?
AT28HC64B-12JI orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your AT28HC64B-12JI 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 AT28HC64B-12JI?
For technical support, including AT28HC64B-12JI datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your AT28HC64B-12JI requirements.
6.How does Aetrix verify that AT28HC64B-12JI is sourced from the original manufacturer or authorized distributors?
All AT28HC64B-12JI 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 AT28HC64B-12JI meets industry standards.
7.What is the process for return or replacement of AT28HC64B-12JI?
All AT28HC64B-12JI units undergo pre-shipment inspection (PSI). If there is an issue with AT28HC64B-12JI, 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 AT28HC64B-12JI part is unused and in its original packaging.
Return procedure for AT28HC64B-12JI:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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