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Microchip Technology AT28HC64B-90JU
- Part No.:
- AT28HC64B-90JU
- Manufacturer:
- Microchip Technology
- Category:
- Memory
- Package:
- 32-LCC (J-Lead)
- Datasheet:
-
AT28HC64B-90JU.pdf
- Description:
- IC EEPROM 64KBIT PARALLEL 32PLCC
- Quantity:
- Payment:
- Shipping:
Inventory:105
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Product details
Overview
AT28HC64B-90JU from Atmel is a 64 Kbit (8K × 8) parallel EEPROM with JEDEC-standard byte-wide pinout, 90 ns read access time, hardware/software data protection, and 100,000 write endurance - used in industrial control firmware storage, BIOS configuration backup, and embedded system parameter retention.
For engineers reviewing the AT28HC64B-90JU datasheet, AT28HC64B-90JU pinout, AT28HC64B-90JU application, or AT28HC64B-90JU equivalent, key selection criteria include page-write capability (1–64 bytes), CMOS/TTL compatibility, 5 V ±10% single-supply operation, industrial temperature range (−40°C to +85°C), and PLCC-32 green packaging.
Technical Context
The AT28HC64B-90JU implements a parallel interface with static RAM-like read/write timing, using internal address/data latches for page writes. It supports both byte and page write modes, with automatic internal programming timing controlled by an on-chip timer.
Write completion detection is implemented via dual methods: DATA Polling (I/O7 complement toggle) and Toggle Bit (I/O6 toggling during write). Hardware protection includes VCC sense (<3.8 V inhibit), 5 ms power-on delay, and noise filtering on WE/CE inputs.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Memory Size | 64 Kbit (8,192 × 8), organized as byte-addressable nonvolatile storage |
| Read Access Time | 90 ns maximum - enables direct replacement of SRAM in legacy 8-bit bus systems |
| Page Write Cycle | 10 ms max (standard); supports 1–64-byte burst writes within same page (A6–A12 fixed) |
| Supply Voltage | 5 V ±10% - compatible with standard TTL/CMOS logic rails without level shifting |
| Endurance | 100,000 write/erase cycles - sufficient for field-updatable configuration storage over product lifetime |
| Data Retention | 10 years at 85°C - validated for industrial environments with thermal cycling |
| Standby Current | 100 µA CMOS mode - enables low-power hold states in battery-backed systems |
Pinout & Package
AT28HC64B-90JU is packaged in a 32-lead Plastic J-Leaded Chip Carrier (PLCC), JEDEC MS-016 compliant, Pb/halide-free, with 1.27 mm pitch and 13.4 mm × 13.4 mm body. Pin 1 identifier located at corner with beveled edge.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| A0–A12 | Address Inputs | 13-bit address bus selecting one of 8,192 memory locations (A0 = LSB) |
| I/O0–I/O7 | Bidirectional Data Bus | 8-bit parallel data path for read/write; high-impedance when disabled |
| CE | Chip Enable | Active-low chip select; must be low for any access; inhibits write when high |
| OE | Output Enable | Active-low output control; disables outputs (high-Z) when high during reads |
| WE | Write Enable | Active-low write strobe; initiates byte or page write on falling edge |
| VCC | Power Supply | +5 V ±10% supply; powers core logic and I/O buffers |
| GND | Ground | Reference return for all signals and power |
| NC / DC | No Connect / Don't Connect | Pins 1 and 17 are unconnected; must remain floating per datasheet |
Key Features
| Feature | Design Value |
|---|---|
| 64-byte Page Register | Enables burst writes without external latching; frees address/data bus mid-operation |
| DATA Polling & Toggle Bit | Dual asynchronous write-complete detection eliminates need for fixed delays or external timers |
| Software Data Protection (SDP) | User-configurable lock/unlock via 3-byte command sequence; survives power cycles |
| Hardware Write Inhibit | VCC sense, 5 ms power-on delay, and 15 ns noise filtering prevent spurious writes |
| Extra 64-byte ID Area | Separate EEPROM region (1FC0H–1FFFH) accessible at 12 V for device serialization/tracking |
Applications
| Industrial PLC Firmware Storage | Embedded System Configuration Backup |
|---|---|
Use Scenario: Storing ladder logic firmware and I/O mapping tables in programmable logic controllers operating in harsh factory environments. IC Role / Device Role / Timing Role: Nonvolatile program memory holding executable code and runtime parameters; accessed via 8-bit parallel bus during boot and runtime updates. Use Value: 100,000-cycle endurance and 10-year data retention ensure firmware integrity across decades of maintenance cycles without battery backup. | Use Scenario: Preserving calibration coefficients, user preferences, and network settings in medical infusion pumps and diagnostic equipment. IC Role / Device Role / Timing Role: Parameter EEPROM interfaced directly to microcontroller's data/address bus; retains values across power loss and reset events. Use Value: Software data protection prevents accidental overwrite during firmware updates, while 90 ns read speed supports real-time configuration loading. |
| BIOS/UEFI Configuration Storage | Telecom Line Card Identity & Settings |
Use Scenario: Holding CMOS setup values, boot device order, and security keys in x86-based industrial motherboards. IC Role / Device Role / Timing Role: Parallel EEPROM mapped into CPU I/O space; accessed during POST and runtime via standard ISA-style timing. Use Value: JEDEC byte-wide pinout ensures drop-in compatibility with legacy BIOS designs; 5 V tolerance avoids level-shifter requirements. | Use Scenario: Storing MAC addresses, firmware version stamps, and channel calibration data on telecom line cards operating in central office cabinets. IC Role / Device Role / Timing Role: Identification and settings memory accessed during card initialization and hot-swap detection sequences. Use Value: Industrial temperature rating (−40°C to +85°C) and green PLCC package meet NEBS Level 3 reliability requirements for telecom infrastructure. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar parallel EEPROM applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| AT28HC64B-90SU | Same die, SOIC-28 package; 0.300" wide body; no PLCC mounting footprint | Suitable for surface-mount PCBs with space constraints and reflow-only assembly | Select when board layout requires gull-wing leads and smaller footprint than PLCC-32 |
| MN63C2568F-90 | 64 Kbit parallel EEPROM; 90 ns access; but lacks software data protection and 12 V ID area | Lower-cost option where firmware update safety and device tracking are not required | Choose only if SDP and extra ID memory are unnecessary; verify hardware write-inhibit behavior matches system noise profile |
Compared with AT28HC64B-90SU, the AT28HC64B-90JU offers identical electrical performance but requires PLCC socket or reflow-compatible land pattern; versus MN63C2568F-90, it adds critical reliability features - software lock, VCC-sense write inhibit, and dedicated ID memory - essential for certified industrial deployments.
Availability
AT28HC64B-90JU is available at Aetrix Electronics and suitable for industrial PLC firmware storage, embedded system configuration backup, and BIOS/UEFI settings retention requiring stable component supply across long-lifecycle programs.
Supply support for AT28HC64B-90JU 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 company specializing in microcontrollers, nonvolatile memory, and secure authentication ICs for industrial, automotive, and consumer applications.
The AT28HC64B product line delivers high-reliability parallel EEPROMs optimized for legacy 8-bit bus systems needing fast, robust, and pin-compatible nonvolatile storage - particularly where firmware update safety and long-term data integrity are critical.
FAQ
What is the maximum page write size supported by the AT28HC64B-90JU?
The AT28HC64B-90JU supports page writes of 1 to 64 bytes within a single page boundary defined by address bits A6–A12. All bytes in a given page write must reside on the same page, and successive bytes must be loaded within 150 µs of each other. This capability reduces firmware update time compared to byte-by-byte writes while maintaining deterministic timing.
Does the AT28HC64B-90JU require a 12 V supply for normal operation?
No, the AT28HC64B-90JU operates from a single 5 V ±10% supply during standard read/write operations. The 12 V supply (12.0 V ±0.5 V) is required only for accessing the extra 64-byte device identification area (addresses 1FC0H–1FFFH) - not for main memory access, page writes, or software data protection commands.
How does software data protection (SDP) work on the AT28HC64B-90JU?
SDP on the AT28HC64B-90JU is enabled or disabled via a specific three-byte command sequence written to fixed addresses (1555H, 0AAAH, then 1555H again). Once enabled, all subsequent writes require repeating this sequence before data - ensuring accidental overwrites are blocked. The AT28HC64B-90JU ships with SDP disabled by default.
Can the AT28HC64B-90JU be used as a direct replacement for SRAM in existing designs?
Yes - the AT28HC64B-90JU uses static RAM-compatible timing and pinout (JEDEC byte-wide), allowing read cycles to mirror SRAM behavior. However, write cycles require explicit WE/CE control and write-completion detection (via DATA Polling or Toggle Bit); unlike SRAM, it does not support true concurrent read/write and has finite endurance.
What is the purpose of the NC/DC pins on the AT28HC64B-90JU PLCC package?
Pins 1 and 17 of the AT28HC64B-90JU's 32-lead PLCC package are designated "Don't Connect" (DC) and must remain unconnected - they serve no electrical function and are not bonded internally. Connecting them risks violating absolute maximum ratings or inducing latch-up; the datasheet explicitly prohibits routing traces or soldering to these pins.
AT28HC64B-90JU Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Microchip Technology
- Series:
- -
- Package/Case:
- 32-LCC (J-Lead)
- Packaging:
- Tube
- Product Status:
- Active
- 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:
- 90 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-90JU FAQ
1.How can I place an order for AT28HC64B-90JU through Aetrix?
Please submit a Request for Quotation (RFQ) for AT28HC64B-90JU 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-90JU reliable?
The price and inventory of AT28HC64B-90JU are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for AT28HC64B-90JU is usually 5 days.
3.What payment methods are accepted for AT28HC64B-90JU?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for AT28HC64B-90JU transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for AT28HC64B-90JU?
AT28HC64B-90JU orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your AT28HC64B-90JU 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-90JU?
For technical support, including AT28HC64B-90JU datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your AT28HC64B-90JU requirements.
6.How does Aetrix verify that AT28HC64B-90JU is sourced from the original manufacturer or authorized distributors?
All AT28HC64B-90JU 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-90JU meets industry standards.
7.What is the process for return or replacement of AT28HC64B-90JU?
All AT28HC64B-90JU units undergo pre-shipment inspection (PSI). If there is an issue with AT28HC64B-90JU, 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-90JU part is unused and in its original packaging.
Return procedure for AT28HC64B-90JU:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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