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Microchip Technology AT28HC64BF-90JU
- Part No.:
- AT28HC64BF-90JU
- Manufacturer:
- Microchip Technology
- Category:
- Memory
- Package:
- 32-LCC (J-Lead)
- Datasheet:
-
AT28HC64BF-90JU.pdf
- Description:
- IC EEPROM 64KBIT PARALLEL 32PLCC
- Quantity:
- Payment:
- Shipping:
Inventory:4,487
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Product details
Overview
AT28HC64BF-90JU from Microchip Technology (formerly Atmel) is a 64 Kbit (8K × 8) parallel EEPROM with JEDEC-standard byte-wide pinout, designed for nonvolatile data storage in embedded control and industrial systems. It delivers 90 ns read access time, supports 1–64-byte page writes in ≤2 ms, operates on single 5 V ±10% supply, and features hardware/software data protection for reliable operation across -40°C to +85°C.
For engineers reviewing the AT28HC64BF-90JU datasheet, AT28HC64BF-90JU pinout, AT28HC64BF-90JU application, or AT28HC64BF-90JU equivalent, key selection considerations include its page-write timing, DATA polling and toggle-bit write-completion detection, CMOS/TTL compatibility, industrial temperature rating, and green PLCC-32 packaging.
Technical Context
The AT28HC64BF-90JU implements a static RAM-like interface with no external timing components required: reads occur when CE and OE are low and WE is high; writes initiate on WE or CE low pulse with OE high. Its internal 64-byte page register latches addresses and data, freeing the bus during internal programming.
Write completion is verified via dual methods: DATA polling (I/O7 complement toggles until completion), and toggle-bit detection (I/O6 toggles during write, stabilizes afterward). Hardware protection includes VCC sense (<3.8 V inhibits write), 5 ms power-on delay, noise filtering (<15 ns pulses ignored), and CE/OE/WE logic inhibition.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Memory Size | 64 Kbit (8,192 × 8), organized as byte-addressable parallel array |
| Read Access Time | 90 ns maximum - enables direct replacement of SRAM in legacy 8-bit bus systems |
| Page Write Cycle | ≤2 ms - allows burst programming of up to 64 bytes without CPU wait-state overhead |
| Endurance | 100,000 write/erase cycles - suitable for field-updatable firmware or configuration storage |
| Data Retention | 10 years at 85°C - ensures long-term reliability in unattended industrial deployments |
| Supply Voltage | 5 V ±10% - compatible with standard TTL/CMOS logic rails without regulation |
| Operating Temperature | -40°C to +85°C - certified for industrial-grade environmental stress |
Pinout & Package
AT28HC64BF-90JU is supplied in a 32-lead Plastic J-Leaded Chip Carrier (PLCC) package per JEDEC MS-016, Variation AE. Pin 1 is marked by a corner notch; pins 1 and 17 are No Connect (NC). The device uses a standard JEDEC byte-wide parallel interface with address, data, and control lines.
| 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 operations; high-impedance when disabled |
| CE | Chip Enable | Active-low chip select; must be low for any access; disables outputs when high |
| OE | Output Enable | Active-low output gate; controls data bus drivers during read; high during write |
| WE | Write Enable | Active-low write strobe; initiates byte or page write when CE low and OE high |
| VCC | Power Supply | +5 V ±10% main supply; powers core logic and I/O buffers |
| GND | Ground Reference | Signal and power return plane; decoupling required near VCC pin |
| NC | No Connect | Pins 1 and 17 - must remain unconnected; no internal connection or function |
Key Features
| Feature | Design Value |
|---|---|
| Page Write Operation | Internal 64-byte latch enables burst programming without external address/data hold logic |
| DATA Polling & Toggle Bit | Dual, software-transparent write-completion detection eliminates need for fixed delays or external timers |
| Hardware Write Protection | VCC sensing, 5 ms power-on delay, and noise filtering prevent spurious writes during brown-out or EMI events |
| Software Data Protection (SDP) | User-configurable lock/unlock via 3-byte command sequence; persists through power cycles |
| Extended Identification Area | 64-byte reserved sector (1FC0H–1FFFH) accessible at 12 V on A9 for unique device serialization or calibration data |
Applications
| Industrial PLC Configuration Storage | Medical Device Calibration Data |
|---|---|
Use Scenario: Storing user-defined I/O mapping, scaling factors, and alarm thresholds in programmable logic controllers. IC Role / Device Role / Timing Role: Nonvolatile configuration register accessed via 8-bit parallel bus during boot or runtime reconfiguration. Use Value: 10-year data retention and 100,000-cycle endurance ensure parameter integrity across decades of field operation without battery backup. | Use Scenario: Holding factory-calibrated sensor offsets and gain coefficients in portable diagnostic equipment. IC Role / Device Role / Timing Role: Secure, write-protected memory block accessed only during calibration mode using SDP unlock sequence. Use Value: Software data protection prevents accidental overwrites during routine diagnostics, while 90 ns read speed supports real-time correction lookup. |
| Automotive Body Control Module (BCM) | Legacy Industrial HMI Firmware Patch Storage |
Use Scenario: Storing seat/mirror position presets and lighting profiles in automotive BCMs operating across extended temperature ranges. IC Role / Device Role / Timing Role: Parallel EEPROM interfaced directly to microcontroller's external memory bus; accessed during power-up initialization. Use Value: -40°C to +85°C rating and hardware VCC-sense protection guarantee safe operation during cold cranking and under-hood thermal stress. | Use Scenario: Hosting field-upgradable firmware patches for legacy CNC controllers with no flash update capability. IC Role / Device Role / Timing Role: External code storage mapped into microcontroller's external program space; executed via XIP or copied to RAM. Use Value: 2 ms page write enables rapid patch deployment; DATA polling allows deterministic timing for bootloader handoff without fixed delays. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar parallel EEPROM applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| ST M48T02-90MH6 | Real-time clock + 2 Kbit NV SRAM; no page write; 90 ns access; requires external battery or capacitor | Time-stamped logging vs. pure configuration storage; adds RTC functionality but lacks page write efficiency | Select when timestamped event logging is required; avoid if only nonvolatile parameter storage is needed |
| ON Semiconductor CAT28C64B-90JI | Pin-compatible 64 Kbit parallel EEPROM; identical 90 ns access and 2 ms page write; same PLCC-32 package and JEDEC pinout | No functional deviation; drop-in replacement with identical timing, protection, and endurance specs | Preferred for second-source assurance where Atmel/Microchip supply continuity is a concern |
Compared with ST M48T02-90MH6, AT28HC64BF-90JU provides higher density and faster page writes without RTC overhead; compared with CAT28C64B-90JI, it offers identical performance but different manufacturer qualification and lifecycle support paths.
Availability
AT28HC64BF-90JU is available at Aetrix Electronics and suitable for industrial automation, medical instrumentation, and automotive body electronics requiring stable component supply, long-term data integrity, and JEDEC-compliant parallel memory interfaces.
Supply support for AT28HC64BF-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
Microchip Technology is a global semiconductor company specializing in microcontrollers, analog devices, and nonvolatile memory solutions, with deep heritage in Atmel's legacy product lines including parallel EEPROMs.
The AT28HC64BF series was developed for robust, low-power, industrial-grade nonvolatile storage in resource-constrained 8-bit systems where simplicity, reliability, and long-term data retention are critical design requirements.
FAQ
What is the maximum page write size supported by the AT28HC64BF-90JU?
The AT28HC64BF-90JU supports page write operations of 1 to 64 bytes within a single internal programming cycle. All bytes must reside on the same page, defined by address bits A6–A12. Each subsequent byte must be loaded within 150 µs of the prior one (tBLC); exceeding this window triggers automatic internal programming. This capability reduces firmware overhead versus byte-by-byte writes.
Does the AT28HC64BF-90JU require external circuitry for write completion detection?
No, the AT28HC64BF-90JU provides two built-in, software-accessible methods: DATA polling (monitoring complement state of I/O7) and toggle-bit detection (observing I/O6 toggling). Both operate without external components and can be initiated at any point during the write cycle, enabling deterministic timing control in bare-metal or RTOS environments.
How does hardware write protection function on the AT28HC64BF-90JU?
Hardware protection on the AT28HC64BF-90JU includes four mechanisms: (1) VCC sense disabling writes below ~3.8 V; (2) 5 ms automatic delay after VCC reaches threshold; (3) write inhibition if OE is low, CE is high, or WE is high; and (4) rejection of noise pulses <15 ns on CE/WE. These features collectively prevent corruption during power transients or EMI events.
Can the AT28HC64BF-90JU be used as a direct replacement for SRAM in existing designs?
Yes - the AT28HC64BF-90JU uses a static RAM-compatible interface: CE and OE low with WE high enables read access; no external wait states or timing generators are needed. However, write cycles require software coordination (polling/toggle) and take up to 2 ms, so timing-critical write sequences must account for this latency unlike volatile SRAM.
What is the purpose of the additional 64-byte identification area in the AT28HC64BF-90JU?
The AT28HC64BF-90JU includes an extra 64-byte EEPROM segment (addresses 1FC0H–1FFFH) accessible only when A9 is raised to 12.0 V ±0.5 V. This area is intended for permanent device-specific data such as serial numbers, calibration constants, or manufacturing traceability codes - isolated from main memory to prevent accidental overwrite during normal operation.
AT28HC64BF-90JU 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:
- 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)
AT28HC64BF-90JU FAQ
1.How can I place an order for AT28HC64BF-90JU through Aetrix?
Please submit a Request for Quotation (RFQ) for AT28HC64BF-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 AT28HC64BF-90JU reliable?
The price and inventory of AT28HC64BF-90JU are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for AT28HC64BF-90JU is usually 5 days.
3.What payment methods are accepted for AT28HC64BF-90JU?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for AT28HC64BF-90JU transactions.
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4.How is shipping managed for AT28HC64BF-90JU?
AT28HC64BF-90JU orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your AT28HC64BF-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 AT28HC64BF-90JU?
For technical support, including AT28HC64BF-90JU datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your AT28HC64BF-90JU requirements.
6.How does Aetrix verify that AT28HC64BF-90JU is sourced from the original manufacturer or authorized distributors?
All AT28HC64BF-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 AT28HC64BF-90JU meets industry standards.
7.What is the process for return or replacement of AT28HC64BF-90JU?
All AT28HC64BF-90JU units undergo pre-shipment inspection (PSI). If there is an issue with AT28HC64BF-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 AT28HC64BF-90JU part is unused and in its original packaging.
Return procedure for AT28HC64BF-90JU:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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