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Microchip Technology AT28HC64B-90JI
- Part No.:
- AT28HC64B-90JI
- Manufacturer:
- Microchip Technology
- Category:
- Memory
- Package:
- 32-LCC (J-Lead)
- Datasheet:
-
AT28HC64B-90JI.pdf
- Description:
- IC EEPROM 64KBIT PARALLEL 32PLCC
- Quantity:
- Payment:
- Shipping:
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Product details
Overview
AT28HC64B-90JI from Atmel is a 64 Kbit (8K × 8) parallel EEPROM with JEDEC-standard byte-wide pinout, 90 ns read access time, single 5 V ±10% supply, and industrial temperature range (–40°C to +85°C). It supports hardware/software data protection, DATA polling and toggle-bit write completion detection, and 1–64-byte page writes for embedded system configuration storage.
For engineers reviewing the AT28HC64B-90JI datasheet, AT28HC64B-90JI pinout, AT28HC64B-90JI application, or AT28HC64B-90JI equivalent, key selection criteria include verified 90 ns tACC timing, CMOS/TTL-compatible I/O, 100 µA standby current, JEDEC-compliant 28-pin SOIC (SOIC-28) package, and software data protection enable/disable command sequences.
Technical Context
The AT28HC64B-90JI operates as a drop-in SRAM-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 during page write, freeing the bus for concurrent operations.
Write completion is confirmed via dual methods: DATA polling (I/O7 complement → true data transition) and toggle-bit detection (I/O6 toggling ceases post-write). 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-level inhibition.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Memory Size | 64 Kbit (8,192 × 8 bits); sufficient for firmware boot code, calibration tables, or device configuration in microcontroller-based systems. |
| Read Access Time (tACC) | 90 ns maximum; enables direct replacement of fast SRAM in legacy 8-bit bus architectures without timing redesign. |
| Page Write Cycle Time | 10 ms maximum (standard); allows efficient bulk updates of up to 64 bytes per write cycle, reducing host CPU overhead vs. byte-by-byte writes. |
| VCC Supply | 5 V ±10%; eliminates need for dedicated voltage regulators in 5 V logic systems, simplifying power design. |
| Standby Current (ISB1) | 100 µA maximum at CMOS levels; critical for low-power battery-backed applications such as metering or sensor nodes. |
| Endurance & Retention | 100,000 write/erase cycles and 10-year data retention; validated for long-life industrial control and automotive body electronics. |
| Operating Temperature | –40°C to +85°C; qualified for deployment in harsh industrial environments without derating. |
Pinout & Package
AT28HC64B-90JI is packaged in a 28-lead, 0.300" wide plastic gull-wing small outline (SOIC-28) per JEDEC MS-013, with pin 1 marked by notch or bevel. Pin functions are electrically identical across PDIP, PLCC, and TSOP variants.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| A0–A12 | Address Inputs | 13-bit address bus (0–8191) selecting one of 8K bytes; A6–A12 define page boundaries for 64-byte page writes. |
| I/O0–I/O7 | Bidirectional Data Bus | 8-bit parallel interface compatible with 8051, Z80, and 68K families; supports true read/write without external transceivers. |
| CE | Chip Enable | Active-low chip select; when high, forces outputs to high-impedance and inhibits all writes - essential for bus arbitration. |
| OE | Output Enable | Active-low output control; used with CE to prevent bus contention during multi-device reads. |
| WE | Write Enable | Active-low write strobe; falling edge latches address/data; must be high during reads to avoid unintended writes. |
| GND / VCC | Power Terminals | Single 5 V supply with decoupling required within 1 cm; no separate VPP or programming voltage needed. |
Key Features
| Feature | Design Value |
|---|---|
| JEDEC Byte-wide Pinout | Direct compatibility with legacy 8-bit microprocessor buses (e.g., 8085, 6800), eliminating adapter logic or PCB redesign. |
| Software Data Protection (SDP) | User-enabled/disabled via 3-byte command sequence (AAh/55h/A0h for enable); prevents accidental writes during power transitions without hardware mods. |
| DATA Polling & Toggle Bit | Real-time write status feedback via I/O7 or I/O6 - removes need for fixed delays or external timers in host firmware. |
| 64-byte Page Write | Reduces write latency by >98% vs. 64 individual byte writes; internal latching frees address/data bus for other tasks during programming. |
| Hardware Write Inhibit | VCC sense, 5 ms power-up delay, and noise filtering ensure zero inadvertent writes during brown-out or EMI events. |
Applications
| Industrial PLC Configuration Storage | Medical Device Calibration Data |
|---|---|
|
Use Scenario: Storing I/O mapping, PID tuning parameters, and alarm thresholds in programmable logic controllers deployed in factory automation. IC Role / Device Role / Timing Role: Nonvolatile configuration memory accessed during boot and runtime; requires 90 ns read speed to meet scan-cycle deadlines. Use Value: 100,000-cycle endurance ensures reliable parameter updates over 10+ years of daily reconfiguration; 100 µA standby current extends backup battery life. |
Use Scenario: Holding calibrated sensor offsets, gain coefficients, and patient-specific therapy settings in portable infusion pumps and diagnostic monitors. IC Role / Device Role / Timing Role: Secure, tamper-resistant storage with software data protection enabled to prevent unauthorized parameter changes. Use Value: SDP command sequence blocks accidental writes during ESD events or power glitches; 10-year data retention meets FDA regulatory requirements. |
| Automotive Body Control Module (BCM) | Point-of-Sale Terminal Firmware |
|
Use Scenario: Storing seat/mirror position presets, lighting profiles, and door lock configurations in BCMs operating across –40°C to +85°C. IC Role / Device Role / Timing Role: Industrial-grade EEPROM interfaced directly to 8-bit MCU bus; leverages hardware write inhibit for robustness during vehicle cranking. Use Value: VCC sense and 5 ms power-on delay prevent corruption during 5 V rail collapse; green (Pb/Halide-free) packaging satisfies automotive RoHS compliance. |
Use Scenario: Hosting bootloader code, encryption keys, and transaction log metadata in retail terminals subject to frequent firmware updates. IC Role / Device Role / Timing Role: High-reliability parallel EEPROM supporting rapid field upgrades via page write; accessed during cold boot before OS initialization. Use Value: 10 ms page write cycle enables full 64-byte patch application in <15 ms; DATA polling eliminates host-side timing uncertainty. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar parallel EEPROM applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| ST M28W640ECB90N6 | 64 Mbit (8M × 8), 90 ns, 3.3 V core with 5 V tolerant I/O; larger density but incompatible voltage domain. | Requires level-shifting in 5 V systems; suited for newer designs migrating to 3.3 V logic. | Select only if upgrading to higher density and redesigning power architecture. |
| Microchip 28C64B-25/P | 64 Kbit, 250 ns access, PDIP-28 package; no page write, no software protection, higher 5 mA standby current. | Limited to cost-sensitive, low-speed applications where write efficiency and security are not critical. | Choose only for legacy board replacements where timing margin exists and SDP is unnecessary. |
Compared with ST M28W640ECB90N6 and Microchip 28C64B-25/P, the AT28HC64B-90JI uniquely delivers 90 ns speed, 64-byte page write, and software data protection in a pin-compatible 5 V SOIC-28 package - making it the only option for secure, high-speed, drop-in upgrades in existing 5 V industrial designs.
Availability
AT28HC64B-90JI 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 across extended product lifecycles.
Supply support for AT28HC64B-90JI 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 secure authentication ICs for industrial, automotive, and consumer markets.
The AT28HC64B product line was designed for high-reliability, SRAM-compatible parallel EEPROM applications in legacy 8-bit systems requiring fast read access, robust write protection, and long-term data integrity without external programming voltage.
FAQ
What is the maximum read access time specified for the AT28HC64B-90JI?
The AT28HC64B-90JI has a guaranteed maximum read access time (tACC) of 90 ns under industrial temperature conditions (–40°C to +85°C) and 5 V ±10% supply. This value is measured from address valid to valid data on I/O0–I/O7 and is fully characterized per the official Atmel datasheet revision 0274K–PEEPR–8/08. The AT28HC64B-90JI meets this specification in its SOIC-28 package without derating.
Does the AT28HC64B-90JI require an external programming voltage (VPP) for write operations?
No, the AT28HC64B-90JI does not require an external VPP voltage. All write operations - including byte and page writes - are performed using only the standard 5 V ±10% VCC supply. Internal charge pumps generate necessary high-voltage programming signals, eliminating the need for external VPP circuitry or dedicated programming hardware. This simplifies system design and reduces BOM cost for the AT28HC64B-90JI.
How is software data protection (SDP) enabled and disabled on the AT28HC64B-90JI?
SDP is enabled on the AT28HC64B-90JI by writing three specific bytes (AAh to address 1555h, 55h to address 0AAAh, then A0h to address 1555h) followed by any write to activate protection. Disabling SDP requires a five-byte sequence (AAh/55h/80h/AAh/20h to address 1555h, then 55h to 0AAAh). These commands are defined in the AT28HC64B-90JI datasheet and do not alter user memory contents.
What package type is used for the AT28HC64B-90JI, and is it JEDEC-compliant?
The AT28HC64B-90JI uses a 28-lead, 0.300" wide plastic gull-wing small outline (SOIC-28) package, designated as "SI" in Atmel's ordering nomenclature. It conforms to JEDEC standard MS-013 and features a JEDEC-approved byte-wide pinout identical to industry-standard SRAMs - ensuring mechanical and electrical compatibility with existing SOIC-28 footprints and socketing solutions for the AT28HC64B-90JI.
Can the AT28HC64B-90JI be used in place of faster or slower speed grades like the -70 or -120 versions?
Yes, the AT28HC64B-90JI is pin- and function-compatible with the -70JI and -120JI variants. While the -70JI guarantees 70 ns access and the -120JI guarantees 120 ns, the -90JI's 90 ns rating provides timing headroom between them. System timing margins must be verified per design, but no PCB or firmware changes are required to substitute the AT28HC64B-90JI into circuits originally specified for other speed grades in the same package.
AT28HC64B-90JI 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)
AT28HC64B-90JI FAQ
1.How can I place an order for AT28HC64B-90JI through Aetrix?
Please submit a Request for Quotation (RFQ) for AT28HC64B-90JI 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-90JI reliable?
The price and inventory of AT28HC64B-90JI are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for AT28HC64B-90JI is usually 5 days.
3.What payment methods are accepted for AT28HC64B-90JI?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for AT28HC64B-90JI transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for AT28HC64B-90JI?
AT28HC64B-90JI orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your AT28HC64B-90JI 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-90JI?
For technical support, including AT28HC64B-90JI datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your AT28HC64B-90JI requirements.
6.How does Aetrix verify that AT28HC64B-90JI is sourced from the original manufacturer or authorized distributors?
All AT28HC64B-90JI 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-90JI meets industry standards.
7.What is the process for return or replacement of AT28HC64B-90JI?
All AT28HC64B-90JI units undergo pre-shipment inspection (PSI). If there is an issue with AT28HC64B-90JI, 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-90JI part is unused and in its original packaging.
Return procedure for AT28HC64B-90JI:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
AT28HC64B-90JI Tags
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