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Microchip Technology AT28HC64B-90TU
- Part No.:
- AT28HC64B-90TU
- Manufacturer:
- Microchip Technology
- Category:
- Memory
- Package:
- 28-TSSOP (0.465", 11.80mm Width)
- Datasheet:
-
AT28HC64B-90TU.pdf
- Description:
- IC EEPROM 64KBIT PARALLEL 28TSOP
- Quantity:
- Payment:
- Shipping:
Inventory:1,265
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Product details
Overview
AT28HC64B-90TU from Atmel is a 64 Kbit (8K × 8) parallel EEPROM with JEDEC-standard byte-wide pinout, 90 ns read access time, page write capability (1–64 bytes), and hardware/software data protection - used in industrial control firmware storage, BIOS configuration backup, and embedded system parameter retention.
For engineers reviewing the AT28HC64B-90TU datasheet, AT28HC64B-90TU pinout, AT28HC64B-90TU application, or AT28HC64B-90TU equivalent, key selection criteria include 5 V ±10% single-supply operation, CMOS/TTL compatibility, DATA polling & toggle-bit write completion detection, and industrial temperature range (−40°C to +85°C).
Technical Context
The AT28HC64B-90TU implements a parallel interface with static RAM-like read/write timing, eliminating external address latches. Its internal 64-byte page register enables burst writes without bus hold, while automatic internal write timing eliminates external programming pulses.
Write cycle termination is confirmed via dual methods: DATA polling on I/O7 (complement-to-data during write, true data after completion) and toggle-bit behavior on I/O6. 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 - defines minimum clock period for synchronous read interfaces |
| Page Write Cycle | 10 ms maximum - determines worst-case firmware update latency per 64-byte block |
| Supply Voltage | 5 V ±10% - compatible with legacy 5 V logic systems without level shifting |
| Standby Current | 100 µA CMOS - enables low-power retention in battery-backed applications |
| Endurance | 100,000 write/erase cycles - supports field-upgradable calibration data logging |
| Data Retention | 10 years at 85°C - ensures long-term reliability in industrial environments |
Pinout & Package
AT28HC64B-90TU is supplied in a 28-lead Thin Small Outline Package (TSOP), JEDEC MO-183 compliant, 8 mm × 13.4 mm body, 0.55 mm lead pitch. Pin 1 identifier located at top-left corner with beveled edge marking.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| A0–A12 | Address Inputs | 13-bit address bus selecting one of 8,192 memory locations |
| I/O0–I/O7 | Bidirectional Data Bus | Byte-wide parallel interface for read/write operations; TTL/CMOS compatible |
| CE | Chip Enable | Active-low chip select; disables outputs and inhibits writes when high |
| OE | Output Enable | Active-low output gate; controls data bus tristate during reads only |
| 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 memory array |
| GND | Ground | Reference return path for all signals and power |
| NC | No Connect | Unbonded pins (TSOP pins 1, 14, 27, 28); must remain unconnected |
Key Features
| Feature | Design Value |
|---|---|
| Page Write Operation | Writes 1–64 bytes in single 10 ms cycle - reduces firmware update time vs. byte-by-byte writes |
| DATA Polling & Toggle Bit | Dual asynchronous write-completion detection - eliminates need for fixed delays or external timers |
| Software Data Protection (SDP) | User-configurable 3-byte command sequence prevents accidental writes - critical for field-deployed systems |
| Hardware Write Inhibit | VCC sense, power-on delay, and noise filtering prevent spurious writes during power transitions |
| Device Identification Area | 64-byte reserved EEPROM region (1FC0H–1FFFH) accessible at 12 V - supports unique device serialization |
Applications
| Industrial PLC Configuration Storage | Embedded System Bootloader Parameter Backup |
|---|---|
Use Scenario: Storing calibrated sensor offsets, I/O mapping, and runtime configuration in programmable logic controllers operating in harsh factory environments. IC Role / Device Role / Timing Role: Nonvolatile parameter storage with guaranteed 10-year data retention at 85°C and 100,000-cycle endurance. Use Value: Eliminates need for battery-backed SRAM; withstands repeated power cycling and thermal stress without data loss. | Use Scenario: Preserving bootloader settings (boot device priority, debug enable, secure boot keys) across reboots and firmware updates in medical and industrial edge devices. IC Role / Device Role / Timing Role: Secure, software-protected configuration register - accessed during early boot before main CPU initialization. Use Value: SDP prevents corruption during brown-out events; 90 ns read speed ensures minimal boot latency. |
| Legacy Industrial Equipment Firmware Patching | Automotive Diagnostic Module Calibration Data |
Use Scenario: Field-upgrading microcontroller firmware in aging CNC machines using RS-232-connected service tools. IC Role / Device Role / Timing Role: Parallel EEPROM interfaced directly to 8-bit microcontroller address/data bus - no glue logic required. Use Value: Page write reduces patch time by >95% vs. byte writes; JEDEC pinout ensures drop-in replacement for obsolete parts. | Use Scenario: Storing vehicle-specific calibration tables (fuel trim, throttle position offset) in OBD-II diagnostic modules subject to automotive temperature cycling. IC Role / Device Role / Timing Role: High-reliability nonvolatile memory qualified for −40°C to +85°C operation with 100,000-cycle endurance. Use Value: Meets AEC-Q100 stress requirements for data integrity over 15+ year vehicle lifetime. |
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 only, no software protection | Larger capacity but incompatible voltage and missing SDP - requires redesign for 3.3 V and new protection scheme | Choose only if higher density and 3.3 V operation are mandatory; not a functional substitute |
| Microchip 28C64B-25J | Same 64 Kbit, 250 ns access, 5 V, PLCC-32 package, no page write or SDP | Slower timing and no page write - increases firmware update time; lacks software lockout | Acceptable for cost-sensitive, low-update-frequency applications where speed and protection are secondary |
Compared with ST M28W640ECT and Microchip 28C64B-25J, the AT28HC64B-90TU delivers optimal balance of speed (90 ns), page write efficiency, and dual-layer (hardware + software) write protection - making it the preferred choice for industrial firmware and configuration storage where reliability and update agility are critical.
Availability
AT28HC64B-90TU is available at Aetrix Electronics and suitable for industrial control systems, embedded bootloader design, and automotive diagnostic module manufacturing requiring stable component supply and long-term lifecycle support.
Supply support for AT28HC64B-90TU 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 security ICs for industrial, automotive, and consumer applications.
The AT28HC64B product line was designed for high-reliability, pin-compatible replacement of EPROM and battery-backed SRAM in legacy 5 V systems - emphasizing ease of integration, data integrity, and long-term manufacturability.
FAQ
What is the maximum page write cycle time for AT28HC64B-90TU?
The AT28HC64B-90TU has a maximum page write cycle time of 10 ms under standard conditions. This value is specified in the AC characteristics table and applies to all page sizes (1–64 bytes). The device does not support the optional 2 ms cycle time - that feature is exclusive to the AT28HC64BF variant, which is not interchangeable with the AT28HC64B-90TU.
Does AT28HC64B-90TU support both hardware and software data protection?
Yes, the AT28HC64B-90TU implements dual-layer protection: hardware features include VCC sensing (<3.8 V inhibit), 5 ms power-on delay, and 15 ns noise filtering on WE/CE; software protection uses a user-configurable 3-byte command sequence (AAh/55h/A0h) to enable/disable write lock. Both mechanisms operate independently and are fully active in the AT28HC64B-90TU.
What package type is used for AT28HC64B-90TU?
The AT28HC64B-90TU is packaged in a 28-lead Plastic Thin Small Outline Package (TSOP), designated as 28T per Atmel's ordering information. It measures 8 mm × 13.4 mm with 0.55 mm lead pitch and conforms to JEDEC MO-183 standards. Pins 1, 14, 27, and 28 are NC and must remain unconnected.
Can AT28HC64B-90TU be used in place of AT28HC64B-70TU?
Yes - the AT28HC64B-90TU is functionally identical to the AT28HC64B-70TU except for its 90 ns (vs. 70 ns) read access time. All pinouts, voltage specifications, timing parameters (except tACC/tCE), and features including page write, DATA polling, and software protection are identical. System timing margins should be verified, but no PCB or firmware changes are required.
How is write completion detected on AT28HC64B-90TU?
Write completion on the AT28HC64B-90TU is detected using two independent methods: (1) DATA polling - reading the last written byte returns complemented data until completion, then true data; (2) Toggle bit - I/O6 toggles between 0 and 1 during write and stabilizes after completion. Both methods are fully supported and documented in the AT28HC64B-90TU datasheet.
AT28HC64B-90TU Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Microchip Technology
- Series:
- -
- Package/Case:
- 28-TSSOP (0.465", 11.80mm Width)
- Packaging:
- Tray
- 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:
- 28-TSOP
AT28HC64B-90TU FAQ
1.How can I place an order for AT28HC64B-90TU through Aetrix?
Please submit a Request for Quotation (RFQ) for AT28HC64B-90TU 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-90TU reliable?
The price and inventory of AT28HC64B-90TU are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for AT28HC64B-90TU is usually 5 days.
3.What payment methods are accepted for AT28HC64B-90TU?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for AT28HC64B-90TU transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for AT28HC64B-90TU?
AT28HC64B-90TU orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your AT28HC64B-90TU 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-90TU?
For technical support, including AT28HC64B-90TU datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your AT28HC64B-90TU requirements.
6.How does Aetrix verify that AT28HC64B-90TU is sourced from the original manufacturer or authorized distributors?
All AT28HC64B-90TU 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-90TU meets industry standards.
7.What is the process for return or replacement of AT28HC64B-90TU?
All AT28HC64B-90TU units undergo pre-shipment inspection (PSI). If there is an issue with AT28HC64B-90TU, 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-90TU part is unused and in its original packaging.
Return procedure for AT28HC64B-90TU:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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