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Microchip Technology AT28HC64B-90SU
- Part No.:
- AT28HC64B-90SU
- Manufacturer:
- Microchip Technology
- Category:
- Memory
- Package:
- 28-SOIC (0.295", 7.50mm Width)
- Datasheet:
-
AT28HC64B-90SU.pdf
- Description:
- IC EEPROM 64KBIT PARALLEL 28SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:315
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Product details
Overview
AT28HC64B-90SU from Microchip Technology (formerly 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 page write capability supporting up to 64-byte writes in ≤10 ms. It operates from a single 5 V ±10% supply and is used in industrial control firmware storage, BIOS configuration backup, and embedded system parameter retention.
For engineers reviewing the AT28HC64B-90SU datasheet, AT28HC64B-90SU pinout, AT28HC64B-90SU application, or AT28HC64B-90SU equivalent, key selection criteria include page write timing (10 ms max), CMOS/TTL compatibility, DATA polling & toggle bit for write completion detection, industrial temperature range (−40°C to +85°C), and green SOIC-28 packaging.
Technical Context
The AT28HC64B-90SU implements a parallel interface with independent CE/OE/WE controls enabling SRAM-like read/write operation without external logic. Its internal 64-byte page register latches address and data during page writes, freeing the bus for concurrent operations.
Write completion is verified via dual methods: DATA polling (I/O7 complement inversion) and toggle bit (I/O6 toggling), both functional across the full write cycle. 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), sufficient for firmware patches or calibration tables in microcontroller systems |
| Read Access Time | 90 ns maximum - meets timing budgets for 8-bit microprocessor buses running ≤11 MHz |
| Page Write Cycle | 10 ms maximum - enables burst configuration updates without host CPU blocking |
| Supply Voltage | 5 V ±10% - compatible with legacy 5 V logic families and mixed-voltage board designs |
| Standby Current | 100 µA CMOS - supports low-power sleep modes in battery-backed applications |
| Endurance | 100,000 write/erase cycles - suitable for field-upgradable systems requiring frequent parameter updates |
| Data Retention | 10 years at 85°C - ensures long-term reliability in industrial environments |
Pinout & Package
AT28HC64B-90SU is packaged in a 28-lead SOIC (28S) with 0.300" body width, JEDEC MS-013 compliant, green (Pb/halide-free) construction.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| A0–A12 | Address Inputs | 13-bit address bus selecting one of 8,192 memory locations; A6–A12 define page boundaries for 64-byte writes |
| I/O0–I/O7 | Bidirectional Data Bus | 8-bit parallel data path; supports true read/write without direction control pins |
| CE | Chip Enable | Active-low chip select; must be low with OE low and WE high for read access |
| OE | Output Enable | Active-low output gate; controls data bus tristate during reads and write polling |
| WE | Write Enable | Active-low write strobe; falling edge latches address/data for byte or page write |
| VCC | Power Supply | +5 V ±10% supply; powers core logic and I/O buffers |
| GND | Ground | Reference return path for all signals and power |
| NC | No Connect | Unbonded pins (pins 1, 14, 27); must remain unconnected per datasheet |
Key Features
| Feature | Design Value |
|---|---|
| 64-byte Page Write | Reduces firmware update time by 64× vs. byte writes; eliminates host-side write-loop overhead |
| DATA Polling & Toggle Bit | Enables real-time write status monitoring without dedicated interrupt lines or timers |
| Software Data Protection (SDP) | User-configurable write lock using 3-byte command sequence; survives power cycles and protects during brown-out |
| Hardware Write Inhibit | VCC sense + 5 ms power-on delay prevents spurious writes during power ramp-up |
| Device Identification Area | Dedicated 64-byte EEPROM region (1FC0H–1FFFH) accessible at 12 V for serialization or calibration data |
Applications
| Industrial PLC Configuration Storage | Embedded System Bootloader Parameter Backup |
|---|---|
Use Scenario: Storing I/O mapping, PID tuning constants, and alarm thresholds in programmable logic controllers operating in factory-floor environments. IC Role / Device Role / Timing Role: Nonvolatile configuration register accessed during startup and runtime via parallel bus; 90 ns read latency aligns with microcontroller wait-state requirements. Use Value: Ensures deterministic boot behavior after power loss; 100,000-cycle endurance supports weekly firmware updates over 10+ years. | Use Scenario: Preserving bootloader version, secure boot keys, and hardware revision flags in medical device microcontrollers with strict regulatory traceability. IC Role / Device Role / Timing Role: Dedicated parameter EEPROM interfaced directly to MCU data/address bus; software data protection prevents accidental corruption during field upgrades. Use Value: Eliminates need for external write-protection hardware; 10-year data retention satisfies FDA 21 CFR Part 11 archival requirements. |
| Automotive ECU Calibration Memory | Point-of-Sale Terminal Firmware Patch Storage |
Use Scenario: Holding engine calibration maps and emission control parameters in aftermarket ECUs where reprogramming occurs in service bays. IC Role / Device Role / Timing Role: Parallel EEPROM mapped into MCU memory space; page write mode enables rapid map uploads via diagnostic port. Use Value: 10 ms page write time reduces calibration session duration by >95% vs. byte writes; industrial temp range covers under-hood thermal cycling. | Use Scenario: Storing localized language packs, tax rate tables, and receipt format templates in retail terminals deployed globally. IC Role / Device Role / Timing Role: Standalone configuration store accessed only during initialization; CMOS standby current <100 µA extends battery life during transport/storage. Use Value: Green SOIC-28 package complies with RoHS/REACH; JEDEC pinout ensures drop-in replacement across legacy terminal designs. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar parallel EEPROM applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| AT28C64B-90PU | Same 64K × 8 architecture and 90 ns speed, but uses PDIP-28 package instead of SOIC-28; no green packaging option | Preferred for through-hole prototyping or legacy PCBs with DIP footprints; lacks surface-mount thermal performance | Select when mechanical mounting or hand-soldering is required; verify board layout accommodates 0.600" DIP width |
| ST M48T02-90MH6 | 64K × 8 NV SRAM with integrated lithium battery and real-time clock; 90 ns access but requires battery management | Used where nanosecond write latency and RTC functionality are critical; not a direct EEPROM replacement due to different write mechanism | Choose only if simultaneous timekeeping and nonvolatile storage are needed; avoid for pure configuration storage due to battery lifetime constraints |
Compared with AT28HC64B-90SU, AT28C64B-90PU offers identical electrical behavior but different mechanical fit, while ST M48T02-90MH6 trades EEPROM endurance for RTC integration and zero-write-latency - making it unsuitable for high-cycle parameter logging but viable for timestamped event logging.
Availability
AT28HC64B-90SU is available at Aetrix Electronics and suitable for industrial control systems, embedded medical devices, and automotive diagnostics equipment requiring stable component supply, long-lifecycle support, and RoHS-compliant packaging.
Supply support for AT28HC64B-90SU 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 acquired Atmel in 2016 and maintains full support for legacy Atmel EEPROM products including the AT28HC64B family.
The AT28HC64B product line was designed for reliable, low-pin-count parallel nonvolatile storage in resource-constrained embedded systems where SRAM-like interface simplicity and robust write protection are essential.
FAQ
What is the maximum page write cycle time for AT28HC64B-90SU?
The AT28HC64B-90SU has a maximum page write cycle time of 10 ms under standard operation. This value is guaranteed across the full industrial temperature range (−40°C to +85°C) and applies to all 1–64 byte writes within a single page. The datasheet notes an optional faster variant (AT28HC64BF) achieves 2 ms, but that is not applicable to the AT28HC64B-90SU.
Does AT28HC64B-90SU support both hardware and software write protection?
Yes, AT28HC64B-90SU implements dual-layer protection: hardware features include VCC sensing (<3.8 V inhibit), 5 ms power-on delay, and noise filtering on WE/CE inputs; software protection uses a user-programmable 3-byte command sequence to enable/disable write locks. Both mechanisms operate independently and persist across power cycles, ensuring robust defense against accidental writes in AT28HC64B-90SU deployments.
Can AT28HC64B-90SU be used with 3.3 V microcontrollers?
No, AT28HC64B-90SU requires a 5 V ±10% supply and is not 3.3 V tolerant. Its inputs are CMOS/TTL compatible but specified only for 5 V logic levels (VIH = 2.0 V min, VIL = 0.8 V max). Interfacing with 3.3 V microcontrollers requires level-shifting circuitry on address, data, and control lines to prevent damage and ensure reliable operation of AT28HC64B-90SU.
How is write completion detected on AT28HC64B-90SU?
AT28HC64B-90SU provides two independent methods: DATA polling monitors I/O7 - it outputs the complement of the last written byte until completion, then returns true data; toggle bit monitors I/O6 - it toggles between 0 and 1 during writes and stops toggling upon completion. Both methods are usable at any time during the write cycle and require no additional hardware, simplifying host firmware for AT28HC64B-90SU integration.
What package type does AT28HC64B-90SU use?
AT28HC64B-90SU uses a 28-lead SOIC (Small Outline Integrated Circuit) package designated as 28S, with 0.300" body width, JEDEC MS-013 compliant dimensions, and green (Pb/halide-free) finish. Pin 1 is marked by a notch or beveled corner; NC pins (1, 14, 27) must remain unconnected per the AT28HC64B-90SU datasheet.
AT28HC64B-90SU Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Microchip Technology
- Series:
- -
- Package/Case:
- 28-SOIC (0.295", 7.50mm Width)
- Packaging:
- Tube
- Product Status:
- Active
- Programmable:
- 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-SOIC
AT28HC64B-90SU FAQ
1.How can I place an order for AT28HC64B-90SU through Aetrix?
Please submit a Request for Quotation (RFQ) for AT28HC64B-90SU 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-90SU reliable?
The price and inventory of AT28HC64B-90SU are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for AT28HC64B-90SU is usually 5 days.
3.What payment methods are accepted for AT28HC64B-90SU?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for AT28HC64B-90SU transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for AT28HC64B-90SU?
AT28HC64B-90SU orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your AT28HC64B-90SU 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-90SU?
For technical support, including AT28HC64B-90SU datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your AT28HC64B-90SU requirements.
6.How does Aetrix verify that AT28HC64B-90SU is sourced from the original manufacturer or authorized distributors?
All AT28HC64B-90SU 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-90SU meets industry standards.
7.What is the process for return or replacement of AT28HC64B-90SU?
All AT28HC64B-90SU units undergo pre-shipment inspection (PSI). If there is an issue with AT28HC64B-90SU, 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-90SU part is unused and in its original packaging.
Return procedure for AT28HC64B-90SU:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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