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Microchip Technology AT28HC64B-90SI
- Part No.:
- AT28HC64B-90SI
- Manufacturer:
- Microchip Technology
- Category:
- Memory
- Package:
- 28-SOIC (0.295", 7.50mm Width)
- Datasheet:
-
AT28HC64B-90SI.pdf
- Description:
- IC EEPROM 64KBIT PARALLEL 28SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:1,471
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Product details
Overview
AT28HC64B-90SI 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, page write (1–64 bytes), DATA polling, and toggle-bit write completion detection - used in embedded system configuration storage and firmware parameter retention.
For engineers reviewing the AT28HC64B-90SI datasheet, AT28HC64B-90SI pinout, AT28HC64B-90SI application, or AT28HC64B-90SI equivalent, key selection considerations include page write timing (10 ms max), CMOS/TTL compatibility, 100 µA standby current, and software data protection enable/disable sequences.
Technical Context
The AT28HC64B-90SI implements a parallel interface with independent CE/OE/WE control logic enabling SRAM-like read/write cycles without external timing components. 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 mechanisms: 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), sufficient for boot code flags, calibration tables, or device ID storage |
| Read Access Time | 90 ns maximum - meets timing for 11 MHz bus systems with margin |
| Page Write Cycle | 10 ms maximum - enables burst programming of up to 64 bytes per cycle |
| Supply Voltage | 5 V ±10% - compatible with legacy 5 V logic rails and mixed-voltage designs |
| Standby Current | 100 µA CMOS - supports low-power sleep modes in battery-backed systems |
| Endurance | 100,000 write/erase cycles - suitable for field-updatable configuration data |
| Data Retention | 10 years at 85°C - ensures long-term reliability in industrial environments |
Pinout & Package
AT28HC64B-90SI uses a 28-lead SOIC (28S) package with JEDEC-standard byte-wide pinout and industrial temperature rating (−40°C to +85°C).
| 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 | 8-bit parallel interface for read/write data transfer; 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 drivers during read cycles only |
| WE | Write Enable | Active-low write strobe; initiates byte or page write on falling edge |
| VCC | Power Supply | +5 V ±10% main supply; powers core logic and I/O buffers |
| GND | Ground Reference | Signal and power return path; required for stable operation and noise immunity |
| NC | No Connect | Unbonded pin; must remain unconnected per datasheet (pins 1, 17 in PLCC variant) |
Key Features
| Feature | Design Value |
|---|---|
| Page Write Operation | Writes 1–64 bytes in a single internal cycle (max 10 ms), reducing host CPU overhead vs. byte-by-byte writes |
| Software Data Protection | User-configurable lock/unlock via 3-byte command sequence (AAh/55h/A0h), preventing accidental writes during power transitions |
| DATA Polling & Toggle Bit | Real-time write status feedback via I/O7 complement or I/O6 toggling - eliminates need for fixed delays or external timers |
| Hardware Write Inhibit | VCC sense, 5 ms power-on delay, and 15 ns noise filtering prevent spurious writes during brown-out or EMI events |
| Device Identification Area | 64-byte reserved sector (1FC0H–1FFFH) accessible with 12 V on A9 - enables unique device serialization or firmware version tracking |
Applications
| Industrial PLC Configuration Storage | Medical Device Calibration Data |
|---|---|
Use Scenario: Storing I/O mapping, alarm thresholds, and operational parameters in programmable logic controllers deployed in factory automation. IC Role / Device Role / Timing Role: Nonvolatile configuration memory accessed during boot and runtime via parallel bus; retains settings across power cycles. Use Value: 100,000 endurance cycles support frequent field updates; 10-year data retention ensures long-term traceability in unattended installations. | Use Scenario: Holding sensor calibration coefficients, patient history flags, and safety-critical setup values in portable diagnostic equipment. IC Role / Device Role / Timing Role: Secure parameter store with software/hardware write protection to prevent corruption during battery swaps or ESD events. Use Value: 100 µA standby current extends battery life; DATA polling enables deterministic firmware update timing without timeout risks. |
| Telecom Base Station Bootloader Parameters | Automotive Body Control Module Settings |
Use Scenario: Storing bootloader configuration, network MAC addresses, and firmware version identifiers in outdoor telecom infrastructure. IC Role / Device Role / Timing Role: Parallel EEPROM interfaced directly to microcontroller's external memory bus; accessed during cold start initialization. Use Value: −40°C to +85°C industrial rating ensures reliability in uncontrolled enclosures; 90 ns access time supports fast boot sequences. | Use Scenario: Retaining user preferences (window position, mirror angle), fault logs, and CAN node configuration in vehicle body control units. IC Role / Device Role / Timing Role: Nonvolatile memory mapped into MCU address space; written infrequently but read on every power-up. Use Value: Hardware VCC-sense protection prevents writes during ignition transients; green (Pb/Halide-free) packaging complies with automotive RoHS requirements. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar EEPROM applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| AT28HC64B-90JI | Same electrical specs and pinout; 32-lead PLCC package instead of 28-lead SOIC | Requires different PCB footprint and reflow profile; suited for through-hole prototyping or legacy board reuse | Select when PLCC socket compatibility or thermal mass requirements dictate larger package |
| AT28HC64B-90TI | Same speed grade and functionality; 28-lead TSOP package with thinner profile (1.2 mm height vs. 2.35 mm SOIC) | Enables higher component density on space-constrained boards; lower thermal mass affects reflow yield | Choose for compact consumer electronics where board thickness is constrained |
Compared with AT28HC64B-90JI and AT28HC64B-90TI, the AT28HC64B-90SI offers optimal balance of surface-mount reliability, thermal performance, and standard SOIC handling - making it preferred for industrial control and medical OEM production where assembly yield and long-term solder joint integrity are critical.
Availability
AT28HC64B-90SI is available at Aetrix Electronics and suitable for industrial PLC configuration storage, medical device calibration data retention, and telecom base station bootloader parameter management requiring stable component supply and long-lifecycle support.
Supply support for AT28HC64B-90SI 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 manufacturer specializing in microcontrollers, nonvolatile memory, and secure authentication ICs.
The AT28HC64B product line delivers high-reliability parallel EEPROMs optimized for embedded systems requiring robust configuration storage, field-upgradable parameters, and deterministic write-cycle feedback - targeting industrial, medical, and communications applications.
FAQ
What is the maximum page write cycle time for AT28HC64B-90SI?
The AT28HC64B-90SI has a maximum page write cycle time of 10 ms under standard conditions. This value is guaranteed across the full industrial temperature range (−40°C to +85°C) and applies to all 1–64 byte page writes. The device does not support the optional 2 ms page write mode (reserved for AT28HC64BF variants), and no configuration setting can reduce this timing for the AT28HC64B-90SI.
How does software data protection work on AT28HC64B-90SI?
Software data protection on AT28HC64B-90SI is enabled by writing three specific bytes (AAh → 1555h, 55h → 0AAAh, A0h → 1555h) in sequence. Once activated, all subsequent writes require repeating this sequence before data. The AT28HC64B-90SI ships with SDP disabled, and the feature remains active across power cycles until explicitly disabled using the 5-byte unlock sequence (AAh/55h/80h/AAh/20h).
Can AT28HC64B-90SI operate with a 3.3 V supply?
No, AT28HC64B-90SI requires a nominal 5 V supply with ±10% tolerance (4.5 V to 5.5 V). It is not 3.3 V compatible. Attempting to power the AT28HC64B-90SI from 3.3 V will result in failure to meet AC timing specifications, unreliable write operations, and potential data corruption due to insufficient VCC for internal charge pumps and logic thresholds.
What is the purpose of the NC pins on AT28HC64B-90SI?
The NC (No Connect) pins on AT28HC64B-90SI - specifically pins 1 and 17 in PLCC variants and designated NC positions in SOIC/TSOP footprints - are physically present but internally unbonded. They must remain unconnected in the circuit. Routing traces to or placing vias on NC pins violates the AT28HC64B-90SI datasheet and may cause signal integrity issues or latch-up due to floating metal structures.
Does AT28HC64B-90SI support chip erase functionality?
Yes, AT28HC64B-90SI supports chip erase using a dedicated waveform: applying 12.0 V ±0.5 V to A9 while holding CE low, OE high, and WE low for ≥10 ms. This erases the entire 64 Kbit array to FFh. Chip erase is distinct from page/byte writes and requires external 12 V generation - not supported by standard 5 V-only systems. The AT28HC64B-90SI datasheet specifies exact timing and voltage tolerances for safe execution.
AT28HC64B-90SI Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Microchip Technology
- Series:
- -
- Package/Case:
- 28-SOIC (0.295", 7.50mm Width)
- 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:
- 28-SOIC
AT28HC64B-90SI FAQ
1.How can I place an order for AT28HC64B-90SI through Aetrix?
Please submit a Request for Quotation (RFQ) for AT28HC64B-90SI 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-90SI reliable?
The price and inventory of AT28HC64B-90SI are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for AT28HC64B-90SI is usually 5 days.
3.What payment methods are accepted for AT28HC64B-90SI?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for AT28HC64B-90SI transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for AT28HC64B-90SI?
AT28HC64B-90SI orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your AT28HC64B-90SI 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-90SI?
For technical support, including AT28HC64B-90SI datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your AT28HC64B-90SI requirements.
6.How does Aetrix verify that AT28HC64B-90SI is sourced from the original manufacturer or authorized distributors?
All AT28HC64B-90SI 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-90SI meets industry standards.
7.What is the process for return or replacement of AT28HC64B-90SI?
All AT28HC64B-90SI units undergo pre-shipment inspection (PSI). If there is an issue with AT28HC64B-90SI, 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-90SI part is unused and in its original packaging.
Return procedure for AT28HC64B-90SI:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
AT28HC64B-90SI Tags
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