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Microchip Technology AT28HC256F-12JI
- Part No.:
- AT28HC256F-12JI
- Manufacturer:
- Microchip Technology
- Category:
- Memory
- Package:
- 32-LCC (J-Lead)
- Datasheet:
-
AT28HC256F-12JI.pdf
- Description:
- IC EEPROM 256KBIT PAR 32PLCC
- Quantity:
- Payment:
- Shipping:
Inventory:3,468
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Product details
Overview
AT28HC256F-12JI from Microchip Technology (formerly Atmel) is a 256 Kbit (32K × 8) parallel EEPROM with JEDEC-standard byte-wide pinout, 120 ns read access time, 3 ms page write cycle, and industrial temperature range (–40°C to +85°C). It operates from a single 5V ±10% supply and supports hardware/software data protection for embedded control and firmware storage applications.
For engineers reviewing the AT28HC256F-12JI datasheet, AT28HC256F-12JI pinout, AT28HC256F-12JI application, or AT28HC256F-12JI equivalent, key selection criteria include verified 3 ms fast page write timing, 10⁵ write endurance, DATA Polling and Toggle Bit write completion detection, and TSOP-28 industrial-grade packaging.
Technical Context
The AT28HC256F-12JI implements a CMOS-based parallel EEPROM architecture with internal 64-byte page latching and autonomous internal control timer for self-timed writes. Its dual-line chip enable (CE) and output enable (OE) logic enables bus contention avoidance in microcontroller systems without external glue logic.
It features VCC sense and power-on delay hardware write inhibition, plus software data protection (SDP) via three-byte command sequence. The device includes 64 bytes of dedicated identification EEPROM accessible at 7FC0H–7FFFH using A9 = 12V.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Memory Size | 256 Kbit (32,768 × 8), organized as byte-addressable nonvolatile storage |
| Read Access Time | 120 ns maximum - determines minimum CPU wait-state requirement for direct SRAM-style interface |
| Page Write Cycle Time | 3 ms typical - enables high-throughput firmware updates with up to 64 bytes per write operation |
| Endurance | 100,000 write/erase cycles - validated for long-life field-programmable configuration storage |
| Data Retention | 10 years at +85°C - ensures reliability in industrial environments without refresh |
| Supply Voltage | 5V ±10% - compatible with legacy 5V TTL/CMOS system rails without level shifting |
| Operating Temperature | –40°C to +85°C - qualified for industrial control, instrumentation, and automotive under-hood modules |
Pinout & Package
AT28HC256F-12JI is supplied in a 28-lead Plastic Thin Small Outline Package (TSOP, Type I, 8 mm × 13.4 mm), JEDEC MO-183 compliant, with gull-wing leads and pin 1 identifier notch. Pinout follows JEDEC-approved byte-wide standard.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| A0–A14 | Address Inputs | 15-bit address bus supporting full 32K-word addressing; A6–A14 define page boundaries for 64-byte writes |
| I/O0–I/O7 | Bi-directional Data Bus | CMOS/TTL-compatible 8-bit data path; supports true read/write without direction control |
| CE | Chip Enable | Active-low device select; must be low with OE low and WE high for read access |
| OE | Output Enable | Active-low output gate; used with CE to prevent bus contention during multi-device sharing |
| WE | Write Enable | Active-low write strobe; falling edge latches address/data; initiates byte or page programming |
| VCC | Power Supply | +5V ±10% supply; internal VCC sense disables writes below ~3.8V |
| GND | Ground Reference | Signal and power return; decoupling capacitor required within 1 cm of VCC/GND pins |
Key Features
| Feature | Design Value |
|---|---|
| Fast Page Write (3 ms) | Reduces firmware update latency by >66% vs. standard 10 ms variant, enabling faster field reprogramming |
| DATA Polling & Toggle Bit | Hardware-supported write completion detection on I/O7 and I/O6 eliminates need for fixed delays or external polling timers |
| Software Data Protection (SDP) | User-configurable 3-byte command lock prevents accidental writes during power transitions or debug sessions |
| 64-byte Identification EEPROM | Dedicated memory region (7FC0H–7FFFH) accessible with 12V on A9 for unique device serialization or calibration storage |
| Industrial Temperature Range | Validated operation from –40°C to +85°C ensures reliability in programmable logic controllers and motor drives |
Applications
| Industrial PLC Configuration Storage | Firmware Bootloader Storage |
|---|---|
Use Scenario: Storing user-defined ladder logic parameters and I/O mapping tables in programmable logic controllers subject to frequent power cycling. IC Role / Device Role / Timing Role: Nonvolatile configuration register bank accessed via 8051 or ARM Cortex-M3 parallel bus during boot and runtime reconfiguration. Use Value: 3 ms page write enables rapid parameter save after operator input; 10⁵ endurance supports >10 years of daily configuration changes. | Use Scenario: Holding bootloader code and secure boot keys in embedded systems requiring field-upgradable firmware with rollback capability. IC Role / Device Role / Timing Role: Parallel-mapped boot memory mapped at reset vector; accessed before main application initialization. Use Value: 120 ns read access meets tight timing budgets for zero-wait-state boot execution; SDP prevents corruption during partial power loss. |
| Metering Calibration Data Archive | Medical Device Setup Profile Storage |
Use Scenario: Archiving factory-calibrated sensor coefficients and linearity correction tables in utility smart meters operating unattended for 15+ years. IC Role / Device Role / Timing Role: High-reliability data archive accessed only during calibration or firmware upgrade; isolated from main application bus. Use Value: 10-year data retention at +85°C ensures accuracy compliance over full product lifecycle without battery backup. | Use Scenario: Storing clinician-configured therapy profiles and safety limits in portable infusion pumps with strict regulatory traceability requirements. IC Role / Device Role / Timing Role: Secure, write-protected parameter store accessed via microcontroller SPI-to-parallel bridge during setup mode. Use Value: Hardware VCC-sense + SDP enforces write inhibition during brown-out events, satisfying IEC 62304 Class C safety requirements. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar parallel EEPROM applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| AT28HC256-12JI | Standard 10 ms page write cycle; same pinout, package, and voltage specs | Lower write throughput; suitable where update frequency is infrequent | Select when cost sensitivity outweighs write speed requirement and 10 ms latency is acceptable |
| MX28LV256A-12J1I | Macronix equivalent with 120 ns access, 3 ms write, and identical TSOP-28 industrial packaging | Same functional behavior and timing; requires validation of SDP command compatibility | Drop-in alternative with second-source availability; verify SDP enable/disable sequence match in system firmware |
Compared with AT28HC256-12JI, the AT28HC256F-12JI delivers 3× faster page writes for time-critical updates, while MX28LV256A-12J1I offers a validated pin- and function-compatible second source with identical industrial qualification.
Availability
AT28HC256F-12JI is available at Aetrix Electronics and suitable for industrial automation, medical device manufacturing, and energy metering applications requiring stable component supply across extended product lifecycles.
Supply support for AT28HC256F-12JI 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 the AT28HC256 family, including long-term supply commitment and technical documentation.
The AT28HC256 product line was designed for reliable, low-power, parallel-interface nonvolatile storage in resource-constrained embedded systems where SRAM-like access and field programmability are essential.
FAQ
What is the guaranteed page write cycle time for AT28HC256F-12JI?
The AT28HC256F-12JI guarantees a maximum page write cycle time of 3 ms, confirmed in Section 16 of the datasheet. This is the defining "F" option feature distinguishing it from the standard 10 ms variant. The 3 ms timing applies to all 1–64 byte page writes within the same 64-byte boundary defined by A6–A14, and is validated across the full industrial temperature range.
Does AT28HC256F-12JI support both DATA Polling and Toggle Bit for write completion detection?
Yes, AT28HC256F-12JI supports both methods. DATA Polling monitors complemented data on I/O7 during write cycles, while Toggle Bit observes toggling on I/O6 until completion. Both are fully functional and documented in Sections 4.4 and 4.5. Either method can be implemented in host firmware to eliminate fixed delays and improve system responsiveness during writes.
What package type is used for AT28HC256F-12JI?
AT28HC256F-12JI uses a 28-lead Plastic Thin Small Outline Package (TSOP, Type I), designated as package code "28T" in Microchip's ordering information. Its dimensions are 8 mm × 13.4 mm, with gull-wing leads and JEDEC MO-183 compliance. Pin 1 is marked by a notch on the top surface.
How does software data protection (SDP) work on AT28HC256F-12JI?
AT28HC256F-12JI implements SDP via a three-byte command sequence written to specific addresses (5555H, 2AAAH, then 5555H with data A0H to enable). Once enabled, all subsequent writes require repeating this sequence before data. SDP remains active through power cycles and is disabled only by a separate five-byte disable sequence. The AT28HC256F-12JI ships with SDP disabled.
Is the 64-byte identification EEPROM in AT28HC256F-12JI accessible under normal 5V operation?
No. The 64-byte identification EEPROM (addresses 7FC0H–7FFFH) requires A9 to be raised to 12.0V ±0.5V for access, as specified in Section 4.7. Under standard 5V operation, those addresses behave as regular memory. This high-voltage requirement prevents accidental writes and ensures isolation from normal firmware operations.
AT28HC256F-12JI 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:
- 256Kbit
- Memory Organization:
- 32K x 8
- Memory Interface:
- Parallel
- Clock Frequency:
- -
- Write Cycle Time - Word, Page:
- 3ms
- Access Time:
- 120 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)
AT28HC256F-12JI FAQ
1.How can I place an order for AT28HC256F-12JI through Aetrix?
Please submit a Request for Quotation (RFQ) for AT28HC256F-12JI 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 AT28HC256F-12JI reliable?
The price and inventory of AT28HC256F-12JI are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for AT28HC256F-12JI is usually 5 days.
3.What payment methods are accepted for AT28HC256F-12JI?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for AT28HC256F-12JI transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for AT28HC256F-12JI?
AT28HC256F-12JI orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your AT28HC256F-12JI 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 AT28HC256F-12JI?
For technical support, including AT28HC256F-12JI datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your AT28HC256F-12JI requirements.
6.How does Aetrix verify that AT28HC256F-12JI is sourced from the original manufacturer or authorized distributors?
All AT28HC256F-12JI 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 AT28HC256F-12JI meets industry standards.
7.What is the process for return or replacement of AT28HC256F-12JI?
All AT28HC256F-12JI units undergo pre-shipment inspection (PSI). If there is an issue with AT28HC256F-12JI, 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 AT28HC256F-12JI part is unused and in its original packaging.
Return procedure for AT28HC256F-12JI:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
AT28HC256F-12JI Tags
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AT24C02C-XHM-T
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AT21CS01-STUM10-T
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AT24CS02-SSHM-T
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93LC46BT-I/OT
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24LC01BT-I/SN
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