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Microchip Technology AT28HC256F-12PI
- Part No.:
- AT28HC256F-12PI
- Manufacturer:
- Microchip Technology
- Category:
- Memory
- Package:
- 28-DIP (0.600", 15.24mm)
- Datasheet:
-
AT28HC256F-12PI.pdf
- Description:
- IC EEPROM 256KBIT PARALLEL 28DIP
- Quantity:
- Payment:
- Shipping:
Inventory:1,505
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Product details
Overview
AT28HC256F-12PI from Microchip Technology (formerly Atmel) is a 256 Kbit (32K × 8) parallel EEPROM IC used for nonvolatile program/data storage in embedded control and instrumentation systems. It delivers 70 ns read access time, supports 3 ms page write cycles, operates on single 5V ±10% supply, and features hardware/software data protection. It is commonly deployed in industrial PLCs for firmware retention and configuration backup.
For engineers reviewing the AT28HC256F-12PI datasheet, AT28HC256F-12PI pinout, AT28HC256F-12PI application, or AT28HC256F-12PI equivalent, key selection considerations include its JEDEC-standard 28-pin SOIC package, 3 ms fast write option, industrial temperature range (–40°C to +85°C), and DATA Polling/Toggle Bit write completion detection.
Technical Context
The AT28HC256F-12PI implements a CMOS-based parallel EEPROM architecture with internal 64-byte page latches and an autonomous control timer for self-timed write operations. Its dual-line chip enable (CE) and output enable (OE) logic enables bus contention avoidance in shared-memory systems.
Write operation support includes byte-write, 1–64-byte page-write, software chip erase, and optional device identification EEPROM (64 bytes at 7FC0H–7FFFH). Data integrity is enforced via VCC sense, noise filtering, and software data protection (SDP) with enable/disable command sequences.
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 - defines minimum clock-to-data latency in SRAM-compatible read cycles |
| Page Write Cycle Time | 3 ms maximum - enables rapid bulk updates without external timing control |
| Endurance | 10,000 write/erase cycles - specifies guaranteed reprogrammability before wear-out |
| Data Retention | 10 years at 85°C - ensures long-term validity of stored configuration or calibration data |
| Supply Voltage | 5V ±10% - compatible with legacy 5V TTL/CMOS logic rails without level shifting |
| Operating Temperature | –40°C to +85°C - qualified for industrial-grade environmental stress |
Pinout & Package
AT28HC256F-12PI is supplied in a 28-lead, 0.300" wide plastic gull-wing small outline (SOIC) package per JEDEC MS-013, with 1.27 mm pitch and standard pin 1 marking.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| A0–A14 | Address Inputs | 15-bit address bus selecting one of 32,768 memory locations |
| I/O0–I/O7 | Bidirectional Data Bus | 8-bit parallel interface for read/write data transfer; high-impedance when disabled |
| CE | Chip Enable | Active-low global select; disables all internal operations when high |
| OE | Output Enable | Active-low output gate; controls data bus drive during read only |
| WE | Write Enable | Active-low write strobe; initiates byte or page write on falling edge |
| VCC | Power Supply | +5V ±10% main supply; powers core logic and I/O buffers |
| GND | Ground Reference | Signal and power return path; must be low-impedance for noise immunity |
Key Features
| Feature | Design Value |
|---|---|
| JEDEC Byte-wide Pinout | Ensures drop-in compatibility with industry-standard EPROM/EEPROM sockets and PCB footprints |
| DATA Polling & Toggle Bit | Hardware-supported write completion detection eliminates need for fixed delay timers in firmware |
| 64-byte Page Register | Allows burst loading of up to 64 bytes before automatic internal programming, reducing host CPU overhead |
| Software Data Protection (SDP) | User-configurable lock mechanism prevents accidental writes without issuing 3-byte unlock sequence |
| VCC Sense & Noise Filtering | Prevents spurious writes during power ramp-up or EMI events by rejecting sub-3.8V supplies and <15 ns glitches |
Applications
| Industrial PLC Firmware Storage | Medical Device Calibration Data Backup |
|---|---|
Use Scenario: Storing boot firmware and runtime configuration in programmable logic controllers operating in factory-floor environments with voltage fluctuations and thermal cycling. IC Role / Device Role / Timing Role: Nonvolatile code and parameter storage with SRAM-like read interface and deterministic 3 ms page write for field updates. Use Value: Eliminates need for external write timing circuitry; 10-year data retention ensures calibration stability across equipment service life. | Use Scenario: Preserving sensor calibration coefficients and safety-critical settings in portable diagnostic instruments requiring regulatory traceability. IC Role / Device Role / Timing Role: Secure, tamper-resistant configuration memory with software data protection and 64-byte device ID area for serialization. Use Value: SDP prevents unintended overwrites during firmware upgrades; industrial temp rating supports sterilization cycle exposure. |
| Avionics Control Module Boot Memory | Test Equipment Configuration EEPROM |
Use Scenario: Holding bootloader code and flight-critical configuration tables in airborne control units where radiation tolerance and long-term reliability are mandatory. IC Role / Device Role / Timing Role: Radiation-hardened-adjacent nonvolatile memory with 10K endurance and 120 ns read timing for deterministic startup sequencing. Use Value: Single 5V supply simplifies power design; CE/OE dual-control logic avoids bus conflicts during system reset transitions. | Use Scenario: Storing instrument-specific test profiles, calibration offsets, and user preferences in automated test systems subject to frequent reconfiguration. IC Role / Device Role / Timing Role: Field-upgradable parameter store supporting rapid 3 ms page writes and DATA Polling for tight production test cycle times. Use Value: Fast page write reduces test station dwell time; JEDEC pinout allows reuse of existing socket designs across product generations. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar parallel EEPROM applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| AT28C256-12PI | Standard endurance (10K cycles); 10 ms page write time vs. AT28HC256F-12PI's 3 ms | Suitable for infrequent configuration updates where write speed is not critical | Select when cost sensitivity outweighs need for fast field updates |
| MN63C256B-12PI | Same 256K × 8 organization and SOIC-28 package; 100K endurance option available | Offers extended endurance variant but lacks software data protection feature | Choose when higher write-cycle lifetime is required and SDP is not mandated |
Compared with AT28HC256F-12PI, AT28C256-12PI trades faster write capability for lower cost, while MN63C256B-12PI provides higher endurance but omits software write protection-making AT28HC256F-12PI optimal for industrial systems requiring both speed and secure update control.
Availability
AT28HC256F-12PI is available at Aetrix Electronics and suitable for industrial PLCs, medical diagnostics equipment, avionics control modules, and automated test systems requiring stable component supply across extended production lifecycles.
Supply support for AT28HC256F-12PI 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 legacy AT28HC256 family, delivering high-reliability nonvolatile memory solutions for industrial and aerospace markets.
The AT28HC256 product line was designed for robust, pin-compatible replacement of UV-erasable EPROMs in legacy 5V systems-emphasizing ease of migration, JEDEC compliance, and long-term data integrity under harsh conditions.
FAQ
What is the maximum write cycle time for AT28HC256F-12PI?
The AT28HC256F-12PI has a maximum page write cycle time of 3 ms, enabled by its "F" fast-write option. This is confirmed in Section 16 of the datasheet and distinguishes it from standard AT28HC256 variants (e.g., AT28HC256-12PI) which require up to 10 ms. The 3 ms specification applies to all 1–64-byte page writes within the same memory page (A6–A14 constant).
Does AT28HC256F-12PI support software data protection?
Yes, AT28HC256F-12PI supports Software Data Protection (SDP) via a documented three-byte command sequence (AAh → 55h → A0h to address 5555h/2AAAh/5555h). Once enabled, all subsequent writes require reissuing the unlock sequence. SDP is shipped disabled and remains active across power cycles, providing persistent write security for critical configuration data stored in AT28HC256F-12PI.
What package type is used for AT28HC256F-12PI?
AT28HC256F-12PI uses a 28-lead, 0.300" wide plastic gull-wing small outline (SOIC) package, designated as "28S" in Atmel's ordering nomenclature. This package conforms to JEDEC standard MS-013, features 1.27 mm lead pitch, and is RoHS-compliant with green (Pb/halide-free) construction.
How is write completion detected on AT28HC256F-12PI?
AT28HC256F-12PI supports two hardware-assisted write completion detection methods: DATA Polling (monitoring complement of last written byte on I/O7) and Toggle Bit (observing toggling state of I/O6). Both methods allow real-time polling without fixed delays; the device asserts valid data on all outputs once the internal 3 ms write timer completes, enabling immediate subsequent access to AT28HC256F-12PI.
What temperature range is specified for AT28HC256F-12PI?
AT28HC256F-12PI is rated for industrial temperature operation from –40°C to +85°C, as indicated by the "I" suffix in its part number. This qualification is verified per Section 5 of the datasheet and includes full functionality for read, write, and standby modes across the entire range, making it suitable for deployment in demanding environments such as factory automation and outdoor instrumentation where AT28HC256F-12PI operates reliably.
AT28HC256F-12PI Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Microchip Technology
- Series:
- -
- Package/Case:
- 28-DIP (0.600", 15.24mm)
- 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:
- Through Hole
- Supplier Device Package:
- 28-PDIP
AT28HC256F-12PI FAQ
1.How can I place an order for AT28HC256F-12PI through Aetrix?
Please submit a Request for Quotation (RFQ) for AT28HC256F-12PI 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-12PI reliable?
The price and inventory of AT28HC256F-12PI are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for AT28HC256F-12PI is usually 5 days.
3.What payment methods are accepted for AT28HC256F-12PI?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for AT28HC256F-12PI transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for AT28HC256F-12PI?
AT28HC256F-12PI orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your AT28HC256F-12PI 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-12PI?
For technical support, including AT28HC256F-12PI datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your AT28HC256F-12PI requirements.
6.How does Aetrix verify that AT28HC256F-12PI is sourced from the original manufacturer or authorized distributors?
All AT28HC256F-12PI 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-12PI meets industry standards.
7.What is the process for return or replacement of AT28HC256F-12PI?
All AT28HC256F-12PI units undergo pre-shipment inspection (PSI). If there is an issue with AT28HC256F-12PI, 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-12PI part is unused and in its original packaging.
Return procedure for AT28HC256F-12PI:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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