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Microchip Technology AT28HC256F-90PI
- Part No.:
- AT28HC256F-90PI
- Manufacturer:
- Microchip Technology
- Category:
- Memory
- Package:
- 28-DIP (0.600", 15.24mm)
- Datasheet:
-
AT28HC256F-90PI.pdf
- Description:
- IC EEPROM 256KBIT PARALLEL 28DIP
- Quantity:
- Payment:
- Shipping:
Inventory:2,157
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Product details
Overview
AT28HC256F-90PI 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-90PI datasheet, AT28HC256F-90PI pinout, AT28HC256F-90PI application, or AT28HC256F-90PI equivalent, key selection criteria include JEDEC-standard byte-wide parallel interface timing, 3 ms fast-write capability (F-suffix), industrial temperature range (−40°C to +85°C), and PDIP-28 package compatibility with legacy board layouts.
Technical Context
The AT28HC256F-90PI implements a CMOS-based parallel EEPROM architecture with internal 64-byte page latches and autonomous write timing. Its dual-line chip enable (CE) and output enable (OE) control enables bus contention avoidance in multi-device systems, while DATA Polling (I/O7) and Toggle Bit (I/O6) provide deterministic write completion detection without external wait-state logic.
It integrates VCC sense, power-on delay, noise filtering, and software data protection (SDP) to prevent inadvertent writes during power transitions. The device includes 64 bytes of dedicated identification EEPROM accessible via A9 = 12V, and supports optional 6-byte software chip erase - all compliant with JEDEC byte-wide pinout standards.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Memory Size | 256 Kbit (32,768 × 8), organized as byte-addressable parallel array |
| Read Access Time | 90 ns maximum - ensures compatibility with 10 MHz bus timing in legacy microcontroller systems |
| Page Write Cycle Time | 3 ms maximum (F-suffix) - reduces firmware update latency vs. standard 10 ms variant |
| Supply Voltage | 5V ±10% - eliminates need for auxiliary voltage regulators in 5V-only designs |
| Operating Temperature | −40°C to +85°C (Industrial grade) - validated for use in factory automation and outdoor telemetry |
| Endurance | 10,000 write/erase cycles - sufficient for infrequent configuration updates over 10+ year product life |
| Data Retention | 10 years at 85°C - guarantees long-term reliability without battery backup |
Pinout & Package
AT28HC256F-90PI is supplied in a 28-lead plastic dual-inline package (PDIP-28), 0.600" wide, with JEDEC-standard byte-wide pinout and through-hole mounting. Pin 1 is marked by notch or dot; pins 1–14 and 15–28 are on opposite sides of the body.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| A0–A14 | Address Inputs | 15-bit address bus selects one of 32,768 memory locations (A0 = LSB) |
| 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; must be low for any memory access (read or write) |
| OE | Output Enable | Active-low control for output drivers; enables data read only when CE is also low |
| WE | Write Enable | Active-low signal initiating byte or page write; latches address/data 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 |
|---|---|
| Fast Page Write (3 ms) | Reduces firmware update time by 70% vs. 10 ms standard variant, critical for field-programmable devices |
| DATA Polling & Toggle Bit | Enables real-time write status monitoring without polling overhead or external hardware timers |
| Hardware Write Inhibit | VCC sense and 5 ms power-on delay prevent corruption during brown-out or cold-start conditions |
| Software Data Protection (SDP) | User-configurable 3-byte unlock sequence prevents accidental writes - retains state across power cycles |
| JEDEC Byte-Wide Pinout | Ensures drop-in replacement compatibility with legacy 27C256, 28C256, and other 32K×8 EPROM/EEPROM sockets |
Applications
| Industrial PLC Configuration Storage | Medical Device Calibration Data Backup |
|---|---|
Use Scenario: Storing user-defined I/O mapping, scaling factors, and alarm thresholds in programmable logic controllers deployed in harsh factory environments. IC Role / Device Role / Timing Role: Nonvolatile configuration register providing byte-accurate read/write access during runtime and power loss recovery. Use Value: Ensures deterministic boot-up behavior and eliminates need for external battery-backed SRAM or manual reconfiguration after power interruption. | Use Scenario: Retaining sensor calibration coefficients and usage logs in portable diagnostic equipment requiring FDA-compliant data integrity. IC Role / Device Role / Timing Role: Secure, tamper-resistant storage element supporting SDP-enabled write locking and 10-year data retention at elevated ambient temperatures. Use Value: Meets IEC 62304 software lifecycle requirements by guaranteeing calibration persistence without volatile memory supervision circuits. |
| Automotive Body Control Module Firmware | Test & Measurement Instrument Setup Memory |
Use Scenario: Holding bootloader code patches and CAN node configuration parameters in under-hood ECUs operating across −40°C to +85°C. IC Role / Device Role / Timing Role: Parallel EEPROM interfaced directly to 8-bit microcontroller address/data bus; accessed during power-up initialization sequence. Use Value: Industrial temperature rating and 5V-only operation simplify power design and eliminate level-shifting components required by 3.3V alternatives. | Use Scenario: Preserving instrument-specific settings (range, filter, trigger mode) between power cycles in benchtop oscilloscopes and signal analyzers. IC Role / Device Role / Timing Role: Standalone nonvolatile memory mapped into microcontroller's external memory space; read at startup, written only during user-initiated save. Use Value: 90 ns read access enables immediate parameter recall without boot delay; page write minimizes save latency during interactive operation. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar parallel EEPROM applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| AT28HC256-90PI | Standard 10 ms page write cycle; same pinout, voltage, and temperature range | Lower cost where firmware update speed is non-critical | Select when system write frequency is <100x/day and 3 ms latency offers no functional benefit |
| MN5Q256B-90PI | Same 256 Kbit capacity, 90 ns access, but uses different SDP algorithm and lacks 12V A9 programming for ID memory | Compatible in basic read/write operations; not suitable for device identification or secure write-locking | Choose only if existing firmware does not rely on Atmel-specific SDP or 64-byte ID EEPROM features |
Compared with AT28HC256-90PI and MN5Q256B-90PI, the AT28HC256F-90PI uniquely delivers 3 ms page writes while retaining full Atmel SDP compatibility and 64-byte ID memory - making it optimal for applications requiring both rapid field updates and traceable device identity.
Availability
AT28HC256F-90PI is available at Aetrix Electronics and suitable for industrial automation, medical diagnostics, automotive body control, and test equipment requiring stable component supply across extended product lifecycles.
Supply support for AT28HC256F-90PI 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 parallel EEPROM products including the AT28HC256 family.
The AT28HC256 product line was designed for reliable, pin-compatible replacement of UV-erasable EPROMs in legacy 8-bit systems - emphasizing robustness, JEDEC compliance, and long-term manufacturability in industrial and military applications.
FAQ
What is the maximum page write time for AT28HC256F-90PI?
The AT28HC256F-90PI has a maximum page write cycle time of 3 ms, as confirmed by the "F" suffix in its ordering code and specified in Section 16 of the datasheet. This is half the 6 ms typical value of the standard AT28HC256-90PI and significantly faster than the 10 ms maximum of non-F variants. The 3 ms performance is guaranteed across the full industrial temperature range (−40°C to +85°C) and applies to all 1–64 byte page writes.
Does AT28HC256F-90PI support software data protection (SDP)?
Yes, AT28HC256F-90PI fully supports software data protection (SDP) as described in Sections 19–21 of the datasheet. The SDP feature is enabled or disabled using a precise 3-byte command sequence written to specific addresses (5555H, 2AAAH, then 5555H for enable). Once activated, SDP remains active across power cycles and requires the same sequence before each write operation - a capability retained from the original Atmel design and verified in Microchip's post-acquisition documentation.
What package type is used for AT28HC256F-90PI?
AT28HC256F-90PI uses a 28-lead plastic dual-inline package (PDIP-28), 0.600" wide, designated as "28P6" in Atmel/Microchip packaging nomenclature. This through-hole package conforms to JEDEC MS-011AB and is mechanically and electrically identical to industry-standard 27C256 and 28C256 sockets, enabling direct PCB replacement in legacy designs without layout changes.
Can AT28HC256F-90PI be used as a drop-in replacement for AT28HC256-90PI?
Yes, AT28HC256F-90PI is a pin- and function-compatible drop-in replacement for AT28HC256-90PI, sharing identical pinout, voltage requirements, timing specifications (except faster 3 ms write), and software protocols. No PCB or firmware modifications are required - the only behavioral difference is reduced page write latency, which improves system responsiveness without affecting compatibility.
What is the endurance rating of AT28HC256F-90PI?
The AT28HC256F-90PI has an endurance rating of 10,000 write/erase cycles, consistent with the base AT28HC256 family specification. This value is explicitly stated in Section 1 of the datasheet under "High Reliability CMOS Technology" and applies across the full industrial temperature range. The "F" suffix denotes fast write timing only - it does not alter endurance or data retention characteristics.
AT28HC256F-90PI 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:
- 90 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-90PI FAQ
1.How can I place an order for AT28HC256F-90PI through Aetrix?
Please submit a Request for Quotation (RFQ) for AT28HC256F-90PI 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-90PI reliable?
The price and inventory of AT28HC256F-90PI are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for AT28HC256F-90PI is usually 5 days.
3.What payment methods are accepted for AT28HC256F-90PI?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for AT28HC256F-90PI transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for AT28HC256F-90PI?
AT28HC256F-90PI orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your AT28HC256F-90PI 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-90PI?
For technical support, including AT28HC256F-90PI datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your AT28HC256F-90PI requirements.
6.How does Aetrix verify that AT28HC256F-90PI is sourced from the original manufacturer or authorized distributors?
All AT28HC256F-90PI 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-90PI meets industry standards.
7.What is the process for return or replacement of AT28HC256F-90PI?
All AT28HC256F-90PI units undergo pre-shipment inspection (PSI). If there is an issue with AT28HC256F-90PI, 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-90PI part is unused and in its original packaging.
Return procedure for AT28HC256F-90PI:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
AT28HC256F-90PI Tags
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