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Microchip Technology AT28C256F-15SU-T
- Part No.:
- AT28C256F-15SU-T
- Manufacturer:
- Microchip Technology
- Category:
- Memory
- Package:
- 28-SOIC (0.295", 7.50mm Width)
- Datasheet:
-
AT28C256F-15SU-T.pdf
- Description:
- IC EEPROM 256KBIT PAR 28SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:4,552
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Product details
Overview
AT28C256F-15SU-T from Microchip Technology is an industrial-grade 256-Kbit paged parallel EEPROM organized as 32,768 × 8, featuring 150 ns read access time, 3 ms maximum page write cycle time, single 5V ±10% supply operation, and JEDEC-approved byte-wide pinout. It serves as nonvolatile program/data storage in embedded controllers, industrial PLCs, and legacy system BIOS modules where byte- or page-level reprogrammability is required without external high-voltage circuitry.
For engineers reviewing the AT28C256F-15SU-T datasheet, AT28C256F-15SU-T pinout, AT28C256F-15SU-T application, or AT28C256F-15SU-T equivalent, key selection criteria include its fast 3 ms page write capability (vs. 10 ms standard), CMOS/TTL-compatible I/O, hardware/software data protection, DATA Polling and Toggle Bit write completion detection, and industrial temperature range (-40°C to +85°C) compliance.
Technical Context
The AT28C256F-15SU-T implements a paged architecture with a 64-byte internal page register, enabling simultaneous latching of up to 64 bytes for internal self-timed programming. Its dual-line chip enable (CE) and output enable (OE) control allows bus contention avoidance in shared-memory systems.
Write operations support three modes: byte write, page write (1–64 bytes within same A6–A14 page boundary), and optional software-enabled chip erase. End-of-write detection is implemented via DATA Polling on I/O7 or Toggle Bit behavior on I/O6 - both usable at any point during tWC without halting host operation.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Memory Density | 256 Kbit (32,768 × 8) - supports full firmware image or configuration table storage in legacy 8-bit microcontroller systems. |
| Read Access Time | 150 ns - enables direct replacement of SRAM in wait-state-free 5 MHz bus interfaces. |
| Page Write Cycle Time | 3 ms max - 3× faster than standard AT28C256-15 variants, reducing firmware update latency in field-programmable devices. |
| Supply Voltage | 5V ±10% - operates directly from standard logic rail without auxiliary voltage regulators. |
| Operating Temperature | -40°C to +85°C - qualified for industrial control cabinets, motor drives, and outdoor instrumentation enclosures. |
| Endurance | 10,000 write/erase cycles - sufficient for infrequent calibration data logging or parameter tuning in maintenance-critical equipment. |
| Data Retention | 10 years - ensures long-term validity of stored device identifiers, calibration coefficients, or security keys without refresh. |
Pinout & Package
AT28C256F-15SU-T is supplied in a 28-lead SOIC package (SOIC-28, 300 mil width) with JEDEC-standard byte-wide pinout and no internal connection to pins 1 and 26 (NC). Pin functions are electrically identical across PDIP, PLCC, and SOIC variants per Microchip DS20006386B.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| A0–A14 | Address Inputs | 15-bit address bus supporting full 32K-word addressing; A6–A14 define 64-byte page boundaries for page write mode. |
| I/O0–I/O7 | Bidirectional Data Bus | CMOS/TTL-compatible 8-bit data path; I/O7 used for DATA Polling, I/O6 for Toggle Bit status reporting. |
| CE | Chip Enable | Active-low global enable; must be low for read/write access; high-Z output when asserted high. |
| OE | Output Enable | Active-low output gate; controls data bus drive without affecting internal state - critical for bus arbitration. |
| WE | Write Enable | Active-low write strobe; falling edge latches address/data; initiates byte or page programming sequence. |
| VCC / GND | Power Supply | Single 5V supply with ≤200 µA standby current - enables low-power sleep modes in battery-backed systems. |
| NC (Pins 1, 26) | No Connect | Unbonded die pads; must remain unconnected per Microchip specification to prevent latch-up or ESD damage. |
Key Features
| Feature | Design Value |
|---|---|
| Fast 3 ms Page Write | Reduces firmware patch time by 67% vs. 10 ms standard variant - critical for time-sensitive field updates in medical or test equipment. |
| DATA Polling & Toggle Bit | Enables real-time write status monitoring without polling overhead or dedicated interrupt lines - simplifies host firmware design. |
| Hardware + Software Data Protection | VCC sense, power-on delay, and 3-byte SDP command sequence prevent accidental writes during brown-out or reset conditions. |
| 64-byte Device ID Area | Separate memory region (7FC0H–7FFFH) accessible at 12V on A9 - supports unique serialization, calibration traceability, or anti-counterfeiting. |
| JEDEC Byte-Wide Pinout | Direct drop-in compatibility with legacy 27C256 EPROM and 62256 SRAM footprints - eliminates PCB redesign in retrofit applications. |
Applications
| Industrial PLC Configuration Storage | Legacy BIOS/Bootloader Memory |
|---|---|
Use Scenario: Storing ladder logic parameters, I/O mapping tables, and alarm thresholds in programmable logic controllers deployed in factory automation environments. IC Role / Device Role / Timing Role: Nonvolatile configuration store accessed via 8-bit parallel bus; provides deterministic 150 ns read timing for real-time scan-cycle execution. Use Value: Enables field-upgradable logic configurations without requiring external programming hardware or system downtime. | Use Scenario: Holding boot code, hardware initialization routines, and POST diagnostics in x86-based industrial PCs and embedded SBCs using ISA or LPC bus interfaces. IC Role / Device Role / Timing Role: Primary boot ROM replacement with SRAM-like read interface; supports direct execution from address 00000h in 80x86 real-mode systems. Use Value: Eliminates need for UV-erasable EPROM sockets and programmers - reduces BOM cost and improves manufacturing yield. |
| Calibration Data Logger | Motor Drive Parameter Storage |
Use Scenario: Recording sensor offset/gain coefficients, thermal drift compensation values, and linearity correction tables during factory calibration of precision measurement instruments. IC Role / Device Role / Timing Role: Secure, write-protected nonvolatile memory accessed only during calibration mode; uses software data protection to prevent runtime corruption. Use Value: Ensures metrological traceability and repeatability across product lifetime without requiring recalibration tools at end-user site. | Use Scenario: Storing torque/speed profiles, PID loop gains, and safety interlock settings in variable-frequency drives used in HVAC and pumping systems. IC Role / Device Role / Timing Role: Runtime-configurable parameter bank accessed during drive startup and fault recovery sequences; supports 3 ms page writes for rapid profile switching. Use Value: Allows OEMs to deploy single hardware SKU across multiple motor types - reducing inventory complexity and service spare parts count. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar paged parallel EEPROM applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| AT28C256-15SU | 10 ms page write cycle; same pinout, voltage, and temperature rating. | Lacks fast 3 ms write performance - unsuitable for time-critical firmware updates. | Select when cost sensitivity outweighs write speed requirements and legacy stock is available. |
| MX28F256J3F | JEDEC-compatible 256K parallel EEPROM; 5 ms page write; requires 12V VPP for programming. | Needs external high-voltage generator - increases board complexity and component count. | Choose only if existing system already implements VPP circuitry and MXIC qualification is mandated. |
Compared with AT28C256-15SU, the AT28C256F-15SU-T delivers 3× faster page writes without layout changes; versus MX28F256J3F, it eliminates VPP dependency while maintaining JEDEC pin compatibility - making it the optimal drop-in upgrade for industrial systems requiring reliable, low-complexity nonvolatile storage.
Availability
AT28C256F-15SU-T is available at Aetrix Electronics and suitable for industrial PLCs, legacy BIOS modules, calibration data loggers, and motor drive parameter storage requiring stable component supply across extended production lifecycles.
Supply support for AT28C256F-15SU-T 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 is a global semiconductor company specializing in microcontrollers, analog devices, and memory solutions, with emphasis on industrial, automotive, and aerospace reliability standards.
The AT28C256 product line delivers high-endurance, paged parallel EEPROMs designed for legacy system upgrades, firmware storage, and configuration retention in harsh environments where flash endurance or serial interface latency are limiting factors.
FAQ
What is the page write cycle time specification for AT28C256F-15SU-T?
The AT28C256F-15SU-T has a maximum page write cycle time of 3 ms, confirmed in Microchip's DS20006386B datasheet Section 6.8. This distinguishes it from the standard AT28C256-15 variant (10 ms), enabling faster firmware updates and parameter writes in time-constrained applications. The 3 ms rating applies across the full industrial temperature range (-40°C to +85°C) and 5V ±10% supply.
Does AT28C256F-15SU-T require external high-voltage programming circuitry?
No, AT28C256F-15SU-T operates with a single 5V ±10% supply for both read and write operations. Unlike older EPROMs or some EEPROMs requiring 12V VPP, this device integrates internal charge pumps and voltage regulation - eliminating external high-voltage generators and simplifying PCB design. The optional 12V on A9 is only for accessing the 64-byte device ID area, not for main array programming.
How does DATA Polling work on AT28C256F-15SU-T?
During a write cycle, reading the last written byte returns the complement of that data on I/O7. Once the internal programming completes, true data appears on I/O7 - signaling readiness for the next operation. This mechanism allows the host processor to poll I/O7 without halting other bus activity, and is fully supported in AT28C256F-15SU-T per Section 6.14 of DS20006386B.
Is AT28C256F-15SU-T pin-compatible with standard 28-pin SOIC SRAMs like 62256?
Yes, AT28C256F-15SU-T uses the JEDEC-approved byte-wide pinout identical to 62256 SRAM and 27C256 EPROM. Pin-for-pin mapping includes A0–A14, I/O0–I/O7, CE, OE, WE, VCC, and GND. However, timing behavior differs: AT28C256F-15SU-T requires WE-controlled write initiation and supports page writes, whereas SRAMs respond instantly to write strobes.
What is the endurance rating of AT28C256F-15SU-T?
The AT28C256F-15SU-T is rated for 10,000 write/erase cycles, as specified in Section 4.3 of DS20006386B. This endurance level is sufficient for applications involving infrequent updates - such as factory calibration storage, BIOS parameter retention, or PLC configuration archiving - and is guaranteed over the full industrial temperature range and supply voltage window.
AT28C256F-15SU-T Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Microchip Technology
- Series:
- -
- Package/Case:
- 28-SOIC (0.295", 7.50mm Width)
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- 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:
- 150 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
AT28C256F-15SU-T FAQ
1.How can I place an order for AT28C256F-15SU-T through Aetrix?
Please submit a Request for Quotation (RFQ) for AT28C256F-15SU-T 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 AT28C256F-15SU-T reliable?
The price and inventory of AT28C256F-15SU-T are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for AT28C256F-15SU-T is usually 5 days.
3.What payment methods are accepted for AT28C256F-15SU-T?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for AT28C256F-15SU-T transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for AT28C256F-15SU-T?
AT28C256F-15SU-T orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your AT28C256F-15SU-T 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 AT28C256F-15SU-T?
For technical support, including AT28C256F-15SU-T datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your AT28C256F-15SU-T requirements.
6.How does Aetrix verify that AT28C256F-15SU-T is sourced from the original manufacturer or authorized distributors?
All AT28C256F-15SU-T 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 AT28C256F-15SU-T meets industry standards.
7.What is the process for return or replacement of AT28C256F-15SU-T?
All AT28C256F-15SU-T units undergo pre-shipment inspection (PSI). If there is an issue with AT28C256F-15SU-T, 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 AT28C256F-15SU-T part is unused and in its original packaging.
Return procedure for AT28C256F-15SU-T:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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