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Microchip Technology AT28HC256E-90JU
- Part No.:
- AT28HC256E-90JU
- Manufacturer:
- Microchip Technology
- Category:
- Memory
- Package:
- 32-LCC (J-Lead)
- Datasheet:
-
AT28HC256E-90JU.pdf
- Description:
- IC EEPROM 256KBIT PAR 32PLCC
- Quantity:
- Payment:
- Shipping:
Inventory:2,925
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Product details
Overview
AT28HC256E-90JU from Microchip Technology is a 256-Kbit (32,768 × 8) parallel EEPROM with 90 ns read access time, single 5V ±10% supply operation, and industrial temperature range (–40°C to +85°C). It supports 1–64-byte page writes with ≤10 ms internal write cycle time, hardware/software data protection, and DATA Polling for write completion detection - deployed in embedded control firmware storage and industrial PLC configuration memory.
For engineers reviewing the AT28HC256E-90JU datasheet, AT28HC256E-90JU pinout, AT28HC256E-90JU application, or AT28HC256E-90JU equivalent, key selection criteria include byte-wide JEDEC-compliant pinout compatibility, 100,000 write endurance, 10-year data retention, and support for both hardware VCC-sense write inhibit and software-controlled data protection.
Technical Context
The AT28HC256E-90JU implements a static RAM-compatible parallel interface with dual-line chip enable (CE) and output enable (OE) control to prevent bus contention. Its internal 64-byte page register latches address and data during page write operations, freeing the bus for concurrent system activity.
Write completion is verified via DATA Polling on I/O7 (complement-to-data during write, true data after completion) or Toggle Bit behavior on I/O6, both usable at any point during the internal programming period. The device integrates VCC sense, 5 ms power-on delay, noise filtering on WE/CE, and optional 3-byte software command sequence for data protection enable/disable.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Memory Density | 256 Kbit (32,768 × 8), enabling full firmware image or multi-parameter configuration storage in space-constrained industrial controllers |
| Read Access Time | 90 ns max - meets timing requirements for 10 MHz CPU bus interfaces without wait states |
| Page Write Cycle Time | ≤10 ms - enables efficient bulk parameter updates without prolonged system blocking |
| Write Endurance | 100,000 cycles - supports frequent field calibration or logging in test equipment and instrumentation |
| Data Retention | 10 years at +85°C - ensures long-term reliability in unattended industrial deployments |
| Supply Voltage | 5V ±10% - compatible with legacy 5V logic systems and avoids need for dedicated voltage regulation |
| Operating Temperature | –40°C to +85°C - certified for use in factory automation, motor drives, and outdoor metering |
| Interface Standard | JEDEC byte-wide pinout - guarantees drop-in replacement compatibility with existing PCB layouts using standard EEPROM footprints |
Pinout & Package
AT28HC256E-90JU is packaged in a 32-lead PLCC (Plastic Leaded Chip Carrier) with JEDEC-standard byte-wide pinout. Pin 1 and Pin 17 are designated "Don't Connect" per datasheet; all other pins follow defined address, data, and control functions.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| A0–A14 | Address Inputs | 15-bit address bus supporting full 32,768-word addressing; A6–A14 define page boundaries for 64-byte page writes |
| I/O0–I/O7 | Bidirectional Data Bus | 8-bit parallel data path; I/O7 used for DATA Polling, I/O6 for Toggle Bit status indication during writes |
| CE | Chip Enable | Active-low chip select; must be low with OE low and WE high for read access; initiates write when pulsed low with OE high |
| OE | Output Enable | Active-low output control; places I/O lines in high-impedance state when high, preventing bus contention |
| WE | Write Enable | Active-low write strobe; controls byte or page write initiation; combined with CE for robust write inhibit logic |
| VCC | Power Supply | +5V ±10% main supply; internal VCC sense circuitry disables writes below ~3.8V to prevent corruption during brownout |
| GND | Ground Reference | Signal and power return; decoupling capacitor placement near Pin 16 critical for stable read/write timing |
| NC / DC | No Connect / Don't Connect | Pins 1 and 17 are unconnected; must remain floating - no routing or soldering permitted |
Key Features
| Feature | Design Value |
|---|---|
| Automatic Page Write | Internal 64-byte latch and timer eliminate external write sequencing logic and reduce host CPU overhead by >80% vs. byte-by-byte writes |
| DATA Polling | I/O7 toggles complement-to-data during write, enabling real-time polling without dedicated status registers or interrupts |
| Hardware Write Inhibit | VCC sense + 5 ms power-on delay + noise filtering on WE/CE prevents spurious writes during power-up, reset, or EMI events |
| Software Data Protection | 3-byte command sequence (AAh/55h/A0h) enables/disables write protection - preserves configuration integrity across power cycles |
| Device Identification Area | 64-byte reserved EEPROM block (7FC0h–7FFFh) accessible via 12V on A9 for unique serialization or calibration data storage |
| Green Packaging | RoHS-compliant PLCC package with lead-free terminations - satisfies environmental compliance for global industrial shipments |
Applications
| Industrial PLC Configuration Storage | Embedded Firmware Bootloader |
|---|---|
Use Scenario: Storing user-defined I/O mapping, PID tuning parameters, and alarm thresholds in programmable logic controllers operating in harsh factory environments. IC Role / Device Role / Timing Role: Nonvolatile configuration memory accessed via parallel bus during startup and runtime reconfiguration; 90 ns read speed supports deterministic scan-cycle timing. Use Value: 100,000 write cycles and 10-year data retention ensure reliable parameter persistence over 10+ years of continuous operation without backup batteries. | Use Scenario: Holding bootloader code and secure boot keys in microcontroller-based edge devices requiring field-upgradable firmware. IC Role / Device Role / Timing Role: External parallel boot memory mapped into MCU address space; software data protection prevents unauthorized firmware modification. Use Value: Hardware VCC-sense and software lock mechanisms jointly eliminate risk of accidental corruption during brownout or debug sessions. |
| Test Equipment Calibration Data | Metering Device Energy Registers |
Use Scenario: Recording factory calibration coefficients, linearity corrections, and sensor offset values in benchtop multimeters and signal generators. IC Role / Device Role / Timing Role: High-reliability parameter store updated infrequently but requiring guaranteed integrity; accessed only during calibration mode or power-up. Use Value: Optional 12V-programmable identification area (7FC0h–7FFFh) enables permanent device serialization and traceability per unit. | Use Scenario: Maintaining cumulative kWh, demand intervals, and tariff schedules in smart electricity meters exposed to wide ambient temperature swings. IC Role / Device Role / Timing Role: Industrial-grade nonvolatile memory operating continuously at –40°C to +85°C; page write minimizes flash wear in high-write-rate billing applications. Use Value: 10 ms max page write time allows energy register updates within tight metering interrupt windows without missing pulse counts. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar parallel EEPROM applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| AT28C256-90JU | Same 256-Kbit density and 90 ns speed, but rated for 10,000 write cycles and lacks software data protection | Suitable for low-update-rate applications like fixed configuration storage where extended endurance is unnecessary | Select when cost sensitivity outweighs need for 100k-cycle endurance or software lock features |
| FM24CL256-G | F-RAM with unlimited endurance and 150 ns read access; operates at 2.7–3.6V only; no 5V compatibility | Used where frequent writes dominate (e.g., real-time data logging), but requires voltage translation in 5V systems | Choose only if system redesign accommodates 3V operation and F-RAM's faster write latency justifies architecture change |
Compared with AT28C256-90JU, the AT28HC256E-90JU delivers 10× higher endurance and integrated software protection - critical for field-updatable systems. Versus FM24CL256-G, it maintains native 5V compatibility and JEDEC pinout but trades unlimited writes for proven EEPROM reliability in temperature-stressed industrial settings.
Availability
AT28HC256E-90JU is available at Aetrix Electronics and suitable for industrial PLC configuration storage, embedded bootloader memory, test equipment calibration data retention, and smart metering energy registers requiring stable component supply across extended production lifecycles.
Supply support for AT28HC256E-90JU 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 U.S.-based semiconductor company specializing in microcontrollers, analog devices, and nonvolatile memory solutions, with a focus on industrial, automotive, and aerospace reliability standards.
The AT28HC256 product line delivers high-speed, high-endurance parallel EEPROMs designed specifically for mission-critical firmware and configuration storage in industrial control, instrumentation, and metering applications.
FAQ
What is the maximum write endurance specification for the AT28HC256E-90JU?
The AT28HC256E-90JU is rated for 100,000 write/erase cycles - confirmed in the official Microchip datasheet DS20006428B, Section "Features" and Table 4-2. This extended endurance variant (denoted by the "E" suffix) exceeds the base AT28HC256's 10,000-cycle rating and is validated under industrial temperature conditions (–40°C to +85°C).
Does the AT28HC256E-90JU support both hardware and software write protection?
Yes, the AT28HC256E-90JU implements dual-layer write protection: hardware-level VCC sensing (disables writes below ~3.8V), power-on delay (~5 ms), and noise filtering on WE/CE inputs; plus software data protection enabled via a documented 3-byte command sequence (AAh → 55h → A0h to address 5555h/2AAAh/5555h). Both mechanisms are active simultaneously in the AT28HC256E-90JU.
What package type and pin count does the AT28HC256E-90JU use?
The AT28HC256E-90JU uses a 32-lead Plastic Leaded Chip Carrier (PLCC) package, as specified in Microchip's DS20006428B datasheet Section "Packages" and Figure 1-1. Pins 1 and 17 are designated "Don't Connect" and must remain unconnected; the remaining 30 pins implement JEDEC-standard byte-wide address, data, and control signals.
How is write completion detected on the AT28HC256E-90JU?
Write completion on the AT28HC256E-90JU is detected using either DATA Polling (monitoring I/O7 for transition from complement-to-data to true data) or the Toggle Bit method (observing toggling on I/O6 until it stabilizes). Both methods are functional at any time during the internal write cycle and require no additional hardware - fully documented in Sections 6.14 and 6.16 of the AT28HC256E-90JU datasheet.
Is the AT28HC256E-90JU compatible with 5V TTL and CMOS logic families?
Yes, the AT28HC256E-90JU features CMOS and TTL compatible inputs and outputs, as explicitly stated in the "Features" section of DS20006428B. Input voltage thresholds meet TTL (VIL ≤ 0.8V, VIH ≥ 2.0V) and CMOS (VIH ≥ 70% VCC) requirements, and output drive strength (VOL ≤ 0.45V at 6 mA, VOH ≥ 2.4V at –4 mA) ensures interoperability with standard 5V logic interfaces.
AT28HC256E-90JU Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Microchip Technology
- Series:
- -
- Package/Case:
- 32-LCC (J-Lead)
- Packaging:
- Tube
- Product Status:
- Active
- Programmable:
- 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:
- 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:
- 32-PLCC (13.97x11.43)
AT28HC256E-90JU FAQ
1.How can I place an order for AT28HC256E-90JU through Aetrix?
Please submit a Request for Quotation (RFQ) for AT28HC256E-90JU 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 AT28HC256E-90JU reliable?
The price and inventory of AT28HC256E-90JU are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for AT28HC256E-90JU is usually 5 days.
3.What payment methods are accepted for AT28HC256E-90JU?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for AT28HC256E-90JU transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for AT28HC256E-90JU?
AT28HC256E-90JU orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your AT28HC256E-90JU 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 AT28HC256E-90JU?
For technical support, including AT28HC256E-90JU datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your AT28HC256E-90JU requirements.
6.How does Aetrix verify that AT28HC256E-90JU is sourced from the original manufacturer or authorized distributors?
All AT28HC256E-90JU 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 AT28HC256E-90JU meets industry standards.
7.What is the process for return or replacement of AT28HC256E-90JU?
All AT28HC256E-90JU units undergo pre-shipment inspection (PSI). If there is an issue with AT28HC256E-90JU, 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 AT28HC256E-90JU part is unused and in its original packaging.
Return procedure for AT28HC256E-90JU:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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