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Microchip Technology AT28HC256E-70PI
- Part No.:
- AT28HC256E-70PI
- Manufacturer:
- Microchip Technology
- Category:
- Memory
- Package:
- 28-DIP (0.600", 15.24mm)
- Datasheet:
-
AT28HC256E-70PI.pdf
- Description:
- IC EEPROM 256KBIT PARALLEL 28DIP
- Quantity:
- Payment:
- Shipping:
Inventory:1,813
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Product details
Overview
AT28HC256E-70PI from Microchip Technology (formerly Atmel) is a 256 Kbit (32K × 8) parallel EEPROM with 70 ns read access time, JEDEC-standard byte-wide pinout, and industrial temperature range (–40°C to +85°C). It supports page write (1–64 bytes), DATA polling, and hardware/software data protection. Used in firmware storage, configuration memory, and boot code retention for embedded controllers.
For engineers reviewing the AT28HC256E-70PI datasheet, AT28HC256E-70PI pinout, AT28HC256E-70PI application, or AT28HC256E-70PI equivalent, key selection criteria include 70 ns read speed, 100K write endurance, 3 mA standby current, page-write capability, and industrial-grade TSOP-28 packaging.
Technical Context
The AT28HC256E-70PI operates as a drop-in SRAM-compatible nonvolatile memory: reads require CE and OE low with WE high; writes initiate on falling edge of CE or WE. Its internal 64-byte page register latches address and data, enabling concurrent bus release during internal programming.
Write completion is confirmed via DATA polling (I/O7 complement toggle) or I/O6 toggle bit detection. Hardware protection includes VCC sense (<3.8 V inhibits write), 5 ms power-on delay, noise filtering (<15 ns pulses ignored), and CE/OE/WE state-based write inhibit.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Memory Size | 256 Kbit (32,768 × 8), organized as byte-addressable parallel EEPROM |
| Read Access Time | 70 ns - enables direct replacement for fast SRAM in legacy boot and config circuits |
| Page Write Cycle | Max 10 ms - supports burst programming of up to 64 bytes without external timing control |
| Endurance | 100,000 write/erase cycles - validated high-endurance option (E suffix) for field-updatable systems |
| Standby Current | 3 mA at VCC = 5 V - meets low-power requirements in always-on industrial controllers |
| Supply Voltage | 5 V ± 10% - single-rail compatibility with TTL/CMOS logic and legacy 5 V microcontroller buses |
| Operating Temperature | –40°C to +85°C - qualified for industrial environments including factory automation and motor drives |
Pinout & Package
AT28HC256E-70PI 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.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| A0–A14 | Address Inputs | 15-bit address bus for full 32K-word addressing; A6–A14 define page boundaries for 64-byte page writes |
| I/O0–I/O7 | Bidirectional Data Bus | 8-bit parallel interface; supports true read/write data transfer and DATA polling (I/O7) or toggle bit (I/O6) |
| CE | Chip Enable | Active-low chip select; must be low with OE low for read, or low with WE low for write initiation |
| OE | Output Enable | Active-low output control; high during write to prevent bus contention; required high for page write |
| WE | Write Enable | Active-low write strobe; falling edge latches address/data; used with CE for dual-control write safety |
| VCC, GND | Power Supply | Single 5 V supply; decoupling required within 10 mm of pins per JEDEC layout guidelines |
Key Features
| Feature | Design Value |
|---|---|
| JEDEC Byte-wide Pinout | Direct drop-in replacement for industry-standard 27C256, 27C512, and 62256 SRAM in existing PCB layouts |
| 64-byte Page Register | Reduces system bus occupancy during multi-byte writes - frees address/data bus after initial latch |
| DATA Polling & Toggle Bit | Eliminates need for fixed write-timing delays; enables real-time status monitoring without external hardware |
| Software Data Protection (SDP) | User-configurable write lock via 3-byte command sequence; persists across power cycles and prevents accidental firmware corruption |
| 12 V Device Identification Area | 64-byte dedicated EEPROM region (7FC0H–7FFFH) accessible at 12 V for unique device serialization or calibration data |
Applications
| Industrial PLC Firmware Storage | Automotive ECU Configuration Memory |
|---|---|
Use Scenario: Storing ladder logic firmware and I/O mapping tables in programmable logic controllers requiring field updates and long-term data retention. IC Role / Device Role / Timing Role: Nonvolatile program memory with 70 ns read access, enabling real-time execution from memory-mapped address space. Use Value: 100K endurance and 10-year data retention ensure reliable operation over 15+ year equipment lifecycles in unattended installations. | Use Scenario: Holding calibration parameters, VIN-specific settings, and diagnostic fault logs in engine control units operating under thermal cycling. IC Role / Device Role / Timing Role: Industrial-temperature EEPROM interfaced directly to 8051 or C167 microcontrollers via parallel bus. Use Value: –40°C to +85°C rating and hardware write protection prevent corruption during cold cranking or under-hood thermal transients. |
| Medical Device Bootloader Storage | Networking Equipment Configuration Backup |
Use Scenario: Securing bootloader code and regulatory-compliant initialization routines in Class II medical instruments subject to IEC 62304. IC Role / Device Role / Timing Role: Read-critical boot memory with deterministic 70 ns access; software data protection prevents unauthorized firmware modification. Use Value: SDP enable/disable command sequence provides auditable write control, satisfying traceability and revision-lock requirements. | Use Scenario: Retaining switch/router MAC tables, VLAN configurations, and failover policies in carrier-grade Ethernet switches. IC Role / Device Role / Timing Role: Parallel EEPROM accessed by ARM9 or MIPS SoC during boot and runtime configuration reload. Use Value: Page write capability allows atomic 64-byte config saves, avoiding partial writes during power loss events. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar parallel EEPROM applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| AT28HC256-70PI | Standard endurance: 10K cycles; 10 ms max page write | Lower-cost option for infrequently updated systems | Select when firmware/config update frequency is <100×/year and cost sensitivity outweighs longevity needs |
| AT28HC256F-70PI | Fast write option: 3 ms max page write; same 10K endurance | Reduced programming latency for high-throughput manufacturing or diagnostics | Choose when production line flash programming time or field service update speed is critical |
Compared with AT28HC256-70PI and AT28HC256F-70PI, the AT28HC256E-70PI uniquely balances high endurance (100K cycles) with industrial temperature support and 70 ns read speed-making it optimal for systems requiring both long-term reliability and frequent field updates.
Availability
AT28HC256E-70PI is available at Aetrix Electronics and suitable for industrial PLC firmware storage, automotive ECU configuration memory, and medical device bootloader storage requiring stable component supply across extended product lifecycles.
Supply support for AT28HC256E-70PI 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, delivering high-reliability parallel EEPROMs for legacy and upgrade designs.
The AT28HC256 product line was designed for pin-compatible migration from EPROM and battery-backed SRAM in industrial, automotive, and medical systems requiring deterministic nonvolatile storage without external circuitry.
FAQ
What is the maximum page write size supported by the AT28HC256E-70PI?
The AT28HC256E-70PI supports page write operations of 1 to 64 bytes per internal programming cycle. All bytes written in a single page operation must reside on the same 64-byte page, defined by address bits A6–A14. The AT28HC256E-70PI's internal page register latches the full 64-byte block, allowing the host bus to be released immediately after data loading.
Does the AT28HC256E-70PI require a 12 V supply for normal operation?
No, the AT28HC256E-70PI operates from a single 5 V ± 10% supply during standard read/write operations. A 12 V ± 0.5 V supply is required only for accessing the optional 64-byte device identification area (addresses 7FC0H–7FFFH); this is not needed for main array reads, writes, or page programming. The AT28HC256E-70PI remains fully functional at 5 V in all standard modes.
How does software data protection (SDP) function on the AT28HC256E-70PI?
SDP on the AT28HC256E-70PI is enabled or disabled using specific 3-byte command sequences written to fixed addresses (5555H, 2AAAH, then 5555H or 80H). Once enabled, all subsequent writes require retransmission of the full sequence before data is accepted. The AT28HC256E-70PI retains SDP state across power cycles, providing persistent protection against accidental overwrites.
Can the AT28HC256E-70PI be used as a direct replacement for the AT28HC256-70PI on an existing PCB?
Yes - the AT28HC256E-70PI shares identical pinout, timing, voltage, and logic-level specifications with the AT28HC256-70PI. The only difference is enhanced endurance (100K vs. 10K cycles), which imposes no layout or signal integrity changes. The AT28HC256E-70PI is a backward-compatible upgrade requiring zero PCB modifications.
What package type is used for the AT28HC256E-70PI, and is it RoHS compliant?
The AT28HC256E-70PI uses a 28-lead Plastic Thin Small Outline Package (TSOP Type I, 8 mm × 13.4 mm), per JEDEC MO-183. It is RoHS compliant and offered in green (Pb/halide-free) packaging, meeting IPC/JEDEC J-STD-609A Class 1 marking requirements. The AT28HC256E-70PI's TSOP-28 footprint is compatible with standard SMT reflow profiles for lead-free assembly.
AT28HC256E-70PI 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:
- 10ms
- Access Time:
- 70 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
AT28HC256E-70PI FAQ
1.How can I place an order for AT28HC256E-70PI through Aetrix?
Please submit a Request for Quotation (RFQ) for AT28HC256E-70PI 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-70PI reliable?
The price and inventory of AT28HC256E-70PI are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for AT28HC256E-70PI is usually 5 days.
3.What payment methods are accepted for AT28HC256E-70PI?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for AT28HC256E-70PI transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for AT28HC256E-70PI?
AT28HC256E-70PI orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your AT28HC256E-70PI 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-70PI?
For technical support, including AT28HC256E-70PI datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your AT28HC256E-70PI requirements.
6.How does Aetrix verify that AT28HC256E-70PI is sourced from the original manufacturer or authorized distributors?
All AT28HC256E-70PI 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-70PI meets industry standards.
7.What is the process for return or replacement of AT28HC256E-70PI?
All AT28HC256E-70PI units undergo pre-shipment inspection (PSI). If there is an issue with AT28HC256E-70PI, 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-70PI part is unused and in its original packaging.
Return procedure for AT28HC256E-70PI:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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