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Microchip Technology AT28HC256F-90JC
- Part No.:
- AT28HC256F-90JC
- Manufacturer:
- Microchip Technology
- Category:
- Memory
- Package:
- 32-LCC (J-Lead)
- Datasheet:
-
AT28HC256F-90JC.pdf
- Description:
- IC EEPROM 256KBIT PAR 32PLCC
- Quantity:
- Payment:
- Shipping:
Inventory:2,675
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Product details
Overview
AT28HC256F-90JC from Atmel is a 256 Kbit (32K × 8) parallel EEPROM with JEDEC-standard byte-wide pinout, 90 ns read access time, 3 ms page write cycle, and single 5V ±10% supply. It supports hardware/software data protection, DATA polling, and toggle-bit write completion detection for embedded firmware storage in industrial controllers and legacy system upgrades.
For engineers reviewing the AT28HC256F-90JC datasheet, AT28HC256F-90JC pinout, AT28HC256F-90JC application, or AT28HC256F-90JC equivalent, key selection criteria include its fast 3 ms page write capability (vs. 10 ms standard), 3 mA standby current at commercial temperature range, and TSOP-28 package compatibility with legacy SRAM-based designs requiring nonvolatile retention.
Technical Context
The AT28HC256F-90JC implements a CMOS-based parallel EEPROM architecture with internal 64-byte page latching and autonomous write timing via an on-chip control timer. Its dual-line chip enable (CE) and output enable (OE) logic enables bus contention avoidance in shared-memory systems.
Write operations support both byte and page modes, with page writes constrained to A6–A14-aligned 64-byte boundaries and strict 150 µs inter-byte load timing (tBLC). End-of-write detection uses either I/O7 DATA polling or I/O6 toggle-bit monitoring-both functional during active write cycles without external delay components.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Memory Density | 256 Kbit (32,768 × 8), directly replaces 32K × 8 SRAM/EPROM in pin-compatible designs |
| Read Access Time | 90 ns maximum - meets timing for 10 MHz bus interfaces without wait states |
| Page Write Cycle | 3 ms maximum (F-option) - reduces firmware update latency by 70% vs. 10 ms standard variant |
| Supply Voltage | 5V ±10% - operates from standard TTL/CMOS logic rails; no auxiliary voltage required |
| Standby Current | 3 mA at VCC = 5V, T = 25°C - enables low-power hold mode in battery-backed systems |
| Data Retention | 10 years minimum - guaranteed for long-life industrial deployments without refresh |
| Endurance | 10,000 write/erase cycles - sufficient for infrequent configuration or calibration storage |
Pinout & Package
AT28HC256F-90JC is packaged in a 28-lead Thin Small Outline Package (TSOP Type I, 8 × 13.4 mm), compliant with JEDEC MO-183 and RoHS/Green (Pb/Halide-free) requirements.
| 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 writes |
| 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 |
| CE | Chip Enable | Active-low device select; must be low with OE low and WE high for read access |
| OE | Output Enable | Active-low output control; enables high-impedance state when high to prevent bus contention |
| WE | Write Enable | Active-low write strobe; falling edge latches address/data; used with CE for byte/page write initiation |
| VCC, GND | Power Supply | Single 5V supply with decoupling recommended; ground pin located at position 14 per TSOP top view |
Key Features
| Feature | Design Value |
|---|---|
| Fast Page Write (3 ms) | Reduces firmware update time by 70% over standard 10 ms variants, critical for field-programmable devices |
| Hardware Write Inhibit | VCC sense (<3.8V), 5 ms power-on delay, and noise filtering (<15 ns pulses) prevent spurious writes during power transitions |
| Software Data Protection (SDP) | User-configurable 3-byte unlock sequence prevents accidental writes; remains active across power cycles |
| JEDEC Byte-Wide Pinout | Direct drop-in replacement for 28-pin SRAM/EPROM in legacy PCB layouts without redesign |
| Extended Temperature Range | Commercial grade (0°C to +70°C) ensures stability in office and light-industrial environments |
Applications
| Industrial PLC Configuration Storage | Legacy Embedded System Firmware Backup |
|---|---|
Use Scenario: Storing runtime configuration parameters and calibration tables in programmable logic controllers operating in factory-floor environments. IC Role / Device Role / Timing Role: Nonvolatile memory holding user-modifiable settings; accessed via parallel bus during boot or reconfiguration events. Use Value: 3 mA standby current extends backup battery life; 90 ns read speed supports real-time parameter recall without CPU wait states. | Use Scenario: Providing firmware image backup for microcontrollers in aging medical or test equipment where flash reprogramming is unreliable. IC Role / Device Role / Timing Role: Parallel-boot ROM replacement; holds verified firmware copies accessible via standard address/data bus. Use Value: JEDEC pinout allows direct socket replacement of obsolete EPROMs; 10-year data retention ensures long-term archival integrity. |
| Automotive Diagnostic Tool Calibration Memory | Point-of-Sale Terminal Parameter Storage |
Use Scenario: Holding vehicle-specific diagnostic routines and sensor compensation coefficients in handheld OBD-II tools. IC Role / Device Role / Timing Role: Read-mostly storage updated only during tool firmware updates; accessed randomly during diagnostic session setup. Use Value: Hardware write inhibit prevents corruption during vehicle ignition transients; 3 ms page writes accelerate field update procedures. | Use Scenario: Storing tax rates, language packs, and receipt formatting rules in retail terminals subject to regional regulatory changes. IC Role / Device Role / Timing Role: Field-upgradable configuration memory mapped into CPU address space; written infrequently but read on every transaction. Use Value: Software Data Protection prevents unauthorized parameter modification; 256 Kbit capacity accommodates multi-language localization data sets. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar parallel EEPROM applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| AT28HC256-90JC | 10 ms page write cycle; same pinout, timing, and package | Lacks 3 ms write acceleration; suitable where update speed is non-critical | Select when cost sensitivity outweighs firmware update latency requirements |
| MX28F256J3F | Intel-compatible 256 Kbit EEPROM; 120 ns read, 5 ms page write; PLCC-32 package | Requires PCB layout change due to different pin count and footprint | Choose for Intel 80x86-based systems already using MX28F family; verify SDP command compatibility |
Compared with AT28HC256-90JC, the AT28HC256F-90JC delivers 70% faster page writes without altering interface timing or voltage requirements; versus MX28F256J3F, it avoids PCB redesign but lacks Intel-specific command set extensions used in legacy x86 BIOS contexts.
Availability
AT28HC256F-90JC is available at Aetrix Electronics and suitable for industrial PLCs, legacy embedded system upgrades, and automotive diagnostic tools requiring stable component supply with long-lifecycle support.
Supply support for AT28HC256F-90JC 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
Atmel Corporation (now part of Microchip Technology) is a semiconductor manufacturer specializing in microcontrollers, nonvolatile memory, and secure authentication ICs.
The AT28HC256 product line was designed for pin-compatible, low-risk migration from EPROM/SRAM in industrial and telecom infrastructure where firmware reliability and long-term data retention are critical.
FAQ
What is the maximum page write cycle time for AT28HC256F-90JC?
The AT28HC256F-90JC has a maximum page write cycle time of 3 ms, confirmed in Section 16 "Page Mode Write Characteristics" of the official datasheet. This is the defining feature of the "F" option suffix and distinguishes it from the standard 10 ms AT28HC256-90JC. The 3 ms specification applies across the full commercial temperature range (0°C to +70°C) and is characterized-not just tested-to ensure design margin.
Does AT28HC256F-90JC support both hardware and software write protection?
Yes, AT28HC256F-90JC implements dual-layer write protection: hardware features include VCC sensing (<3.8V), 5 ms power-on delay, and noise filtering on WE/CE inputs; software protection uses a user-enabled 3-byte unlock sequence (AAh→55h→A0h) that persists across power cycles. Both mechanisms are fully documented in Sections 4.6.1 and 4.6.2 of the AT28HC256 datasheet.
Which package type is used for AT28HC256F-90JC?
AT28HC256F-90JC uses a 28-lead Plastic Thin Small Outline Package (TSOP Type I, 8 × 13.4 mm), designated as "28T" in Atmel's ordering guide. This green (Pb/Halide-free), surface-mount package complies with JEDEC MO-183 and is distinct from PDIP, PLCC, or PGA variants offered in the same speed grade.
Can AT28HC256F-90JC be used as a direct replacement for AT28HC256-90JC?
Yes, AT28HC256F-90JC is a pin- and function-compatible drop-in replacement for AT28HC256-90JC, sharing identical pinout, AC/DC specifications, and operating voltage. The sole functional difference is the reduced 3 ms page write time (vs. 10 ms), which does not affect read operation or interface timing-making it safe for retrofit into existing designs without layout or firmware changes.
What methods are available to detect write completion on AT28HC256F-90JC?
AT28HC256F-90JC provides two hardware-supported write completion detection methods: DATA polling (monitoring complement-to-data on I/O7) and toggle-bit detection (observing I/O6 toggling until stabilization). Both operate concurrently during write cycles and require no external components-enabling real-time status feedback without fixed delay loops.
AT28HC256F-90JC Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Microchip Technology
- Series:
- -
- Package/Case:
- 32-LCC (J-Lead)
- 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:
- 0°C ~ 70°C (TC)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 32-PLCC (13.97x11.43)
AT28HC256F-90JC FAQ
1.How can I place an order for AT28HC256F-90JC through Aetrix?
Please submit a Request for Quotation (RFQ) for AT28HC256F-90JC 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-90JC reliable?
The price and inventory of AT28HC256F-90JC are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for AT28HC256F-90JC is usually 5 days.
3.What payment methods are accepted for AT28HC256F-90JC?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for AT28HC256F-90JC transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for AT28HC256F-90JC?
AT28HC256F-90JC orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your AT28HC256F-90JC 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-90JC?
For technical support, including AT28HC256F-90JC datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your AT28HC256F-90JC requirements.
6.How does Aetrix verify that AT28HC256F-90JC is sourced from the original manufacturer or authorized distributors?
All AT28HC256F-90JC 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-90JC meets industry standards.
7.What is the process for return or replacement of AT28HC256F-90JC?
All AT28HC256F-90JC units undergo pre-shipment inspection (PSI). If there is an issue with AT28HC256F-90JC, 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-90JC part is unused and in its original packaging.
Return procedure for AT28HC256F-90JC:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
AT28HC256F-90JC Tags
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AT24C02C-XHM-T
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AT21CS01-STUM10-T
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M24C02-FMC6TG
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AT24CS02-SSHM-T
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93LC46BT-I/OT
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AT24C04C-SSHM-T
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24LC01BT-I/SN
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24AA02UIDT-I/OT
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