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Microchip Technology AT28C64E-20SC
- Part No.:
- AT28C64E-20SC
- Manufacturer:
- Microchip Technology
- Category:
- Memory
- Package:
- 28-SOIC (0.295", 7.50mm Width)
- Datasheet:
-
AT28C64E-20SC.pdf
- Description:
- IC EEPROM 64KBIT PARALLEL 28SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:2,837
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Product details
Overview
AT28C64E-20SC from Microchip Technology (formerly Atmel) is a 64 Kbit (8K × 8) parallel EEPROM with JEDEC-standard byte-wide pinout, 200 µs fast byte write time, 120 ns read access, and CMOS/TTL-compatible I/O. It operates at 5V ±10%, supports commercial temperature range (0°C to 70°C), and is used in firmware storage, configuration memory, and boot code retention for microcontroller-based systems.
For engineers reviewing the AT28C64E-20SC datasheet, AT28C64E-20SC pinout, AT28C64E-20SC application, or AT28C64E-20SC equivalent, key selection criteria include self-timed write cycle, RDY/BUSY output support, DATA polling capability, 100,000-cycle endurance, and SOIC-28 package compatibility with legacy 8-bit bus interfaces.
Technical Context
The AT28C64E-20SC implements a parallel EEPROM architecture with internal address/data latching and an autonomous control timer that manages erase-before-write sequencing without external timing components. Its READY/BUSY open-drain output and I/O7 data polling provide two hardware- and software-based methods to detect write completion.
It features VCC sense (write inhibit below 3.8 V), 5 ms power-on delay before write enable, and triple-level write protection via CE/OE/WE logic states. The device includes 32 bytes of dedicated identification EEPROM accessible at addresses 1FE0H–1FFFH using A9 = 12 V.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Memory Size | 64 Kbit (8,192 × 8 bits); sufficient for small firmware images or persistent configuration tables in resource-constrained embedded systems. |
| Read Access Time | 200 ns maximum; enables direct interfacing with 5 MHz microprocessor buses without wait-state insertion. |
| Byte Write Time | 200 µs maximum (AT28C64E variant); reduces full-memory rewrite time to ~1.6 seconds versus 8 seconds for standard 1 ms version. |
| Endurance | 100,000 write/erase cycles; supports frequent field-updatable parameters in industrial controllers and metering devices. |
| Data Retention | 10 years at 25°C; ensures long-term reliability for unattended equipment such as remote sensors or network infrastructure. |
| Supply Voltage | 5 V ±10%; compatible with legacy 5 V logic families and eliminates need for level-shifting in retrofitted designs. |
| Standby Current | 100 µA typical (CMOS mode); suitable for battery-backed applications where low quiescent power is critical. |
Pinout & Package
AT28C64E-20SC is supplied in a 28-lead, 0.300" wide plastic gull-wing small outline (SOIC) package per JEDEC MS-012, with 1.27 mm lead pitch and surface-mount footprint.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| A0–A12 | Address Inputs | 13-bit address bus supporting full 8K-word addressing; compatible with Z80, 8051, and 68K family address lines. |
| I/O0–I/O7 | Bidirectional Data Bus | 8-bit parallel interface; high-impedance when CE or OE is high, enabling shared bus operation without external tristate logic. |
| CE | Chip Enable | Active-low chip select; must be low for read/write access; enables multi-device memory decoding on common bus. |
| OE | Output Enable | Active-low output control; allows output gating independent of CE, preventing bus contention during partial decode. |
| WE | Write Enable | Active-low write strobe; initiates self-timed byte write on falling edge; latches address and data internally. |
| RDY/BUSY | Open-Drain Status Output | Actively pulled low during write; released high-Z at completion; supports wired-OR connection for multi-chip status monitoring. |
| VCC | Power Supply | +5 V supply input; requires local 0.1 µF ceramic decoupling near pin for stable read/write operation. |
| GND | Ground Reference | Signal and power ground return; must be connected to system ground plane with low-inductance path. |
Key Features
| Feature | Design Value |
|---|---|
| Self-timed byte write | Eliminates need for external write timing circuitry; internal control timer handles erase-before-write sequence automatically. |
| RDY/BUSY + DATA polling | Dual write-completion detection: hardware-ready signal (pin 1) and software-pollable I/O7 bit for flexible system integration. |
| VCC sense & power-on delay | Prevents inadvertent writes during power ramp-up; inhibits write until VCC ≥3.8 V and holds 5 ms before enabling WE. |
| JEDEC byte-wide pinout | Direct drop-in replacement for SRAM and EPROM in existing 28-pin sockets; no PCB redesign required for migration. |
| 32-byte ID memory | User-accessible EEPROM block at 1FE0H–1FFFH (A9 = 12 V); supports serialization, calibration data, or firmware version tracking. |
Applications
| Industrial PLC Configuration Storage | Legacy Embedded System Boot Memory |
|---|---|
|
Use Scenario: Storing I/O mapping, PID tuning parameters, and alarm thresholds in programmable logic controllers deployed in factory automation environments. IC Role / Device Role / Timing Role: Nonvolatile configuration memory accessed during startup and runtime parameter updates; retains values across power cycles. Use Value: Enables field reconfiguration without firmware reflashing; 100,000-cycle endurance supports daily parameter adjustments over 10+ years. |
Use Scenario: Holding boot loader and minimal OS kernel for 8-bit microcontrollers in medical diagnostic instruments with strict qualification requirements. IC Role / Device Role / Timing Role: Primary boot ROM mapped into CPU address space; read at reset vector; supports in-system updates via serial interface. Use Value: 200 ns access time meets timing budgets of 5 MHz Z80/8051 derivatives; 5 V compatibility avoids voltage translation in legacy designs. |
| Point-of-Sale Terminal Settings | Telecom Line Card Calibration Data |
|
Use Scenario: Retaining tax rate tables, language packs, and printer settings in retail terminals operating 24/7 with infrequent firmware updates. IC Role / Device Role / Timing Role: Static RAM-equivalent read/write memory; accessed via parallel bus during initialization and operator menu changes. Use Value: Low 100 µA standby current extends backup battery life; RDY/BUSY output synchronizes UI updates with write completion. |
Use Scenario: Storing analog front-end trim values and line impedance compensation coefficients in DSLAM line cards requiring recalibration after hardware swaps. IC Role / Device Role / Timing Role: Calibration memory written once per card installation and read at power-on; accessed via microcontroller GPIO-banked parallel interface. Use Value: 10-year data retention ensures calibration integrity across product lifecycle; 12 V A9 programming enables secure ID memory partitioning. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar parallel EEPROM applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| AT28C64B-20SC | Lower endurance (10,000 cycles) and 1 ms write time; same pinout, speed grade, and SOIC package. | Suitable for static configuration storage with rare updates (e.g., factory-set defaults), not for frequent field updates. | Select AT28C64B-20SC only if cost sensitivity outweighs endurance requirements and write latency is acceptable. |
| ST M28W640ECB90N1 | 64 Mbit capacity, 90 ns access, 3.3 V core (with 5 V I/O tolerance); different pinout and command protocol (not JEDEC byte-wide). | Requires PCB redesign and firmware driver changes; suited for high-density, low-power upgrades-not drop-in replacement. | Choose ST M28W640ECB90N1 only when migrating to higher density and lower voltage, accepting full hardware/software revision. |
Compared with AT28C64B-20SC, the AT28C64E-20SC delivers 10× higher endurance and 5× faster write time-critical for dynamic parameter storage-while maintaining identical pinout and timing interface. Versus ST M28W640ECB90N1, it offers true plug-and-play compatibility but trades off density and modern voltage scaling.
Availability
AT28C64E-20SC is available at Aetrix Electronics and suitable for industrial control, legacy embedded system maintenance, and telecom infrastructure requiring stable component supply with long-lifecycle support.
Supply support for AT28C64E-20SC 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 its parallel EEPROM portfolio for legacy design support and industrial longevity.
The AT28C64 series was designed for direct replacement of EPROM and SRAM in 8-bit microprocessor systems, emphasizing pin compatibility, zero external timing components, and robust nonvolatile storage in harsh environments.
FAQ
What is the maximum write cycle time for AT28C64E-20SC?
The AT28C64E-20SC has a maximum byte write cycle time of 200 µs, verified per AC Write Characteristics table in the official datasheet. This is the defining feature of the "E" suffix variant and applies across all operating temperatures and supply voltages within specification. The standard AT28C64 (non-E) version requires up to 1 ms per byte write. AT28C64E-20SC achieves this performance through optimized internal charge pump and erase algorithms.
Does AT28C64E-20SC support both RDY/BUSY and DATA polling?
Yes, AT28C64E-20SC supports both RDY/BUSY status signaling and DATA polling. Pin 1 functions as an open-drain RDY/BUSY output that goes low during write and releases high-Z upon completion. Simultaneously, I/O7 toggles to the complement of written data during the write cycle and returns to true value when complete-enabling software-driven polling without external hardware. Both mechanisms are fully functional in the AT28C64E-20SC.
What package type is used for AT28C64E-20SC?
AT28C64E-20SC uses a 28-lead, 0.300" wide plastic gull-wing small outline (SOIC) package, designated as "28S" in Atmel's ordering nomenclature. It conforms to JEDEC MS-012 standards, has 1.27 mm lead pitch, and is RoHS-compliant. This package is pin-compatible with other 28-pin parallel memory devices including AT28C64B-20SC and legacy 27C64 EPROMs in SOIC-28 footprints.
Can AT28C64E-20SC be used as a direct replacement for AT28C64-20SC?
No-AT28C64E-20SC is not a direct replacement for AT28C64-20SC due to differences in endurance and write timing. While both share identical pinout, speed grade (200 ns read), and SOIC-28 package, the AT28C64E-20SC offers 100,000 write cycles and 200 µs write time, whereas AT28C64-20SC provides only 10,000 cycles and 1 ms write time. Electrical and timing compatibility exists, but system-level validation is required if upgrading solely for endurance.
What is the purpose of the 32-byte ID memory in AT28C64E-20SC?
The 32-byte ID memory in AT28C64E-20SC resides at addresses 1FE0H–1FFFH and is accessed by raising A9 to 12 V ±0.5 V. It is intended for user-defined data such as device serial numbers, calibration coefficients, manufacturing date codes, or firmware version stamps. Unlike main array writes, ID memory programming follows the same self-timed byte write process but requires elevated A9 voltage-ensuring separation from routine configuration updates and preventing accidental overwrites.
AT28C64E-20SC Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Microchip Technology
- Series:
- -
- Package/Case:
- 28-SOIC (0.295", 7.50mm Width)
- Packaging:
- Tube
- Product Status:
- Obsolete
- Programmable:
- Not Verified
- Memory Type:
- Non-Volatile
- Memory Format:
- EEPROM
- Technology:
- EEPROM
- Memory Size:
- 64Kbit
- Memory Organization:
- 8K x 8
- Memory Interface:
- Parallel
- Clock Frequency:
- -
- Write Cycle Time - Word, Page:
- 200µs
- Access Time:
- 200 ns
- Voltage - Supply:
- 4.5V ~ 5.5V
- Operating Temperature:
- 0°C ~ 70°C (TC)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 28-SOIC
AT28C64E-20SC FAQ
1.How can I place an order for AT28C64E-20SC through Aetrix?
Please submit a Request for Quotation (RFQ) for AT28C64E-20SC 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 AT28C64E-20SC reliable?
The price and inventory of AT28C64E-20SC are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for AT28C64E-20SC is usually 5 days.
3.What payment methods are accepted for AT28C64E-20SC?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for AT28C64E-20SC transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for AT28C64E-20SC?
AT28C64E-20SC orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your AT28C64E-20SC 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 AT28C64E-20SC?
For technical support, including AT28C64E-20SC datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your AT28C64E-20SC requirements.
6.How does Aetrix verify that AT28C64E-20SC is sourced from the original manufacturer or authorized distributors?
All AT28C64E-20SC 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 AT28C64E-20SC meets industry standards.
7.What is the process for return or replacement of AT28C64E-20SC?
All AT28C64E-20SC units undergo pre-shipment inspection (PSI). If there is an issue with AT28C64E-20SC, 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 AT28C64E-20SC part is unused and in its original packaging.
Return procedure for AT28C64E-20SC:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
AT28C64E-20SC Tags
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M24C02-WMN6TP
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AT24C02C-XHM-T
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AT21CS01-STUM10-T
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