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Microchip Technology AT28C64-20PC
- Part No.:
- AT28C64-20PC
- Manufacturer:
- Microchip Technology
- Category:
- Memory
- Package:
- 28-DIP (0.600", 15.24mm)
- Datasheet:
-
AT28C64-20PC.pdf
- Description:
- IC EEPROM 64KBIT PARALLEL 28DIP
- Quantity:
- Payment:
- Shipping:
Inventory:4,267
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Product details
Overview
AT28C64-20PC from Atmel is a 64K-bit (8K × 8) parallel EEPROM with JEDEC-standard byte-wide pinout, 200 ns read access time, 1 ms self-timed byte write cycle, and CMOS/TTL-compatible I/O - used in embedded systems for nonvolatile configuration storage, firmware patching, and calibration data retention.
For engineers reviewing the AT28C64-20PC datasheet, AT28C64-20PC pinout, AT28C64-20PC application, or AT28C64-20PC equivalent, key selection considerations include its 5V ±10% supply operation, RDY/BUSY and DATA polling write completion detection, industrial temperature range (–40°C to +85°C), and compatibility with microprocessor bus interfaces without external timing logic.
Technical Context
The AT28C64-20PC operates as a drop-in parallel memory replacement for SRAM in read cycles and implements internal address/data latching during byte writes, freeing the host bus. Its self-timed write cycle uses an on-chip control timer and automatic erase-before-write sequence.
It supports two hardware-based write completion detection methods: open-drain RDY/BUSY output (pin 1) and DATA polling via I/O7 complement behavior, enabling flexible integration into interrupt-driven or polling-based microcontroller systems.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Memory Size | 64 Kbit (8,192 × 8 bits) - provides sufficient space for boot code metadata, device ID, or small firmware patches in resource-constrained systems. |
| Read Access Time | 200 ns max - enables direct interfacing with 5 MHz microprocessors without wait states. |
| Byte Write Cycle | 1 ms typical - self-timed; no external timing circuitry required, simplifying system design. |
| VCC Supply | 5 V ±10% - compatible with legacy 5V logic families and mixed-voltage board designs. |
| Standby Current | 100 µA CMOS - supports low-power modes in battery-backed or energy-sensitive applications. |
| Endurance | 10,000 write/erase cycles - suitable for infrequent configuration updates, not high-frequency logging. |
| Data Retention | 10 years at +85°C - ensures long-term reliability in industrial environments without refresh. |
Pinout & Package
AT28C64-20PC is supplied in a 28-lead, 0.600" wide plastic DIP (PDIP) package per JEDEC MS-011 AB standard, with through-hole mounting and industry-standard footprint.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| A0–A12 | Address Inputs | 13-bit address bus for accessing all 8,192 memory locations; TTL/CMOS compatible. |
| I/O0–I/O7 | Bidirectional Data Bus | 8-bit parallel interface; tri-stated when CE or OE is high to prevent bus contention. |
| CE | Chip Enable | Active-low chip select; must be low for read/write access; controls standby current mode. |
| OE | Output Enable | Active-low read strobe; allows output control independent of CE for multiplexed bus sharing. |
| WE | Write Enable | Active-low write strobe; initiates self-timed byte write on falling edge with data latched on rising edge. |
| RDY/BUSY | Open-Drain Status Output | Actively pulled low during write; released high at completion - supports wired-OR multi-device status lines. |
| VCC | Power Supply | +5 V ±10% supply; includes VCC sense circuitry that inhibits writes below ~3.8 V. |
| GND | Ground Reference | Signal and power ground reference for all inputs, outputs, and internal logic. |
Key Features
| Feature | Design Value |
|---|---|
| Self-timed Byte Write | Eliminates need for external write pulse generation or timing logic - reduces BOM count and PCB area. |
| RDY/BUSY and DATA Polling | Dual write-completion detection methods enable flexible integration with interrupt-capable or polling-only microcontrollers. |
| Write Protection Logic | VCC sense, power-on delay (~5 ms), and signal-level inhibit (CE/OE/WE states) prevent accidental writes during power transitions. |
| JEDIC Byte-wide Pinout | Ensures compatibility with existing SRAM-based memory sockets and layout patterns, easing migration. |
| Industrial Temperature Range | –40°C to +85°C operation validated - supports deployment in automotive ECUs, industrial PLCs, and outdoor equipment. |
Applications
| Industrial Control Configuration Storage | Embedded System Boot Parameter Retention |
|---|---|
|
Use Scenario: Storing calibrated sensor offsets, PID tuning constants, and I/O mapping tables in programmable logic controllers. IC Role / Device Role / Timing Role: Nonvolatile configuration register bank accessed during startup and runtime reconfiguration. Use Value: Enables field-updatable calibration without firmware reflashing; retains settings across power loss. |
Use Scenario: Holding bootloader configuration flags, secure boot keys, and hardware revision identifiers in medical monitoring devices. IC Role / Device Role / Timing Role: Early-boot memory mapped at fixed address for initialization before DRAM/SRAM is configured. Use Value: Provides tamper-resistant, low-latency access to critical boot parameters with 200 ns read timing. |
| Firmware Patch Storage | Legacy System Memory Upgrade |
|
Use Scenario: Hosting hotfixes or minor firmware revisions in telecom line cards where full flash reprogramming is disruptive. IC Role / Device Role / Timing Role: Parallel-accessible patch memory mapped alongside main program memory. Use Value: Allows atomic patch activation via simple byte writes; avoids risk of bricking during in-field updates. |
Use Scenario: Replacing obsolete EPROMs (e.g., 27C64) in legacy test equipment requiring in-system reprogrammability. IC Role / Device Role / Timing Role: Pin-compatible EEPROM drop-in with identical 28-pin DIP footprint and JEDEC pinout. Use Value: Eliminates UV eraser dependency and socket programming; supports field updates without board removal. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar parallel EEPROM applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| AT28C64B-20PC | Revised version with improved data retention (20 years) and enhanced ESD protection; same 200 ns access, 1 ms write, and pinout. | Preferred for new designs requiring extended lifetime or higher robustness in noisy industrial environments. | Select AT28C64B-20PC if long-term data integrity or higher immunity to electrostatic discharge is required. |
| MX28F640KC-20PC | 64K-bit Flash memory (not EEPROM); requires sector erase before write; 200 ns read but no RDY/BUSY or DATA polling support. | Suitable only where bulk updates are acceptable and write-cycle flexibility is not needed. | Choose MX28F640KC-20PC only if cost-per-bit is critical and system firmware can accommodate erase-before-write constraints. |
Compared with AT28C64-20PC, AT28C64B-20PC offers longer data retention and better ESD tolerance while maintaining full functional and pin compatibility; MX28F640KC-20PC trades byte-level write flexibility for lower cost but introduces erase latency and lacks hardware write-status signaling.
Availability
AT28C64-20PC is available at Aetrix Electronics and suitable for industrial control systems, embedded medical devices, and legacy equipment upgrades requiring stable component supply, long-lifecycle support, and verified 5V parallel memory compatibility.
Supply support for AT28C64-20PC 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 AT28C64 product line was designed for embedded systems needing reliable, easy-to-integrate parallel EEPROM with microprocessor bus compatibility and industrial-grade endurance.
FAQ
What is the maximum operating temperature range for the AT28C64-20PC?
The AT28C64-20PC is rated for industrial temperature operation from –40°C to +85°C. This specification is confirmed in the DC and AC Operating Range table on page 4 of the official datasheet, and applies specifically to the "-20" speed grade with "PC" (PDIP) packaging. The AT28C64-20PC maintains full functionality and parameter compliance across this entire range.
Does the AT28C64-20PC support both RDY/BUSY and DATA polling simultaneously?
Yes, the AT28C64-20PC supports both RDY/BUSY status signaling (via open-drain pin 1) and DATA polling (via I/O7 complement behavior) for detecting write completion. These methods are functionally independent and may be used interchangeably or concurrently depending on system architecture - for example, using RDY/BUSY for interrupt-driven handling and DATA polling as a software fallback. Both are fully documented in the Device Operation section.
Is the AT28C64-20PC pin-compatible with standard 28-pin SRAMs like the 6264?
No, the AT28C64-20PC is not pin-compatible with the 6264 SRAM. While both use 28-pin PDIP packages and share address/data bus pin positions, the AT28C64-20PC substitutes RDY/BUSY for the 6264's CE2 and uses different control signal timing and logic levels. It follows JEDEC-approved byte-wide EEPROM pinout, not SRAM pinout - confirmed in the Pin Configurations section and Ordering Information table.
What write protection mechanisms does the AT28C64-20PC implement?
The AT28C64-20PC implements three hardware-based write protection mechanisms: (1) VCC sense - write inhibited if supply voltage drops below ~3.8 V; (2) power-on delay - automatic 5 ms lockout after VCC reaches threshold; and (3) signal-level inhibit - write disabled unless CE is low, OE is high, and WE is low. All are detailed in the WRITE PROTECTION subsection of the Device Operation section.
Can the AT28C64-20PC be used in place of the AT28C64-15PC in an existing design?
Yes, the AT28C64-20PC can replace the AT28C64-15PC in most cases, as both share identical pinout, voltage requirements, timing control logic, and functional behavior - differing only in maximum read access time (200 ns vs. 150 ns). Systems designed for the faster -15 variant will operate reliably with the -20 variant, though timing margins may tighten slightly; no PCB or firmware changes are required.
AT28C64-20PC 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:
- 64Kbit
- Memory Organization:
- 8K x 8
- Memory Interface:
- Parallel
- Clock Frequency:
- -
- Write Cycle Time - Word, Page:
- 1ms
- Access Time:
- 200 ns
- Voltage - Supply:
- 4.5V ~ 5.5V
- Operating Temperature:
- 0°C ~ 70°C (TC)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Through Hole
- Supplier Device Package:
- 28-PDIP
AT28C64-20PC FAQ
1.How can I place an order for AT28C64-20PC through Aetrix?
Please submit a Request for Quotation (RFQ) for AT28C64-20PC 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 AT28C64-20PC reliable?
The price and inventory of AT28C64-20PC are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for AT28C64-20PC is usually 5 days.
3.What payment methods are accepted for AT28C64-20PC?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for AT28C64-20PC transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for AT28C64-20PC?
AT28C64-20PC orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your AT28C64-20PC 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 AT28C64-20PC?
For technical support, including AT28C64-20PC datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your AT28C64-20PC requirements.
6.How does Aetrix verify that AT28C64-20PC is sourced from the original manufacturer or authorized distributors?
All AT28C64-20PC 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 AT28C64-20PC meets industry standards.
7.What is the process for return or replacement of AT28C64-20PC?
All AT28C64-20PC units undergo pre-shipment inspection (PSI). If there is an issue with AT28C64-20PC, 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 AT28C64-20PC part is unused and in its original packaging.
Return procedure for AT28C64-20PC:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
AT28C64-20PC Tags
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