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Microchip Technology AT28C64X-20PC
- Part No.:
- AT28C64X-20PC
- Manufacturer:
- Microchip Technology
- Category:
- Memory
- Package:
- 28-DIP (0.600", 15.24mm)
- Datasheet:
-
AT28C64X-20PC.pdf
- Description:
- IC EEPROM 64KBIT PARALLEL 28DIP
- Quantity:
- Payment:
- Shipping:
Inventory:1,057
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Product details
Overview
AT28C64X-20PC from Atmel is a 64 Kbit (8K × 8) parallel EEPROM with JEDEC-standard byte-wide pinout, 200 ns read access time, 1 ms or 200 µs byte write capability, and CMOS/TTL-compatible I/O - used in embedded systems for nonvolatile configuration storage, firmware patching, and calibration data retention.
For engineers reviewing the AT28C64X-20PC datasheet, AT28C64X-20PC pinout, AT28C64X-20PC application, or AT28C64X-20PC equivalent, this page delivers verified timing specs, RDY/BUSY behavior, DATA polling implementation, endurance (10⁴/10⁵ cycles), and industrial-grade (-40°C to +85°C) operation under 5V ±10% supply.
Technical Context
The AT28C64X-20PC operates as a drop-in SRAM-compatible nonvolatile memory: reads require CE and OE low with WE high; writes initiate on falling WE (or CE) edge with address/data latched internally. It implements self-timed byte write with automatic clear-before-write and internal control timer - eliminating external timing logic.
Two hardware-based write completion detection methods are supported: DATA polling (I/O7 complement toggle) and RDY/BUSY output - though RDY/BUSY is unconnected (NC) on the AT28C64X variant. Write protection includes VCC sense (<3.8 V inhibition), 5 ms power-on delay, and triple-input inhibit (OE high, CE high, or WE high).
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Memory Size | 64 Kbit (8,192 × 8 bits) - supports full system configuration storage without external address decoding. |
| Read Access Time | 200 ns max - enables direct interface with 5 MHz microcontrollers without wait states. |
| Byte Write Time | 1 ms standard or 200 µs (AT28C64E variant only); AT28C64X-20PC uses 1 ms - impacts firmware update latency. |
| Endurance | 10,000 write/erase cycles - sufficient for field calibration or infrequent parameter updates. |
| Data Retention | 10 years at +85°C - validated for long-life industrial deployments without refresh. |
| Supply Voltage | 5V ±10% - compatible with legacy 5V logic families and mixed-voltage board designs. |
| Operating Temp | -40°C to +85°C - qualified for industrial temperature range per ordering code suffix 'I' or 'PI'. |
Pinout & Package
AT28C64X-20PC is supplied in a 28-lead, 0.600" wide plastic DIP (PDIP) package per JEDEC MS-011 AB. Pin 1 is NC (no connect) - RDY/BUSY function is disabled per AT28C64X variant specification.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| A0–A12 | Address Inputs | 13-bit address bus supporting full 8K-word addressing; TTL/CMOS compatible. |
| I/O0–I/O7 | Bidirectional Data Bus | 8-bit parallel interface; supports true read/write without direction control pins. |
| CE | Chip Enable | Active-low chip select; enables device for read/write when low - critical for multi-chip memory decoding. |
| OE | Output Enable | Active-low output gate; places I/O lines in high-Z when high - prevents bus contention during shared-bus operation. |
| WE | Write Enable | Active-low write strobe; initiates self-timed byte write on falling edge - no external timing circuitry required. |
| RDY/BUSY | Open-Drain Status Output | No-connect (NC) on AT28C64X variant - write completion must be detected via DATA polling only. |
| VCC, GND | Power Supply | Single 5V supply; 30 mA active current and 100 µA standby current enable low-power operation. |
Key Features
| Feature | Design Value |
|---|---|
| Self-timed byte write | Internal latching and timer eliminate need for external write pulse generation or timing control logic. |
| DATA polling support | I/O7 toggles complement during write - allows software-driven write completion detection without status pins. |
| JEDEC-standard pinout | Pin-compatible with industry-standard 28-pin parallel EEPROMs and SRAMs - simplifies PCB layout reuse. |
| VCC sense write protection | Automatic write disable below 3.8 V - prevents corruption during brown-out or power ramp conditions. |
| 32-byte ID area | User-accessible EEPROM block at 1FE0H–1FFFH - enables unique device serialization or firmware version tagging. |
Applications
| Industrial PLC Configuration Storage | Medical Device Calibration Data |
|---|---|
|
Use Scenario: Storing sensor calibration coefficients and operational thresholds in programmable logic controllers deployed in factory automation environments. IC Role / Device Role / Timing Role: Nonvolatile configuration memory interfaced directly to 8051 or Z80-based controller buses using CE/OE/WE handshaking. Use Value: 10-year data retention at +85°C ensures calibration integrity across extended maintenance cycles without battery backup. |
Use Scenario: Holding patient-specific calibration parameters and safety-critical setup values in portable diagnostic equipment. IC Role / Device Role / Timing Role: Standalone parallel EEPROM providing tamper-resistant, field-updatable storage independent of main processor boot sequence. Use Value: VCC-sense write protection prevents accidental overwrites during power transitions - critical for regulatory compliance (IEC 62304). |
| Telecom Line Card Firmware Patching | Automotive ECU Parameter Tables |
|
Use Scenario: Storing hot-swappable firmware patches and feature-enabling flags on carrier-grade line cards requiring zero-downtime updates. IC Role / Device Role / Timing Role: Byte-erasable memory enabling selective reprogramming of functional blocks without full flash erase cycles. Use Value: 200 ns read access supports real-time instruction fetch during active call processing - no performance penalty vs. SRAM. |
Use Scenario: Retaining adaptive learning tables (e.g., fuel trim, idle air control) in engine control units exposed to under-hood thermal stress. IC Role / Device Role / Timing Role: Industrial-temperature EEPROM integrated into CAN-connected ECU subsystems for persistent parameter logging. Use Value: -40°C to +85°C qualification and 10⁴-cycle endurance match automotive reprogramming requirements per SAE J1850. |
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 | Successor revision with improved data retention (100 years @ 25°C) and tighter tACC tolerance; RDY/BUSY remains NC. | Same pinout and timing; preferred for new designs requiring extended archival reliability. | Select AT28C64B-20PC if long-term data integrity beyond 10 years is required - otherwise AT28C64X-20PC remains fully functional. |
| MX28LV640BTC-20G | 3.3V-only supply; 200 ns access; 100K endurance; supports both BYTE and PAGE write modes. | Requires level-shifting for 5V systems; better suited for low-power, high-endurance applications where voltage scaling is acceptable. | Choose MX28LV640BTC-20G only in 3.3V-native designs - not a drop-in replacement due to incompatible VCC and I/O voltage levels. |
Compared with AT28C64X-20PC, AT28C64B-20PC offers superior data retention without layout changes, while MX28LV640BTC-20G enables lower power and higher endurance but mandates voltage translation and firmware adaptation for 5V systems.
Availability
AT28C64X-20PC is available at Aetrix Electronics and suitable for industrial control, medical instrumentation, telecom infrastructure, and automotive subsystems requiring stable component supply across extended product lifecycles.
Supply support for AT28C64X-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 fabless semiconductor company specializing in microcontrollers, nonvolatile memory, and secure authentication ICs.
The AT28C64X series was designed as a pin-compatible, SRAM-drop-in parallel EEPROM for legacy 5V embedded systems requiring field-updatable nonvolatile storage without redesign.
FAQ
What is the RDY/BUSY functionality on AT28C64X-20PC?
The RDY/BUSY pin (Pin 1) is designated as "No Connect" (NC) on the AT28C64X-20PC per its datasheet revision. Unlike earlier AT28C64 variants, this version disables the open-drain status output - write completion must be detected exclusively via DATA polling on I/O7. This design choice reduces pin count complexity while maintaining full functional compatibility for software-controlled systems.
Does AT28C64X-20PC support fast 200 µs byte writes?
No - the AT28C64X-20PC implements the standard 1 ms byte write cycle. The 200 µs write option is exclusive to the AT28C64E variant (e.g., AT28C64E-20PC), which is explicitly marked with an "E" suffix. The "X" in AT28C64X denotes a specific revision with NC RDY/BUSY and standard endurance (10⁴ cycles), not enhanced speed.
How is write protection implemented on AT28C64X-20PC?
AT28C64X-20PC employs three-tiered hardware write protection: (1) VCC sense disables writes below ~3.8 V; (2) a 5 ms internal power-on delay prevents writes during supply ramp-up; and (3) simultaneous assertion of OE high, CE high, or WE high inhibits all write operations. These features ensure robust immunity to spurious writes during power transients or software glitches.
Can AT28C64X-20PC be used as a direct replacement for standard SRAM in existing designs?
Yes - AT28C64X-20PC uses JEDEC-standard byte-wide pinout and identical read timing to common 8K×8 SRAMs (e.g., 6264). It responds to CE/OE/WE signals identically during reads, allowing drop-in substitution. However, write cycles require software awareness of self-timed behavior and DATA polling - unlike SRAM's immediate write completion.
What is the purpose of the 32-byte ID area in AT28C64X-20PC?
The 32-byte user-accessible EEPROM block at addresses 1FE0H–1FFFH provides dedicated space for device-specific data such as serial numbers, manufacturing date codes, firmware version stamps, or calibration checksums. It is accessed using the same CE/OE/WE protocol as main memory - enabling traceability and field diagnostics without consuming primary storage capacity.
AT28C64X-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
AT28C64X-20PC FAQ
1.How can I place an order for AT28C64X-20PC through Aetrix?
Please submit a Request for Quotation (RFQ) for AT28C64X-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 AT28C64X-20PC reliable?
The price and inventory of AT28C64X-20PC are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for AT28C64X-20PC is usually 5 days.
3.What payment methods are accepted for AT28C64X-20PC?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for AT28C64X-20PC transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for AT28C64X-20PC?
AT28C64X-20PC orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your AT28C64X-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 AT28C64X-20PC?
For technical support, including AT28C64X-20PC datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your AT28C64X-20PC requirements.
6.How does Aetrix verify that AT28C64X-20PC is sourced from the original manufacturer or authorized distributors?
All AT28C64X-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 AT28C64X-20PC meets industry standards.
7.What is the process for return or replacement of AT28C64X-20PC?
All AT28C64X-20PC units undergo pre-shipment inspection (PSI). If there is an issue with AT28C64X-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 AT28C64X-20PC part is unused and in its original packaging.
Return procedure for AT28C64X-20PC:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
AT28C64X-20PC Tags
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M24C02-WMN6TP
STMicroelectronics
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AT24C02C-XHM-T
Microchip Technology
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AT21CS01-STUM10-T
Microchip Technology
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AT24C02C-SSHM-T
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24LC01BT-I/OT
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M24C02-FMC6TG
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AT24CS02-SSHM-T
Microchip Technology
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93LC46BT-I/OT
Microchip Technology
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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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