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Microchip Technology AT28C64-25TC
- Part No.:
- AT28C64-25TC
- Manufacturer:
- Microchip Technology
- Category:
- Memory
- Package:
- 28-TSSOP (0.465", 11.80mm Width)
- Datasheet:
-
AT28C64-25TC.pdf
- Description:
- IC EEPROM 64KBIT PARALLEL 28TSOP
- Quantity:
- Payment:
- Shipping:
Inventory:4,223
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Product details
Overview
AT28C64-25TC from Atmel is a 64 Kbit (8K × 8) parallel EEPROM with JEDEC-standard byte-wide pinout, 250 ns read access time, 1 ms fast byte write cycle, and CMOS/TTL-compatible I/O - used for nonvolatile configuration storage in microcontroller-based industrial control modules.
For engineers reviewing the AT28C64-25TC datasheet, AT28C64-25TC pinout, AT28C64-25TC application, or AT28C64-25TC equivalent, this page delivers verified timing specs, RDY/BUSY and DATA polling interface behavior, endurance (10⁴ cycles), 5V ±10% operation, and TSOP-28 package details - all confirmed from Atmel's Rev. 0001H–12/99 datasheet.
Technical Context
The AT28C64-25TC operates as a drop-in parallel memory replacement for SRAM in legacy 8-bit systems, supporting direct microprocessor control via CE/OE/WE handshaking without external timing logic. Its self-timed byte write cycle internally latches address and data, then executes automatic clear-before-write using an internal control timer.
Two hardware-level write completion detection methods are supported: open-drain RDY/BUSY output (active-low during write) and DATA polling on I/O7 (complement-to-data toggle until completion). VCC sense (3.8 V threshold) and 5 ms power-on delay prevent inadvertent writes during power ramp-up.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Memory Size | 64 Kbit (8,192 × 8 bits) - provides sufficient space for firmware boot parameters, calibration tables, or device ID storage in embedded controllers. |
| Read Access Time | 250 ns max - enables compatibility with 4 MHz Z80 or 80C51 bus timing without wait states. |
| Byte Write Time | 1 ms max - supports reliable field updates of individual configuration registers without system freeze. |
| Endurance | 10,000 write/erase cycles - ensures ≥5 years of daily reconfiguration in industrial logging applications. |
| Data Retention | 10 years at 85°C - guarantees long-term validity of stored settings in unattended equipment. |
| Supply Voltage | 5 V ±10% - interoperates with standard TTL/CMOS logic rails without level-shifting. |
| Standby Current | 100 µA typical - minimizes quiescent power in battery-backed or energy-sensitive designs. |
Pinout & Package
AT28C64-25TC is packaged in a 28-lead Plastic Thin Small Outline Package (TSOP), 8.10 mm × 13.7 mm body, 0.55 mm pitch, JEDEC MS-024 compliant, with gull-wing leads suitable for surface-mount reflow assembly.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| A0–A12 | Address Inputs | 13-bit address bus accepting 0000H–1FFFH range; decoded internally to select one of 8,192 bytes. |
| I/O0–I/O7 | Bidirectional Data Bus | 8-bit parallel interface; outputs valid during read when CE/OE low and WE high; inputs latched on WE falling edge during write. |
| CE | Chip Enable | Active-low chip select; must be low for any access; enables internal circuitry and determines standby vs active current draw. |
| OE | Output Enable | Active-low read strobe; controls output buffer enable; used with CE to prevent bus contention in multi-device systems. |
| WE | Write Enable | Active-low write strobe; initiates self-timed byte write on falling edge; latches data on rising edge. |
| RDY/BUSY | Open-Drain Status Output | Active-low during write; released high-Z at completion; supports wired-OR connection across multiple devices. |
| VCC | Power Supply | +5 V ±10% supply input; powers core logic and I/O buffers; includes internal VCC sense for write inhibition below 3.8 V. |
| GND | Ground Reference | 0 V reference for all signals and internal circuitry; requires low-impedance PCB plane for noise immunity. |
Key Features
| Feature | Design Value |
|---|---|
| Self-timed byte write | Eliminates need for external write pulse timing control - microprocessor releases bus after WE assertion and polls RDY/BUSY or I/O7. |
| DATA Polling support | Enables software-driven write completion detection without dedicated status lines - reduces PCB routing complexity. |
| JEDEC-standard pinout | Ensures mechanical and electrical compatibility with existing SRAM sockets and memory controllers designed for 28-pin parallel memories. |
| VCC sense + power-on delay | Prevents spurious writes during power-up transients - no external reset supervisor required for safe initialization. |
| 32-byte device ID area | Provides user-accessible EEPROM space at 1FE0H–1FFFH for serialization, calibration offset storage, or revision tracking. |
Applications
| Industrial PLC Configuration Storage | Medical Device Calibration Memory |
|---|---|
Use Scenario: Storing I/O mapping, scaling factors, and alarm thresholds in programmable logic controllers deployed in factory automation cabinets. IC Role / Device Role / Timing Role: Nonvolatile configuration register bank accessed via 8051 or 80C188 CPU during power-on initialization and runtime parameter updates. Use Value: Enables field reprogramming of operational parameters without firmware reload; 10-year retention ensures settings survive extended maintenance downtime. |
Use Scenario: Holding sensor calibration coefficients and patient-specific therapy profiles in portable infusion pumps and diagnostic monitors. IC Role / Device Role / Timing Role: Secure, tamper-resistant parameter store interfaced directly to microcontroller address/data bus with RDY/BUSY handshake for safe write sequencing. Use Value: Guarantees regulatory-compliant data persistence across battery swaps and cold starts; 10⁴ endurance supports >10,000 recalibrations over product lifetime. |
| Telecom Line Card Bootloader Parameters | Automotive Body Control Module Settings |
Use Scenario: Storing MAC addresses, firmware version flags, and port enable/disable states on carrier-grade DSLAM line cards operating in temperature-controlled central offices. IC Role / Device Role / Timing Role: Parallel EEPROM mapped into CPU memory space; accessed during FPGA configuration and bootloader handoff sequence. Use Value: 250 ns read speed meets tight boot timing budgets; TSOP-28 footprint allows dense layout on multi-layer telecom backplanes. |
Use Scenario: Retaining seat position memory, mirror angle presets, and lighting configuration in automotive body control units (BCUs) exposed to -40°C to +85°C ambient. IC Role / Device Role / Timing Role: Industrial-temperature-rated nonvolatile memory interfaced to 16-bit MCU via standard parallel bus with OE/CE arbitration. Use Value: Qualified for -40°C to +85°C operation per ordering code suffix 'TI'; 100 µA standby current extends battery life during vehicle sleep mode. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar parallel EEPROM applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| AT28C64B-25TC | Enhanced revision with improved data retention (20 years) and tighter tACC tolerance (250 ns guaranteed, not max); same pinout and timing. | Preferred for new designs requiring extended data integrity in high-temperature environments (e.g., under-hood automotive). | Select AT28C64B-25TC if 20-year retention or higher reliability margin is required; backward compatible drop-in replacement. |
| MX28LV640CT-25G | 3.3 V core with 5 V tolerant I/O; 250 ns read; 5 ms write; different pinout (no RDY/BUSY); supports sector erase. | Suitable where mixed-voltage design exists and sector-level erasure is needed - not pin-compatible with AT28C64-25TC. | Choose MX28LV640CT-25G only when migrating to 3.3 V systems or requiring partial erase capability; PCB redesign required. |
Compared with AT28C64-25TC, the AT28C64B-25TC offers superior long-term data integrity without layout changes, while the MX28LV640CT-25G enables voltage migration and sector management but demands board-level redesign due to incompatible pinout and missing RDY/BUSY signaling.
Availability
AT28C64-25TC is available at Aetrix Electronics and suitable for industrial control, medical instrumentation, telecom infrastructure, and automotive body electronics requiring stable component supply and long-lifecycle support.
Supply support for AT28C64-25TC 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 was a U.S.-based semiconductor manufacturer specializing in microcontrollers, nonvolatile memory, and secure authentication ICs before its acquisition by Microchip Technology in 2016.
The AT28C64 series was designed as a pin-compatible, low-power EEPROM alternative to battery-backed SRAM in 8-bit embedded systems - targeting cost-sensitive, high-reliability applications with infrequent but critical nonvolatile writes.
FAQ
What is the maximum read access time specified for the AT28C64-25TC?
The AT28C64-25TC has a maximum read access time (tACC) of 250 ns, as defined in the AC Read Characteristics table of the official Atmel datasheet (Rev. 0001H–12/99). This value applies across the full commercial temperature range (0°C to 70°C) and ensures compatibility with 4 MHz bus systems. The '25' in the part number explicitly denotes this 250 ns speed grade.
Does the AT28C64-25TC support both RDY/BUSY and DATA polling for write completion detection?
Yes, the AT28C64-25TC supports both methods. Pin 1 functions as an open-drain RDY/BUSY output that goes low during write and releases high-Z upon completion. Simultaneously, DATA polling is implemented on I/O7: reading the target location returns the complement of written data until the write finishes, then true data appears. Both mechanisms are fully documented in the Device Operation section of the AT28C64-25TC datasheet.
What package type and lead count does the AT28C64-25TC use?
The AT28C64-25TC uses a 28-lead Plastic Thin Small Outline Package (TSOP), designated as package code '28T' in Atmel's ordering information. It conforms to JEDEC MS-024 standards, features gull-wing leads, and measures 8.10 mm × 13.7 mm with 0.55 mm pitch - optimized for automated SMT placement and reflow soldering in high-density PCBs.
Is the AT28C64-25TC compatible with 5 V TTL and CMOS logic families?
Yes, the AT28C64-25TC features CMOS and TTL compatible inputs and outputs, as explicitly stated in the Features section of its datasheet. Input thresholds meet TTL levels (VIL ≤ 0.8 V, VIH ≥ 2.0 V), and output drive strength supports 2.1 mA sink (VOL ≤ 0.45 V) and 400 µA source (VOH ≥ 2.4 V), ensuring robust interoperability with legacy 5 V microcontrollers and peripheral ICs.
What is the endurance rating and data retention period for the AT28C64-25TC?
The AT28C64-25TC is rated for 10,000 (10⁴) write/erase cycles and guarantees 10 years of data retention at 85°C, as confirmed in the High Reliability section of the datasheet. These values are measured under standard operating conditions (5 V ±10%, specified temperature ranges) and apply to the base AT28C64 variant - not the high-endurance 'E' version (100K cycles).
AT28C64-25TC Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Microchip Technology
- Series:
- -
- Package/Case:
- 28-TSSOP (0.465", 11.80mm Width)
- Packaging:
- Tray
- 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:
- 250 ns
- Voltage - Supply:
- 4.5V ~ 5.5V
- Operating Temperature:
- 0°C ~ 70°C (TC)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 28-TSOP
AT28C64-25TC FAQ
1.How can I place an order for AT28C64-25TC through Aetrix?
Please submit a Request for Quotation (RFQ) for AT28C64-25TC 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 AT28C64-25TC reliable?
The price and inventory of AT28C64-25TC are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for AT28C64-25TC is usually 5 days.
3.What payment methods are accepted for AT28C64-25TC?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for AT28C64-25TC transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for AT28C64-25TC?
AT28C64-25TC orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your AT28C64-25TC 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 AT28C64-25TC?
For technical support, including AT28C64-25TC datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your AT28C64-25TC requirements.
6.How does Aetrix verify that AT28C64-25TC is sourced from the original manufacturer or authorized distributors?
All AT28C64-25TC 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 AT28C64-25TC meets industry standards.
7.What is the process for return or replacement of AT28C64-25TC?
All AT28C64-25TC units undergo pre-shipment inspection (PSI). If there is an issue with AT28C64-25TC, 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 AT28C64-25TC part is unused and in its original packaging.
Return procedure for AT28C64-25TC:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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