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Microchip Technology AT28C64-15SI
- Part No.:
- AT28C64-15SI
- Manufacturer:
- Microchip Technology
- Category:
- Memory
- Package:
- 28-SOIC (0.295", 7.50mm Width)
- Datasheet:
-
AT28C64-15SI.pdf
- Description:
- IC EEPROM 64KBIT PARALLEL 28SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:3,145
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Product details
Overview
AT28C64-15SI from Atmel is a 64 Kbit (8K × 8) parallel EEPROM with 150 ns read access time, 1 ms byte write cycle, and CMOS/TTL-compatible I/O. It operates at 5V ±10%, supports industrial temperature range (–40°C to +85°C), and features READY/BUSY signaling and DATA polling for embedded microcontroller systems requiring nonvolatile storage with direct SRAM-like interface.
For engineers reviewing the AT28C64-15SI datasheet, AT28C64-15SI pinout, AT28C64-15SI application, or AT28C64-15SI equivalent, key selection criteria include JEDEC-standard 28-pin SOIC package compatibility, self-timed write with internal latching, VCC-sense write protection, chip clear capability, and 10-year data retention at industrial temperatures.
Technical Context
The AT28C64-15SI implements a parallel byte-wide EEPROM architecture with dual-line chip enable (CE) and output enable (OE) control, enabling bus contention avoidance in multi-device systems. Its internal address/data latches and control timer eliminate external timing components during byte writes.
Write completion detection is supported via open-drain RDY/BUSY (pin 1) or DATA polling on I/O7 - both methods are fully functional in the -15SI variant. The device integrates VCC-sense circuitry that inhibits writes below 3.8 V and enforces a 5 ms power-on delay before write enable.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Memory Size | 64 Kbit (8,192 × 8 bits); sufficient for firmware patch storage or configuration tables in resource-constrained controllers. |
| Read Access Time | 150 ns max; enables direct replacement of SRAM in legacy 8-bit microprocessor buses without wait-state insertion. |
| Byte Write Time | 1 ms typical; self-timed with no external clock required - simplifies host firmware logic for nonvolatile updates. |
| Supply Voltage | 5 V ±10%; compatible with standard TTL/CMOS logic rails and eliminates need for dedicated voltage regulators. |
| Operating Temperature | –40°C to +85°C; qualified for industrial environments including motor drives and PLC I/O modules. |
| Standby Current | 100 µA max (CMOS mode); enables low-power operation in battery-backed or energy-sensitive applications. |
| Data Retention | 10 years minimum; guaranteed under industrial temperature conditions without refresh cycles. |
| Endurance | 10,000 write/erase cycles; validated for field-updatable calibration data or infrequently modified system parameters. |
Pinout & Package
AT28C64-15SI is supplied in a 28-lead, 0.300" wide plastic gull-wing small outline (SOIC) package per JEDEC MS-012 standard, with pin 1 designated by index mark and pin 17 as NC (No Connect).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| A0–A12 | Address Inputs | 13-bit address bus for accessing full 8K-word memory space; TTL/CMOS compatible thresholds. |
| I/O0–I/O7 | Bidirectional Data Bus | 8-bit parallel data path; high-impedance when CE or OE is high to prevent bus contention. |
| CE | Chip Enable | Active-low chip select; must be low for read/write; enables standby current reduction when deasserted. |
| OE | Output Enable | Active-low output gate; used with CE to control read timing and avoid bus conflicts. |
| WE | Write Enable | Active-low write strobe; falling edge latches address, rising edge latches data for self-timed byte write. |
| RDY/BUSY | Open-Drain Status Output | Low during write cycle; released upon completion; supports wired-OR connection across multiple devices. |
| VCC | Power Supply | +5 V ±10% supply input; powers core logic and memory array; includes internal VCC-sense for write inhibit. |
| GND | Ground Reference | Signal and power return; decoupling capacitor placement near this pin is critical for noise immunity. |
Key Features
| Feature | Design Value |
|---|---|
| Self-timed Byte Write | Internal timer automates erase-before-write sequence - removes host timing dependency and reduces firmware overhead. |
| DATA Polling Support | I/O7 toggles complement-to-data during write; allows polling without dedicated status lines or interrupt resources. |
| JEDEC Byte-wide Pinout | Pin-compatible with industry-standard EPROMs and SRAMs - enables drop-in replacement in existing PCB layouts. |
| VCC Sense Write Protection | Hardware-level inhibition below 3.8 V prevents corruption during brown-out or power ramp-up conditions. |
| Chip Clear Function | 12 V on OE + WE pulse clears entire memory to FFh - useful for factory reset or secure data erasure. |
| 32-Byte ID Area | User-accessible EEPROM region (1FE0h–1FFFh) for serialization, calibration data, or firmware version tracking. |
Applications
| Industrial PLC Configuration Storage | Legacy Microcontroller Firmware Patching |
|---|---|
Use Scenario: Storing user-defined I/O mapping and alarm thresholds in programmable logic controllers operating in harsh factory environments. IC Role / Device Role / Timing Role: Nonvolatile configuration memory accessed via 8-bit parallel bus; reads occur during boot and runtime parameter lookup; writes only during commissioning or update events. Use Value: 10-year data retention and –40°C to +85°C qualification ensure reliable operation across thermal cycling and long maintenance intervals. | Use Scenario: Field-updating bootloader code or sensor calibration constants in 8051- or Z80-based embedded instruments with no external programming hardware. IC Role / Device Role / Timing Role: Directly mapped into microprocessor address space as SRAM-equivalent memory; uses RDY/BUSY or DATA polling to synchronize writes without CPU stalls. Use Value: 150 ns read speed avoids wait states; self-timed 1 ms write eliminates need for precise timing loops or external timers. |
| Medical Device Calibration Data Archive | Automotive Body Control Module Settings |
Use Scenario: Archiving factory-calibrated ADC offset/gain coefficients and patient-specific settings in portable diagnostic equipment. IC Role / Device Role / Timing Role: Dedicated nonvolatile storage for safety-critical parameters; accessed only during power-up initialization or service-mode reconfiguration. Use Value: 10,000-cycle endurance supports lifetime recalibration; VCC-sense protection prevents accidental overwrites during battery swaps or low-voltage conditions. | Use Scenario: Storing seat position memory, mirror presets, and lighting profiles in automotive body control units with CAN-linked master controllers. IC Role / Device Role / Timing Role: Local configuration memory interfaced to an 8-bit MCU; updated via serial command translation and parallel write bursts. Use Value: JEDEC pinout ensures compatibility with legacy BOMs; industrial temp rating matches under-hood ECU requirements. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar parallel EEPROM applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| AT28C64B-15SI | Enhanced revision with improved data retention (20 years) and reduced standby current (50 µA); same pinout and AC timing. | Preferred for new designs requiring extended lifecycle support or lower quiescent power in always-on modules. | Select AT28C64B-15SI if long-term obsolescence mitigation or sub-100 µA standby is mandatory. |
| MX28LV640BTC-15G | 64 Kbit parallel EEPROM with 150 ns access but requires 12 V for chip erase; no RDY/BUSY pin; different pin 1 function (NC instead of RDY/BUSY). | Suitable where board layout accommodates missing RDY/BUSY or where chip erase is infrequent and externally managed. | Choose MX28LV640BTC-15G only if RDY/BUSY is unused and 12 V programming infrastructure already exists. |
Compared with AT28C64-15SI, the AT28C64B-15SI offers longer data retention and lower standby current with identical footprint and timing, while MX28LV640BTC-15G lacks RDY/BUSY signaling and requires external 12 V for chip erase - limiting drop-in usability in real-time systems.
Availability
AT28C64-15SI is available at Aetrix Electronics and suitable for industrial PLCs, legacy microcontroller firmware updates, and medical calibration data storage requiring stable component supply across extended production lifecycles.
Supply support for AT28C64-15SI 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 company specializing in microcontrollers, nonvolatile memory, and wireless solutions before its acquisition by Microchip Technology in 2016.
The AT28C64 product line delivers parallel-interface EEPROMs optimized for direct integration into 8-bit microprocessor systems needing reliable, low-power, pin-compatible nonvolatile storage with minimal external support circuitry.
FAQ
What is the maximum read access time specified for the AT28C64-15SI?
The AT28C64-15SI has a maximum read access time of 150 ns, measured from address valid to valid data output under industrial temperature conditions (–40°C to +85°C) and 5 V ±10% supply. This value is guaranteed across all operating corners and enables seamless integration into 8 MHz and slower microprocessor buses without wait-state insertion. The AT28C64-15SI achieves this performance using Atmel's CMOS EEPROM process with optimized sense amplifier design.
Does the AT28C64-15SI support both RDY/BUSY signaling and DATA polling for write completion detection?
Yes, the AT28C64-15SI supports both RDY/BUSY signaling and DATA polling. Pin 1 functions as an open-drain RDY/BUSY output that pulls low during write cycles and releases upon completion. Simultaneously, DATA polling is implemented by reading I/O7 - it returns the complement of the written data until the write finishes, then outputs true data. Both methods are fully operational in the AT28C64-15SI and provide flexible host synchronization options without requiring additional hardware.
What package type and pin count does the AT28C64-15SI use?
The AT28C64-15SI uses a 28-lead, 0.300" wide plastic gull-wing small outline (SOIC) package, compliant with JEDEC MS-012. It has 28 pins arranged in two rows, with pin 1 identified by a notch or index mark. Pin 17 is designated NC (No Connect), and pin 1 serves as RDY/BUSY - distinguishing it from the AT28C64X variant where pin 1 is NC. This SOIC package enables surface-mount assembly and is compatible with standard reflow profiles.
How does the AT28C64-15SI protect against inadvertent writes during power transitions?
The AT28C64-15SI incorporates three hardware-level write protections: (1) VCC sense circuitry disables writes when supply drops below ~3.8 V; (2) a 5 ms internal power-on delay timer prevents writes until VCC stabilizes; and (3) write inhibition via standard control signals - holding CE high, OE low, or WE high blocks all write operations. These mechanisms ensure data integrity during brown-out, cold start, or noisy power conditions - a critical feature confirmed in the AT28C64-15SI datasheet's "WRITE PROTECTION" section.
Can the AT28C64-15SI be used as a direct replacement for standard SRAM in existing designs?
Yes, the AT28C64-15SI can operate as a direct read replacement for 8K × 8 SRAM due to identical pinout (JEDEC byte-wide), compatible timing, and TTL/CMOS I/O levels. Reads behave identically - asserting data when CE and OE are low and WE is high. However, writes differ: the AT28C64-15SI requires a self-timed byte write cycle (~1 ms), whereas SRAM writes are immediate. Host firmware must accommodate this difference using RDY/BUSY or DATA polling - but no PCB changes are needed for read-only or controlled-write integration.
AT28C64-15SI 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:
- 1ms
- Access Time:
- 150 ns
- Voltage - Supply:
- 4.5V ~ 5.5V
- Operating Temperature:
- -40°C ~ 85°C (TC)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 28-SOIC
AT28C64-15SI FAQ
1.How can I place an order for AT28C64-15SI through Aetrix?
Please submit a Request for Quotation (RFQ) for AT28C64-15SI 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 AT28C64-15SI reliable?
The price and inventory of AT28C64-15SI are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for AT28C64-15SI is usually 5 days.
3.What payment methods are accepted for AT28C64-15SI?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for AT28C64-15SI transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for AT28C64-15SI?
AT28C64-15SI orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your AT28C64-15SI 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 AT28C64-15SI?
For technical support, including AT28C64-15SI datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your AT28C64-15SI requirements.
6.How does Aetrix verify that AT28C64-15SI is sourced from the original manufacturer or authorized distributors?
All AT28C64-15SI 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 AT28C64-15SI meets industry standards.
7.What is the process for return or replacement of AT28C64-15SI?
All AT28C64-15SI units undergo pre-shipment inspection (PSI). If there is an issue with AT28C64-15SI, 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 AT28C64-15SI part is unused and in its original packaging.
Return procedure for AT28C64-15SI:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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