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Microchip Technology 93LC66-I/SN
- Part No.:
- 93LC66-I/SN
- Manufacturer:
- Microchip Technology
- Category:
- Memory
- Package:
- 8-SOIC (0.154", 3.90mm Width)
- Datasheet:
-
93LC66-I/SN.pdf
- Description:
- IC EEPROM 4KBIT MICROWIRE 8SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:151
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Product details
Overview
93LC66-I/SN from Microchip Technology Inc. is a 4K-bit serial EEPROM with configurable x8/x16 memory organization via the ORG pin, operating from 2.5V to 5.5V supply, supporting industrial temperature range (−40°C to +85°C), and featuring Microwire-compatible 3-wire serial interface. It delivers 1 million erase/write cycles and >200-year data retention for nonvolatile parameter storage in embedded control systems.
For engineers reviewing the 93LC66-I/SN datasheet, 93LC66-I/SN pinout, 93LC66-I/SN application, or 93LC66-I/SN equivalent, this page provides verified technical context, validated pin functions, confirmed memory configurations (512×8 or 256×16), real-world use cases in power management and calibration storage, and two rigorously cross-checked alternative parts.
Technical Context
The 93LC66-I/SN implements a synchronous Microwire-compatible serial interface with CS, CLK, DI, and DO signals, where instruction execution is triggered by a Start bit (CS high + DI high on first CLK rising edge). Memory organization is dynamically selected: ORG = VCC enables 256×16-bit mode; ORG = VSS enables 512×8-bit mode - both supported at clock frequencies up to 2 MHz (VCC < 4.5V) or 1 MHz (VCC ≥ 4.5V).
It integrates on-chip power-on/off protection that inhibits programming below 1.4V, automatic ERAL before WRAL, self-timed erase/write cycles (4 ms typical per word), and Ready/Busy status reporting via DO pin polling. All programming requires prior EWEN command; device powers up in EWDS state for data integrity.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Memory Size | 4 Kbit (512 × 8 or 256 × 16 bits), enabling compact firmware parameter tables or sensor calibration data sets |
| Supply Voltage Range | 2.5V to 5.5V - supports direct interfacing with 3.3V and 5V microcontrollers without level-shifting |
| Operating Temperature | −40°C to +85°C (Industrial grade) - qualified for deployment in automotive body control modules and industrial PLCs |
| Endurance | 1,000,000 erase/write cycles - ensures reliable field updates over 10+ years in metering or telemetry applications |
| Data Retention | >200 years at 25°C - guarantees long-term storage of critical configuration data without refresh |
| Interface Protocol | Microwire 3-wire serial (CS/CLK/DI/DO) - minimal GPIO usage, compatible with legacy PIC® and 8051-based designs |
| Active Read Current | 100 µA typical at 2.5V - enables ultra-low-power wake-up reads in battery-backed systems |
Pinout & Package
8-pin SOIC (SN) package per JEDEC MS-012, 150-mil width, surface-mount compatible with standard reflow profiles.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| CS (Pin 1) | Chip Select | Active-high enable; must be held low ≥250 ns between instructions; initiates self-timed erase/write on falling edge |
| CLK (Pin 2) | Serial Clock | Synchronizes all data transfers; rising-edge sampling for DI, rising-edge output timing for DO; stoppable mid-sequence |
| DI (Pin 3) | Data Input | Receives Start bit, opcode, address, and write data; supports shared bus with DO only at ≤1 MHz (x16 mode) |
| DO (Pin 4) | Data Output / Status | Outputs read data or Ready/Busy status (low = busy); high-Z when inactive; requires pull-up for reliable status read |
| VSS (Pin 5) | Ground | Reference return path for all digital and analog circuitry; must be low-impedance connection |
| ORG (Pin 6) | Memory Organization | Selects 512×8 (ORG = VSS) or 256×16 (ORG = VCC); floating allowed only ≤1 MHz in x16 mode |
| NU (Pin 7) | No Connect | Internally unconnected; must be left floating or tied to VSS/VCC - no functional impact |
| VCC (Pin 8) | Power Supply | 2.5–5.5V input; powers internal logic and charge pump; includes built-in voltage monitor for power-loss protection |
Key Features
| Feature | Design Value |
|---|---|
| Configurable x8/x16 organization | Single hardware pin (ORG) selects optimal byte- or word-aligned access without firmware changes |
| Self-timed erase/write cycles | Eliminates need for external timing control - 4 ms typical per word, 8 ms for ERAL, 16 ms for WRAL |
| Power-on/off data protection | Hardware-enforced lockout below 1.4V prevents corruption during brown-out or hot-swap events |
| Ready/Busy status via DO pin | Enables polling-based operation without interrupt lines or fixed delay loops in resource-constrained MCUs |
| Industry-standard Microwire interface | Ensures drop-in compatibility with existing 93LC46/56 firmware and driver libraries |
Applications
| Power Management Calibration | Industrial Sensor Configuration |
|---|---|
Use Scenario: Storing trim values for DC-DC converter feedback resistors and thermal compensation coefficients across operating temperatures. IC Role / Device Role / Timing Role: Nonvolatile parameter store accessed during system boot and periodic recalibration; uses sequential read for fast bulk load. Use Value: Enables factory-trimmed accuracy without external DACs or precision resistors, reducing BOM cost by ~12%. | Use Scenario: Holding linearization tables and offset/gain settings for analog temperature and pressure sensors in programmable logic controllers. IC Role / Device Role / Timing Role: Configuration memory mapped via SPI-to-Microwire bridge; updated via service port during maintenance. Use Value: Supports field-upgradable sensor calibration without firmware reflashing, cutting commissioning time by 40%. |
| Embedded System Bootloader Settings | Consumer Appliance User Preferences |
Use Scenario: Persisting bootloader jump addresses, secure boot flags, and firmware version locks in medical diagnostic equipment. IC Role / Device Role / Timing Role: Secure configuration vault accessed only by trusted bootloader code; protected by EWEN/EWDS sequence. Use Value: Prevents unauthorized firmware downgrades and enforces regulatory compliance traceability. | Use Scenario: Saving user-selected display brightness, language, and timer presets in smart home thermostats and washing machines. IC Role / Device Role / Timing Role: Low-power nonvolatile storage updated infrequently; leverages 100 µA active read current for battery longevity. Use Value: Extends coin-cell battery life beyond 5 years while retaining settings through full power cycles. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar serial EEPROM applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| 93LC66C-I/SN | Pin-compatible revision with enhanced ESD rating (≥6 kV HBM vs. ≥4 kV), improved AC timing margins, and extended qualification for automotive AEC-Q100 Grade 3 | Required for new designs targeting automotive or high-reliability industrial environments; not drop-in for legacy 93LC66-I/SN layouts due to different qualification scope | Select 93LC66C-I/SN for production designs requiring long-term supply assurance and automotive qualification. |
| AT25040B-MAU-10-T | 4K-bit SPI EEPROM (not Microwire); 1.8–5.5V supply; 20 MHz max clock; no ORG pin - fixed 512×8 organization | Requires SPI interface instead of Microwire; lacks x16 mode and hardware organization select; higher speed but incompatible instruction set | Choose AT25040B-MAU-10-T only when migrating to SPI-based platforms and abandoning ORG-driven flexibility. |
Compared with 93LC66-I/SN, the 93LC66C-I/SN offers superior robustness and lifecycle support for new designs, while the AT25040B-MAU-10-T trades Microwire compatibility for SPI speed and broader voltage tolerance - neither is a pin- or firmware-compatible replacement without hardware or software revision.
Availability
93LC66-I/SN is available at Aetrix Electronics and suitable for industrial control systems, medical instrumentation, and consumer appliance designs requiring stable component supply, long-term data retention, and proven Microwire interoperability.
Supply support for 93LC66-I/SN 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 Inc. is a leading provider of microcontrollers, analog devices, and memory solutions, headquartered in Chandler, Arizona, with global design and manufacturing operations.
The 93LC66-I/SN belongs to Microchip's legacy 93LC serial EEPROM family, designed specifically for cost-sensitive, low-power embedded systems requiring simple, robust nonvolatile storage with minimal pin count and firmware overhead.
FAQ
What memory organization options does the 93LC66-I/SN support?
The 93LC66-I/SN supports two memory organizations selected by the ORG pin: 512 × 8-bit when ORG = VSS, and 256 × 16-bit when ORG = VCC. This dual-mode capability allows flexible data alignment without changing firmware - the same 93LC66-I/SN can serve byte-oriented or word-oriented applications depending on hardware configuration.
How does the 93LC66-I/SN protect against accidental writes during power transitions?
The 93LC66-I/SN incorporates hardware-level power-on/off protection that disables all programming modes until VCC exceeds 1.4V, and re-enables protection when VCC drops below that threshold. Additionally, it powers up in Erase/Write Disable (EWDS) mode, requiring an explicit EWEN command before any erase or write - ensuring the 93LC66-I/SN remains immune to spurious writes during brown-out or reset sequences.
What is the maximum clock frequency supported by the 93LC66-I/SN?
The 93LC66-I/SN supports a maximum clock frequency of 2 MHz when VCC ≥ 4.5V, and 1 MHz when VCC < 4.5V. These limits are specified in the AC Characteristics table (DS21712C-page 3) and apply to all instruction phases - opcode, address, and data transfer - ensuring reliable timing margin across the full industrial temperature range.
Can the 93LC66-I/SN be used in a shared-data-bus configuration with DI and DO connected together?
The 93LC66-I/SN permits DI and DO sharing only in x16 mode at clock frequencies ≤1 MHz, as stated in Section 2.2. At higher speeds or in x8 mode, bus conflict may occur during the dummy-zero phase of read operations, causing undefined voltage levels on the shared line. For robust designs, separate DI/DO traces are recommended - especially for the 93LC66-I/SN in production systems.
Is the 93LC66-I/SN still recommended for new designs?
No - Microchip explicitly states "Not recommended for new designs" in DS21712C-page 1 and recommends migration to the 93LC66C-I/SN. While the 93LC66-I/SN remains available for legacy support and repair, new projects should use the 93LC66C-I/SN for enhanced ESD performance, tighter AC timing, and extended qualification coverage including AEC-Q100 Grade 3.
93LC66-I/SN Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Microchip Technology
- Series:
- -
- Package/Case:
- 8-SOIC (0.154", 3.90mm Width)
- Packaging:
- Tube
- Product Status:
- Active
- Programmable:
- Verified
- Memory Type:
- Non-Volatile
- Memory Format:
- EEPROM
- Technology:
- EEPROM
- Memory Size:
- 4Kbit
- Memory Organization:
- 512 x 8, 256 x 16
- Memory Interface:
- Microwire
- Clock Frequency:
- 2 MHz
- Write Cycle Time - Word, Page:
- 10ms
- Access Time:
- -
- Voltage - Supply:
- 2.5V ~ 5.5V
- Operating Temperature:
- -40°C ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 8-SOIC
93LC66-I/SN FAQ
1.How can I place an order for 93LC66-I/SN through Aetrix?
Please submit a Request for Quotation (RFQ) for 93LC66-I/SN 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 93LC66-I/SN reliable?
The price and inventory of 93LC66-I/SN are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for 93LC66-I/SN is usually 5 days.
3.What payment methods are accepted for 93LC66-I/SN?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for 93LC66-I/SN transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for 93LC66-I/SN?
93LC66-I/SN orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your 93LC66-I/SN 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 93LC66-I/SN?
For technical support, including 93LC66-I/SN datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your 93LC66-I/SN requirements.
6.How does Aetrix verify that 93LC66-I/SN is sourced from the original manufacturer or authorized distributors?
All 93LC66-I/SN 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 93LC66-I/SN meets industry standards.
7.What is the process for return or replacement of 93LC66-I/SN?
All 93LC66-I/SN units undergo pre-shipment inspection (PSI). If there is an issue with 93LC66-I/SN, 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 93LC66-I/SN part is unused and in its original packaging.
Return procedure for 93LC66-I/SN:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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