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Microchip Technology 93LC66/SN
- Part No.:
- 93LC66/SN
- Manufacturer:
- Microchip Technology
- Category:
- Memory
- Package:
- 8-SOIC (0.154", 3.90mm Width)
- Datasheet:
-
93LC66/SN.pdf
- Description:
- IC EEPROM 4KBIT MICROWIRE 8SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:3,552
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Product details
Overview
93LC66/SN from Microchip Technology Inc. is a 4 Kbit (512 × 8 or 256 × 16) low-voltage serial EEPROM with Microwire™ interface, ORG-pin-selectable memory organization, and industrial temperature range (–40°C to +85°C). It operates down to 2.5 V, features self-timed erase/write cycles, 1 million endurance cycles, and >200-year data retention. Used for configuration storage in embedded controllers and power management systems.
For engineers reviewing the 93LC66/SN datasheet, 93LC66/SN pinout, 93LC66/SN application, or 93LC66/SN equivalent, key selection criteria include its 3-wire serial interface timing (max 2 MHz at VCC < 4.5 V), dual x8/x16 organization flexibility, power-on/off data protection, and SOIC-8 (SN) package compatibility with legacy board layouts.
Technical Context
The 93LC66/SN implements a synchronous 3-wire Microwire-compatible interface with CS, CLK, and bidirectional DI/DO lines. Its internal logic decodes 10-bit addresses (x8 mode) or 8-bit addresses (x16 mode) based on ORG pin state, supporting READ, WRITE, ERASE, ERAL, WRAL, EWEN, and EWDS instructions with clocked opcode/address/data sequences.
It uses CMOS nonvolatile floating-gate technology with automatic pre-erase (ERAL before WRAL), device status signaling via DO pin during programming, and power-supply monitoring circuitry that inhibits write operations below 1.4 V. All erase/write cycles are fully self-timed and require no external timing control.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Memory size | 4 Kbit (512 × 8 or 256 × 16 bits), selectable via ORG pin - enables flexible byte- or word-oriented firmware storage |
| Supply voltage | 2.5 V to 5.5 V - supports direct interfacing with 2.5 V, 3.3 V, and 5 V microcontrollers without level shifters |
| Interface | 3-wire Microwire™ serial (CS, CLK, DI/DO) - minimal GPIO usage; compatible with legacy PIC® and 8051-based designs |
| Write endurance | 1,000,000 erase/write cycles - ensures long-term reliability in frequent configuration update applications |
| Data retention | >200 years at 25°C - suitable for unattended industrial equipment requiring decades of nonvolatile storage integrity |
| Operating temperature | –40°C to +85°C (Industrial grade) - validated for use in automotive body control modules and industrial PLC I/O cards |
| Max clock frequency | 2 MHz at VCC < 4.5 V - defines maximum instruction throughput; limits burst read/write speed in low-voltage operation |
Pinout & Package
8-pin SOIC (SN) package per JEDEC MS-012, 150-mil width, surface-mount compatible. Pin 1 marked by notch or dot; pin 1 is CS.
| 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 programming on falling edge |
| CLK (Pin 2) | Serial Clock | Synchronizes all data transfers; rising-edge sampling of DI and DO; stoppable mid-sequence without corruption |
| DI (Pin 3) | Data Input | Receives Start bit, opcode, address, and write data; shares net with DO only if bus conflict mitigation is implemented |
| 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 polling |
| VSS (Pin 5) | Ground | Reference return path for all digital and analog functions; must be low-impedance connection to system GND plane |
| ORG (Pin 6) | Organization Select | Tied to VCC for x16 mode (256 words), VSS for x8 mode (512 bytes); floating allowed only ≤1 MHz in x16 mode |
| NU (Pin 7) | No Connect | Internally unconnected; must be left floating or tied to VSS/VCC per PCB layout best practices - no functional role |
| VCC (Pin 8) | Power Supply | 2.5–5.5 V supply; includes internal voltage monitor that blocks writes below 1.4 V during power-up/down transitions |
Key Features
| Feature | Design Value |
|---|---|
| ORG-pin memory configuration | Hardware-selectable x8 or x16 organization eliminates need for software rework when migrating between byte- and word-addressed firmware layouts |
| Self-timed erase/write | Eliminates external timing components and host CPU wait-state management - WRAL completes in 16 ms typical, independent of clock rate |
| Power-on/off data protection | Hardware-enforced write inhibition below 1.4 V prevents corruption during brown-out or cold-start conditions without firmware intervention |
| Sequential read mode | Enables continuous block reads with single CS assertion - reduces transaction overhead for loading multi-byte calibration tables |
| Status polling via DO | Allows real-time readiness verification during programming without dedicated status registers or interrupts - simplifies driver implementation |
Applications
| Industrial Sensor Calibration | Embedded Controller Configuration |
|---|---|
|
Use Scenario: Storing factory-trimmed sensor offset/gain coefficients and linearization tables in environmental monitoring nodes. IC Role / Device Role / Timing Role: Nonvolatile configuration storage with infrequent updates and guaranteed data integrity over 10+ years of field operation. Use Value: Eliminates need for external backup batteries or supercapacitors; >200-year retention ensures calibration persistence across product lifecycle. |
Use Scenario: Holding boot-time configuration parameters (baud rate, I/O mapping, watchdog timeout) for microcontroller-based motor drives. IC Role / Device Role / Timing Role: Serial parameter store accessed during early boot sequence via simple GPIO bit-banging or hardware SPI/Microwire peripheral. Use Value: Reduces BOM count versus parallel EEPROM; 2.5 V operation allows direct interface with low-power MCUs without level translation. |
| Power Management Unit Settings | Legacy Industrial PLC I/O Modules |
|
Use Scenario: Saving user-defined voltage/current thresholds and fault response modes in AC/DC power supplies with digital control. IC Role / Device Role / Timing Role: Secure, low-pin-count NVM for safety-critical settings updated only during maintenance mode. Use Value: Built-in EWEN/EWDS commands prevent accidental writes; 1M endurance supports thousands of commissioning cycles over product life. |
Use Scenario: Retaining module identification, channel calibration, and diagnostic history in DIN-rail mounted I/O expansion units. IC Role / Device Role / Timing Role: Drop-in replacement for obsolete 93LC66-I/P in existing SOIC footprints; same pinout and instruction set as legacy designs. Use Value: SN package matches standard 150-mil SOIC land patterns; industrial temp rating ensures reliability in unventilated control cabinets. |
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 | Enhanced version with improved ESD rating (≥4 kV HBM), tighter tPD spec (400 ns max), and extended VCC range (1.8–5.5 V) | Required for new designs targeting IEC 61000-4-2 compliance or 1.8 V host interfaces | Select 93LC66C-I/SN for new designs; 93LC66/SN remains valid for legacy repair and continuity builds |
| AT25040B-MAU-1.8 | 4 Kbit SPI interface (4-wire), 1.8–5.5 V operation, 20 MHz max clock, 100-year retention, no ORG pin - fixed 512 × 8 organization | Used where higher-speed SPI is available and x16 mode is unnecessary; lacks hardware organization select | Choose AT25040B-MAU-1.8 only if migrating to SPI infrastructure and accepting loss of x16 flexibility |
Compared with 93LC66C-I/SN, the 93LC66/SN offers identical pinout and instruction set but lacks 1.8 V support and enhanced ESD robustness; compared with AT25040B-MAU-1.8, it provides ORG-selectable organization and Microwire compatibility but lower maximum clock speed and no SPI-native interface.
Availability
93LC66/SN is available at Aetrix Electronics and suitable for industrial sensor calibration, embedded controller configuration, and power management unit settings requiring stable component supply and long-term obsolescence management.
Supply support for 93LC66/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/SN belongs to Microchip's legacy 93LC serial EEPROM family, designed specifically for cost-sensitive, low-pin-count nonvolatile storage in industrial and automotive subsystems where Microwire interface compatibility and long data retention are critical.
FAQ
What is the memory organization of 93LC66/SN and how is it selected?
The 93LC66/SN supports two memory organizations: 512 × 8 bits (x8) or 256 × 16 bits (x16), selected by the logic level applied to the ORG pin. When ORG is tied to VSS, x8 mode is active; when tied to VCC, x16 mode is active. The 93LC66/SN datasheet specifies that ORG may be floated only at clock frequencies ≤1 MHz in x16 mode. This hardware-selectable configuration allows one device to serve multiple firmware architectures without redesign.
Does 93LC66/SN support true SPI communication?
No, the 93LC66/SN implements a 3-wire Microwire™ interface (CS, CLK, DI/DO), not standard 4-wire SPI. It lacks separate SI/SO lines and uses a shared bidirectional data line with start-bit detection. While functionally similar for basic read/write, it does not support SPI mode settings (CPOL/CPHA) or daisy-chaining. The 93LC66/SN requires host-side bit-banging or Microwire-compatible peripheral support - not generic SPI hardware.
What is the purpose of the NU pin on 93LC66/SN?
Pin 7 of the 93LC66/SN is labeled NU (No Connect) in the official pin function table and is internally unconnected. It must be left floating on the PCB; tying it to VCC or VSS has no functional effect but may improve mechanical stability or reduce noise coupling in high-density layouts. The 93LC66/SN datasheet explicitly states NU has no electrical role and should not be used as a ground or supply tie point.
How does the 93LC66/SN indicate readiness after a write operation?
The 93LC66/SN signals readiness via the DO pin: during an erase or write cycle, DO outputs a low (busy) signal until completion, then transitions high (ready). To poll status, CS must be brought high for ≥250 ns after the initial CS low pulse, and DO must be read while CS is high. A pull-up resistor is required on DO to ensure valid high-level detection. This mechanism applies identically across all 93LC66/SN programming operations including WRAL and ERAL.
Is 93LC66/SN suitable for new designs?
No - Microchip explicitly marks the 93LC66/SN as "Not recommended for new designs" in the datasheet, advising migration to the enhanced 93LC66C-I/SN variant. The 93LC66/SN remains fully supported for legacy repair, continuity builds, and obsolescence management, but new projects should use 93LC66C-I/SN for improved 1.8 V operation, higher ESD immunity, and extended qualification. Aetrix Electronics maintains inventory of 93LC66/SN specifically for these legacy-support scenarios.
93LC66/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:
- Not 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:
- 0°C ~ 70°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 8-SOIC
93LC66/SN FAQ
1.How can I place an order for 93LC66/SN through Aetrix?
Please submit a Request for Quotation (RFQ) for 93LC66/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/SN reliable?
The price and inventory of 93LC66/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/SN is usually 5 days.
3.What payment methods are accepted for 93LC66/SN?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for 93LC66/SN transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for 93LC66/SN?
93LC66/SN orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your 93LC66/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/SN?
For technical support, including 93LC66/SN datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your 93LC66/SN requirements.
6.How does Aetrix verify that 93LC66/SN is sourced from the original manufacturer or authorized distributors?
All 93LC66/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/SN meets industry standards.
7.What is the process for return or replacement of 93LC66/SN?
All 93LC66/SN units undergo pre-shipment inspection (PSI). If there is an issue with 93LC66/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/SN part is unused and in its original packaging.
Return procedure for 93LC66/SN:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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