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Microchip Technology 93LC66XT-I/SN
- Part No.:
- 93LC66XT-I/SN
- Manufacturer:
- Microchip Technology
- Category:
- Memory
- Package:
- 8-SOIC (0.154", 3.90mm Width)
- Datasheet:
-
93LC66XT-I/SN.pdf
- Description:
- IC EEPROM 4KBIT MICROWIRE 8SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:3,806
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Product details
Overview
93LC66XT-I/SN from Microchip Technology Inc. is a 4K-bit (512 × 8 or 256 × 16) low-voltage serial EEPROM with Microwire™ interface, ORG-pin configurable memory organization, and industrial temperature range (–40°C to +85°C). It operates down to 2.5V, features self-timed erase/write cycles, 1 million endurance cycles, and >200-year data retention - used for parameter storage in embedded controllers, sensor calibration, and power management systems.
For engineers reviewing the 93LC66XT-I/SN datasheet, 93LC66XT-I/SN pinout, 93LC66XT-I/SN application, or 93LC66XT-I/SN equivalent, key selection considerations include its 3-wire serial interface timing (max 2 MHz at VCC < 4.5V), standby current of 3 µA at 2.5V, programmable x8/x16 organization via ORG pin, and SOIC-8 package compatibility with legacy 93LC-series designs.
Technical Context
The 93LC66XT-I/SN implements a synchronous 3-wire Microwire-compatible interface (CS/CLK/DI/DO) with start-bit detection and opcode-driven command set. Memory organization is dynamically selected by the ORG pin: logic high enables 256 × 16-bit mode; logic low selects 512 × 8-bit mode - both supported across the full industrial temperature range.
It integrates on-chip power-on/off protection that inhibits programming below 1.4V, plus EWEN/EWDS commands for explicit write-enable control. All erase and write operations (including ERAL and WRAL) are self-timed, with DO pin providing real-time Ready/Busy status during active cycles - eliminating need for external timing delays.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Memory Size | 4 Kbit (512 × 8 or 256 × 16), selectable via ORG pin - enables flexible byte- or word-oriented data storage without firmware changes. |
| Supply Voltage | 2.5V to 5.5V - supports direct integration into 3.3V and 5V systems without level-shifting. |
| Interface | Microwire™ 3-wire serial (CS, CLK, DI, DO) - minimal GPIO usage; compatible with legacy microcontrollers lacking SPI hardware. |
| Endurance | 1,000,000 erase/write cycles - suitable for frequently updated configuration or calibration data. |
| Data Retention | >200 years at 25°C - ensures long-term reliability in unattended or maintenance-free applications. |
| Standby Current | 3 µA at 2.5V - critical for battery-powered devices requiring ultra-low quiescent power. |
| Operating Temp | –40°C to +85°C - qualified for industrial control, automotive body electronics, and outdoor equipment. |
Pinout & Package
8-pin SOIC (SN) package per JEDEC MS-012, 150-mil width, surface-mount compatible. Pin 1 marked with dot; pin 1 is CS (Chip Select).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| CS (Pin 1) | Chip Select | Active-high enable; must be held low ≥250 ns between instructions to reset internal state and prevent spurious commands. |
| CLK (Pin 2) | Serial Clock | Synchronizes all data transfers; rising edge clocks in opcode/address/data; stops/resumes freely without corruption. |
| DI (Pin 3) | Data Input | Receives start bit, instruction opcodes, addresses, and write data; shares no internal pull-up/down. |
| DO (Pin 4) | Data Output / Status | Outputs read data or Ready/Busy status (low = busy); high-Z when inactive - requires external pull-up for reliable status polling. |
| VSS (Pin 5) | Ground | Reference return path for all signals; must be low-impedance connection to minimize noise coupling. |
| ORG (Pin 6) | Organization Select | Logic high → 256×16 mode; logic low → 512×8 mode; floating allowed only ≤1 MHz in x16 mode. |
| NU (Pin 7) | No Connect | Internally unconnected; must remain unconnected on PCB - no routing or termination required. |
| VCC (Pin 8) | Power Supply | 2.5V–5.5V input; includes internal power-on reset and voltage monitor to block writes below 1.4V. |
Key Features
| Feature | Design Value |
|---|---|
| Self-timed erase/write | Eliminates need for external timing circuitry or software delay loops - WRAL completes in 16 ms typical, independent of host clock speed. |
| Auto-erase before write | Ensures data integrity: each WRITE automatically erases target location first - no separate ERASE command needed for single-word updates. |
| Power-on/off data protection | Hardware-enforced write inhibition below 1.4V prevents corruption during brown-out or hot-plug events - no firmware supervision required. |
| Sequential read mode | Enables burst reads across consecutive addresses with single CS assertion - reduces transaction overhead for multi-byte parameter blocks. |
| EWEN/EWDS security | Explicit enable/disable commands prevent accidental writes; device powers up in EWDS state - intentional programming requires deliberate EWEN sequence. |
Applications
| Industrial Sensor Calibration | Embedded System Configuration |
|---|---|
Use Scenario: Storing factory-calibrated offset/gain coefficients for analog sensors in PLC I/O modules. IC Role / Device Role / Timing Role: Nonvolatile parameter storage with infrequent updates but guaranteed retention over 10+ years of field operation. Use Value: Enables one-time calibration at manufacturing; eliminates need for recalibration during service life - reducing maintenance cost and downtime. | Use Scenario: Holding boot-time configuration flags (e.g., UART baud rate, display brightness, network MAC address) in medical infusion pumps. IC Role / Device Role / Timing Role: Low-power, tamper-resistant settings register accessed early in boot sequence before main MCU initializes peripherals. Use Value: Maintains user preferences and safety-critical defaults across power cycles - meets IEC 62304 Class B software requirements for persistent data integrity. |
| Power Management Unit (PMU) | Consumer Appliance Control |
Use Scenario: Recording last-known operating state (voltage thresholds, fault counters, thermal history) in uninterruptible power supplies (UPS). IC Role / Device Role / Timing Role: High-reliability event logger interfaced directly to PMU's supervisor IC via Microwire - survives AC loss without backup capacitor. Use Value: Supports root-cause analysis after shutdowns; 1M-cycle endurance accommodates daily logging without wear-out concerns. | Use Scenario: Storing user-programmed cooking profiles (time/temp sequences) in smart ovens with touch interface. IC Role / Device Role / Timing Role: Parameter store accessible by 8-bit MCU with limited GPIO; x8/x16 flexibility matches recipe data structure (byte-addressed timers vs. word-addressed temp setpoints). Use Value: Enables rich feature set without upgrading to larger MCU - leverages existing 3-wire interface and reduces BOM cost versus SPI EEPROM alternatives. |
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 successor with enhanced ESD rating (8 kV HBM vs. 4 kV), same SOIC-8 package and instruction set. | Recommended for new designs requiring higher robustness in handling-sensitive environments. | Select 93LC66C-I/SN when designing for production beyond 2025; 93LC66XT-I/SN remains valid for legacy repair or continuity builds. |
| AT25040B-MAHL-T | 4-Kbit SPI EEPROM (not Microwire), 2.5–5.5V, SOIC-8, but requires 4-wire interface (CS/SCK/MOSI/MISO) and different command protocol. | Requires firmware rework for clock/data line mapping and instruction translation; no ORG-pin organization flexibility. | Choose only if migrating to SPI-based architecture; not drop-in replaceable due to interface and protocol mismatch. |
Compared with 93LC66C-I/SN, the 93LC66XT-I/SN offers identical functionality and pinout but lacks the enhanced ESD protection and newer qualification - making it suitable for cost-sensitive legacy replacements. Versus AT25040B-MAHL-T, it preserves Microwire compatibility and ORG-pin configurability but requires no SPI peripheral investment.
Availability
93LC66XT-I/SN is available at Aetrix Electronics and suitable for industrial sensor calibration, embedded system configuration, and power management unit applications requiring stable component supply and long-term obsolescence support.
Supply support for 93LC66XT-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 microcontroller, analog, and Flash-IP solutions, headquartered in Chandler, Arizona, with global design and manufacturing operations.
The 93LC66XT-I/SN belongs to Microchip's legacy 93LC serial EEPROM family, designed specifically for cost-sensitive, low-pin-count embedded systems needing simple, robust nonvolatile storage without SPI hardware dependency.
FAQ
What is the maximum clock frequency supported by the 93LC66XT-I/SN?
The 93LC66XT-I/SN supports up to 2 MHz clock frequency when VCC ≥ 4.5V, and 1 MHz when VCC < 4.5V. These limits are defined in the AC Characteristics table (DS21712C, page 3) and ensure reliable setup/hold timing for DI and DO signals under worst-case voltage and temperature conditions. Exceeding these frequencies may cause command misreads or data corruption.
How does the ORG pin affect memory organization in the 93LC66XT-I/SN?
The ORG pin on the 93LC66XT-I/SN selects between two memory configurations: tied to VCC enables 256 × 16-bit (x16) mode; tied to VSS enables 512 × 8-bit (x8) mode. This selection determines address width and data bus width for READ/WRITE operations - confirmed in Tables 1-5 and 1-6 of DS21712C. Floating ORG is permitted only at ≤1 MHz in x16 mode.
Does the 93LC66XT-I/SN require external pull-up resistors on its I/O pins?
Yes - the DO pin requires an external pull-up resistor (typically 4.7–10 kΩ to VCC) to reliably detect the Ready/Busy status (high = ready, low = busy) and to ensure proper high-Z release. CS, CLK, and DI have no internal pull-ups; external pull-downs may be needed depending on host controller drive strength and noise environment - per Functional Description section 2.4 and 2.6.
What is the write cycle time for a single word in the 93LC66XT-I/SN?
A single-word WRITE cycle in the 93LC66XT-I/SN takes 4 ms typical (10 ms max) at VCC = 5V ±10%, as specified in AC Characteristic TWC (DS21712C, page 3). This includes automatic pre-erase and programming - no separate ERASE command is needed. The DO pin provides real-time status during this interval, allowing host polling instead of fixed delays.
Is the 93LC66XT-I/SN RoHS compliant and lead-free?
Yes - the 93LC66XT-I/SN uses a Pb-free JEDEC-compliant Matte Tin (Sn) finish, as stated in Packaging Information (DS21712C, page 11). The "SN" package designation confirms compliance with JEDEC MS-012 and RoHS Directive 2011/65/EU. Full compliance documentation is available via Microchip's packaging specification portal.
93LC66XT-I/SN Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Microchip Technology
- Series:
- -
- Package/Case:
- 8-SOIC (0.154", 3.90mm Width)
- Packaging:
- Tape & Reel (TR)
- 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:
- -40°C ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 8-SOIC
93LC66XT-I/SN FAQ
1.How can I place an order for 93LC66XT-I/SN through Aetrix?
Please submit a Request for Quotation (RFQ) for 93LC66XT-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 93LC66XT-I/SN reliable?
The price and inventory of 93LC66XT-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 93LC66XT-I/SN is usually 5 days.
3.What payment methods are accepted for 93LC66XT-I/SN?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for 93LC66XT-I/SN transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for 93LC66XT-I/SN?
93LC66XT-I/SN orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your 93LC66XT-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 93LC66XT-I/SN?
For technical support, including 93LC66XT-I/SN datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your 93LC66XT-I/SN requirements.
6.How does Aetrix verify that 93LC66XT-I/SN is sourced from the original manufacturer or authorized distributors?
All 93LC66XT-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 93LC66XT-I/SN meets industry standards.
7.What is the process for return or replacement of 93LC66XT-I/SN?
All 93LC66XT-I/SN units undergo pre-shipment inspection (PSI). If there is an issue with 93LC66XT-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 93LC66XT-I/SN part is unused and in its original packaging.
Return procedure for 93LC66XT-I/SN:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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