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Microchip Technology 93LC66XT/SN
- Part No.:
- 93LC66XT/SN
- Manufacturer:
- Microchip Technology
- Category:
- Memory
- Package:
- 8-SOIC (0.154", 3.90mm Width)
- Datasheet:
-
93LC66XT/SN.pdf
- Description:
- IC EEPROM 4KBIT MICROWIRE 8SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:1,428
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Product details
Overview
93LC66XT/SN from Microchip Technology Inc. is a 4K-bit (512 × 8 or 256 × 16) low-voltage serial EEPROM with Microwire™ interface, supporting single-supply operation down to 2.5V, 1,000,000 erase/write cycles, and >200-year data retention. It features ORG-pin-selectable memory organization and self-timed erase/write cycles, used in embedded system configuration storage and calibration data retention.
For engineers reviewing the 93LC66XT/SN datasheet, 93LC66XT/SN pinout, 93LC66XT/SN application, or 93LC66XT/SN equivalent, key selection considerations include its 3-wire serial interface timing (max 2 MHz at VCC < 4.5V), industrial temperature range (–40°C to +85°C), SOIC-8 rotated pinout, and power-on/off data protection circuitry.
Technical Context
The 93LC66XT/SN implements a synchronous 3-wire Microwire-compatible interface with CS, CLK, and bidirectional DI/DO pins. Its internal logic decodes 8- or 16-bit organization based on the ORG pin state, and supports instruction-set-driven operations including READ, WRITE, ERASE, ERAL, WRAL, EWEN, and EWDS.
It uses self-timed internal programming cycles - typical 4 ms per word for WRITE/ERASE, 8 ms for ERAL, and 16 ms for WRAL - with DO pin providing Ready/Busy status polling during active cycles. Power-up defaults to EWDS mode, requiring explicit EWEN before any programming command.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Memory size | 4 Kbit (512 × 8 or 256 × 16 bits), configurable via ORG pin - enables flexible byte- or word-oriented data storage in constrained firmware environments. |
| Supply voltage | 2.5V to 5.5V - supports direct integration into 3.3V and 5V systems without level-shifting; programming guaranteed down to 2.5V. |
| Interface | 3-wire Microwire™ serial (CS/CLK/DI/DO) - minimal GPIO usage; no SPI mode select or polarity requirements. |
| Endurance & retention | 1,000,000 erase/write cycles and >200 years data retention - suitable for long-life industrial control and metering applications with infrequent but critical updates. |
| Timing (VCC < 4.5V) | Max clock frequency = 1 MHz, TCKH/TCKL ≥ 250 ns - defines minimum MCU clock setup/hold margins for reliable bit-banged or hardware peripheral implementation. |
| Operating temperature | –40°C to +85°C (Industrial grade) - validated for use in automotive body electronics, industrial PLCs, and outdoor IoT edge nodes. |
| Active/standby current | 100 µA typical read current at 2.5V; 3 µA typical standby current at 2.5V - enables battery-backed operation in low-power sensor nodes. |
Pinout & Package
93LC66XT/SN uses the rotated SOIC-8 (SN) package per JEDEC MS-012, with pin 1 at bottom-left when notch faces up. Pin numbering differs from standard SOIC: pin 1 = CS, pin 2 = CLK, pin 3 = DI, pin 4 = DO, pin 5 = VSS, pin 6 = ORG, pin 7 = NU (not utilized), pin 8 = VCC.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| CS (Pin 1) | Chip Select input | Active-high enable; must be held low ≥250 ns between instructions; initiates self-timed programming on falling edge. |
| CLK (Pin 2) | Serial clock input | Synchronizes all data transfers on rising edge; stoppable at any point; not required during auto-erase/write cycles. |
| DI (Pin 3) | Serial data input | Accepts Start bit, opcode, address, and write data; tied high with CS to detect Start condition. |
| DO (Pin 4) | Serial 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 internal logic and I/O; must be low-impedance connection to avoid timing violations. |
| ORG (Pin 6) | Memory organization select | VCC = x16 mode (256 words); VSS = x8 mode (512 bytes); floating allowed only ≤1 MHz in x16 mode. |
| NU (Pin 7) | No-connect terminal | Internally unconnected; must remain unconnected on PCB; no routing or termination required. |
| VCC (Pin 8) | Power supply | 2.5V–5.5V input; internal power-on reset and voltage monitor inhibit programming below 1.4V. |
Key Features
| Feature | Design Value |
|---|---|
| ORG-pin memory configuration | Selects 512×8 or 256×16 organization dynamically at boot - eliminates need for separate part numbers or firmware variants. |
| Self-timed erase/write cycles | Removes external timing dependencies: 4 ms (WRITE/ERASE), 8 ms (ERAL), 16 ms (WRAL) - simplifies host controller software and reduces interrupt latency burden. |
| Power-on/off data protection | Hardware-enforced inhibition of programming below 1.4V - prevents corruption during brown-out or hot-plug events without external supervisor IC. |
| Ready/Busy status via DO pin | Enables non-blocking polling instead of fixed delays - improves system responsiveness and reduces average write latency in multi-device buses. |
| EWEN/EWDS security lock | Explicit enable/disable commands prevent accidental writes - allows safe default (EWDS) state after power-up and deterministic recovery after errors. |
Applications
| Industrial Sensor Calibration | Consumer Appliance Settings |
|---|---|
Use Scenario: Storing factory-trimmed ADC offset/gain coefficients and user-adjusted temperature compensation tables in HVAC controllers. IC Role / Device Role / Timing Role: Nonvolatile configuration register accessed during boot and occasionally updated via service mode. Use Value: Ensures consistent measurement accuracy across product lifetime; leverages 200-year retention and 1M-cycle endurance for field recalibration. |
Use Scenario: Retaining user preferences (cook time, temperature, language) and error logs in microwave ovens and washing machines. IC Role / Device Role / Timing Role: Low-pin-count, low-power parameter store interfaced to 8-bit microcontroller GPIOs. Use Value: Enables 2.5V operation directly from appliance 3.3V rail; 3 µA standby current extends battery backup life during power loss. |
| Automotive Body Control Module | Medical Device Configuration |
Use Scenario: Saving seat/mirror position memory, lighting profiles, and door lock settings in 12V vehicle systems with LDO-regulated 3.3V domains. IC Role / Device Role / Timing Role: Microwire EEPROM integrated into CAN/LIN gateway firmware update path for persistent parameter storage. Use Value: Industrial temperature rating (–40°C to +85°C) ensures reliability under hood conditions; rotated SOIC-8 fits dense PCB layouts. |
Use Scenario: Holding device-specific calibration constants, regulatory compliance flags, and audit trail timestamps in portable glucose meters and infusion pumps. IC Role / Device Role / Timing Role: Secure, tamper-resistant configuration store with hardware write-protection (EWDS default). Use Value: Prevents unauthorized reprogramming via power-cycle resilience and mandatory EWEN command - supports IEC 62304 Class B software safety requirements. |
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 (≥6 kV), improved AC timing margins, and extended 10-year longevity support. | Recommended for new designs; same footprint and instruction set but higher reliability in noisy industrial environments. | Select 93LC66C-I/SN for production releases requiring long-term component availability and robustness beyond legacy 93LC66XT/SN. |
| AT25040B-MAU-1.8 | SPI interface (4-wire), 4 Kbit, 1.8V–5.5V supply, 20 MHz max clock, 1M endurance, SOIC-8 standard pinout. | Requires SPI-capable MCU peripheral; lacks ORG-pin flexibility but offers faster throughput and lower latency. | Choose AT25040B-MAU-1.8 when migrating to SPI-based platforms or needing higher bandwidth; verify pinout compatibility and driver adaptation. |
Compared with 93LC66XT/SN, the 93LC66C-I/SN provides drop-in reliability upgrades without layout changes, while the AT25040B-MAU-1.8 trades Microwire simplicity for SPI speed and broader voltage range - both require validation of firmware command mapping and timing constraints.
Availability
93LC66XT/SN is available at Aetrix Electronics and suitable for industrial sensor calibration, consumer appliance settings, automotive body control modules, and medical device configuration requiring stable component supply over extended production lifecycles.
Supply support for 93LC66XT/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 93LC66XT/SN belongs to Microchip's legacy 93LC serial EEPROM family, designed specifically for cost-sensitive, low-pin-count embedded systems requiring simple, robust nonvolatile storage with minimal MCU resource usage.
FAQ
What is the memory organization of 93LC66XT/SN and how is it selected?
The 93LC66XT/SN supports two memory organizations: 512 × 8 bits (x8) or 256 × 16 bits (x16), selected by the logic level on the ORG pin. When ORG is tied to VSS (ground), the x8 mode is active; when tied to VCC, the x16 mode is active. The 93LC66XT/SN datasheet confirms this behavior is valid across the full operating voltage and temperature range, and floating ORG is permitted only at clock frequencies ≤1 MHz in x16 mode.
Does 93LC66XT/SN support true SPI communication?
No, 93LC66XT/SN does not support standard SPI. It uses a proprietary 3-wire Microwire™ interface (CS/CLK/DI/DO) with specific instruction encoding, start-bit detection, and status reporting via DO. Unlike SPI, it lacks dedicated MISO/MOSI lines and requires precise clock timing per instruction cycle count (e.g., 27 clocks for READ in x16 mode). The 93LC66XT/SN cannot be substituted with SPI EEPROMs without firmware redesign.
What is the purpose of the NU pin on 93LC66XT/SN?
Pin 7 of the 93LC66XT/SN is labeled NU (Not Utilized) and is internally unconnected. It must remain unconnected on the PCB - no routing, pull-up, pull-down, or capacitive loading is permitted. This pin exists due to the rotated SOIC-8 (SN) package layout and has no electrical function; connecting it may cause undefined behavior or damage.
How does 93LC66XT/SN protect against accidental writes during power transitions?
The 93LC66XT/SN incorporates hardware power-on/power-off protection that inhibits all programming operations (ERASE, WRITE, EWEN) until VCC rises above 1.4V, and re-enables inhibition when VCC falls below 1.4V. Additionally, it powers up in EWDS (Erase/Write Disable) mode, requiring an explicit EWEN command before any programming instruction executes - ensuring 93LC66XT/SN remains write-protected unless intentionally enabled by firmware.
Is 93LC66XT/SN pin-compatible with standard SOIC-8 packages?
No, 93LC66XT/SN uses the rotated SOIC-8 (SN) package, where pin 1 is CS (not VCC or NC), and pin order differs from JEDEC-standard SOIC-8. Standard SOIC-8 footprints will misalign: e.g., 93LC66XT/SN pin 8 = VCC, but standard SOIC-8 pin 8 = NC or VCC depending on orientation. The 93LC66XT/SN requires the rotated layout defined in Microchip drawing C04-057; using a standard SOIC-8 footprint will result in incorrect connections and functional failure.
93LC66XT/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:
- Obsolete
- 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
93LC66XT/SN FAQ
1.How can I place an order for 93LC66XT/SN through Aetrix?
Please submit a Request for Quotation (RFQ) for 93LC66XT/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/SN reliable?
The price and inventory of 93LC66XT/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/SN is usually 5 days.
3.What payment methods are accepted for 93LC66XT/SN?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for 93LC66XT/SN transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for 93LC66XT/SN?
93LC66XT/SN orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your 93LC66XT/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/SN?
For technical support, including 93LC66XT/SN datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your 93LC66XT/SN requirements.
6.How does Aetrix verify that 93LC66XT/SN is sourced from the original manufacturer or authorized distributors?
All 93LC66XT/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/SN meets industry standards.
7.What is the process for return or replacement of 93LC66XT/SN?
All 93LC66XT/SN units undergo pre-shipment inspection (PSI). If there is an issue with 93LC66XT/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/SN part is unused and in its original packaging.
Return procedure for 93LC66XT/SN:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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