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Microchip Technology 93LC66AXT/SN
- Part No.:
- 93LC66AXT/SN
- Manufacturer:
- Microchip Technology
- Category:
- Memory
- Package:
- 8-SOIC (0.154", 3.90mm Width)
- Datasheet:
-
93LC66AXT/SN.pdf
- Description:
- IC EEPROM 4KBIT MICROWIRE 8SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:2,131
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Product details
Overview
93LC66AXT/SN from Microchip Technology Inc. is a 4 Kbit (512 × 8-bit) low-voltage serial EEPROM with Microwire-compatible 3-wire interface, 2.5–5.5 V supply range, and industrial temperature grade (–40°C to +85°C). It features self-timed erase/write cycles, automatic ERAL before WRAL, power-on/off data protection, and Ready/Busy status signaling via DO pin - used in embedded system configuration storage and calibration data retention.
For engineers reviewing the 93LC66AXT/SN datasheet, 93LC66AXT/SN pinout, 93LC66AXT/SN application, or 93LC66AXT/SN equivalent, key selection criteria include its dedicated 8-bit organization (no ORG pin), SOIC-8 package, 1 million erase/write endurance, >200-year data retention, and compatibility with microcontroller SPI-like serial masters requiring minimal I/O resources.
Technical Context
The 93LC66AXT/SN implements a synchronous serial interface using CS, CLK, and DI/DO lines with start-bit detection and opcode-based command decoding. Its memory array is organized as 512 words × 8 bits, fixed by design (no ORG pin), eliminating external configuration logic required for x8/x16 variants.
It supports full instruction set including READ, WRITE, ERASE, ERAL, WRAL, EWEN, and EWDS, with all programming operations auto-erasing prior to write. Status polling via DO pin during TCSL ≥250 ns enables non-blocking firmware control without fixed delay loops.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Memory size | 4 Kbit (512 × 8-bit); fixed x8 organization - no ORG pin needed, simplifying PCB layout and firmware initialization. |
| VCC range | 2.5 V to 5.5 V; supports direct connection to 3.3 V or 5 V MCU I/O rails without level shifting. |
| Endurance | 1,000,000 erase/write cycles; sufficient for field-updatable calibration tables updated daily over 27 years. |
| Data retention | >200 years at 25°C; ensures long-term reliability in unpowered storage of device identity or security keys. |
| Write cycle time | 6 ms typical (TWC); deterministic timing enables precise timeout handling in real-time firmware. |
| Interface | Microwire-compatible 3-wire serial (CS/CLK/DI/DO); uses standard GPIO bit-banging or hardware SPI in 3-wire mode. |
| Temp range | Industrial: –40°C to +85°C; qualified for use in industrial controllers, metering, and automotive body electronics. |
Pinout & Package
93LC66AXT/SN is packaged in 8-lead SOIC (SN), with pin 1 marked by laser dot. All pins are electrically defined per Microchip DS21795E; ORG pin is NC (no internal connection) on 'A' devices.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 (CS) | Chip Select | Active-high enable; must be held low ≥250 ns between commands; falling edge initiates self-timed write on 93LC66A/B/C. |
| 2 (CLK) | Serial Clock | Rising-edge synchronized I/O; clock can pause mid-transfer; no clocks required during auto-erase/write cycle. |
| 3 (DI) | Data Input | Accepts start bit, opcode, address, and data; high-impedance when CS low; requires pull-down if shared with DO. |
| 4 (DO) | Data Output / Status | Outputs read data or Ready/Busy (low = busy); enters High-Z on CS falling edge; status valid only after TCSL ≥250 ns. |
| 5 (VSS) | Ground | Reference for all I/O and internal circuitry; must be low-impedance connection to minimize noise coupling. |
| 6 (NC) | No Connect | Internally unconnected; must be left floating or tied to VSS per layout best practice - no routing required. |
| 7 (NC) | No Connect | Same as pin 6; dual NC pins reduce crosstalk risk in SOIC layout; no electrical function. |
| 8 (VCC) | Power Supply | 2.5–5.5 V supply; includes internal POR at 1.5 V threshold; decoupling capacitor (0.1 µF) required near pin. |
Key Features
| Feature | Design Value |
|---|---|
| Self-timed erase/write | Eliminates need for external timing control or firmware delay loops - write completes in ≤6 ms with automatic erase. |
| Automatic ERAL before WRAL | Ensures full-array write integrity without separate erase command - reduces firmware complexity and command sequence errors. |
| Power-on/off data protection | Hardware-level inhibition below 1.5 V VCC prevents corruption during brown-out or hot-plug events. |
| Ready/Busy status on DO | Enables polling-based operation without fixed delays - improves system responsiveness and avoids unnecessary CPU wait states. |
| Sequential read mode | Allows continuous read across multiple addresses with single CS assertion - reduces transaction overhead for block reads. |
Applications
| Industrial Sensor Calibration | Embedded System Configuration |
|---|---|
Use Scenario: Storing factory-calibrated sensor offset/gain coefficients in programmable logic controllers and environmental monitors. IC Role / Device Role / Timing Role: Nonvolatile parameter storage accessed at boot and during field recalibration; retains values across power cycles. Use Value: Enables plug-and-play sensor replacement with pre-loaded calibration data, reducing field service time and eliminating manual trim adjustments. | Use Scenario: Holding user-configurable settings (e.g., display brightness, communication baud rate, alarm thresholds) in medical diagnostic equipment. IC Role / Device Role / Timing Role: Serial configuration memory interfaced to MCU GPIOs; accessed infrequently but must survive 10+ years of operation. Use Value: Provides reliable, low-pin-count storage for up to 512 bytes of persistent settings without requiring battery backup or larger flash ICs. |
| Automotive Body Control Module | Consumer Appliance State Memory |
Use Scenario: Saving seat/mirror position memory and lighting preferences in 12 V automotive systems operating across –40°C to +85°C. IC Role / Device Role / Timing Role: Industrial-grade EEPROM interfaced to 5 V tolerant MCU peripherals; withstands load-dump transients via robust VCC monitoring. Use Value: Delivers AEC-Q100-aligned reliability (via E-temp variant family) while maintaining pin and software compatibility with cost-sensitive designs. | Use Scenario: Retaining cooking program history and child-lock state in smart ovens and washing machines after power loss. IC Role / Device Role / Timing Role: Low-power serial memory accessed during startup and mode transitions; draws ≤1 µA in standby. Use Value: Supports energy-efficient design with <1 µA ICCS, extending standby battery life in AC-powered appliances with backup RTC circuits. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar serial EEPROM applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| 93LC66BXT/SN | 16-bit organization (256 × 16), same VCC/temp range; requires ORG pin tied to VSS for x8 emulation - not pin-compatible due to ORG pin presence. | Used where wider data path reduces transaction count; unsuitable for legacy x8-only firmware without modification. | Select only if system firmware supports 16-bit addressing and layout accommodates ORG pin routing. |
| AT25040B-MAU-1.8 | SPI interface (4-wire), 4 Kbit (512 × 8), 1.8–5.5 V, same endurance/retention; lacks Ready/Busy pin - relies on WIP flag polling via STATUS register. | Requires SPI master support and additional STATUS read overhead; better suited for systems already using SPI peripherals. | Choose when migrating from Microwire to SPI infrastructure or when 1.8 V minimum VCC is mandatory. |
Compared with 93LC66BXT/SN, the 93LC66AXT/SN eliminates ORG pin dependency and guarantees x8 timing behavior; versus AT25040B-MAU-1.8, it offers simpler status polling via DO pin but requires bit-banged Microwire instead of hardware SPI.
Availability
93LC66AXT/SN is available at Aetrix Electronics and suitable for industrial sensor calibration, embedded system configuration, and automotive body control modules requiring stable component supply, long-lifecycle support, and RoHS-compliant packaging.
Supply support for 93LC66AXT/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 components, and memory solutions, headquartered in Chandler, Arizona.
The 93LC66A belongs to Microchip's legacy 93XX serial EEPROM product line, designed specifically for cost-sensitive, low-pin-count nonvolatile storage in resource-constrained embedded systems.
FAQ
What is the memory organization of the 93LC66AXT/SN?
The 93LC66AXT/SN has a fixed 512 × 8-bit (4 Kbit) organization with no ORG pin - unlike 'C' variants, it does not support x16 mode. This eliminates external configuration logic and ensures deterministic 8-bit data transfers. The absence of ORG simplifies PCB routing and firmware driver development for legacy Microwire interfaces.
Does the 93LC66AXT/SN require an external pull-up resistor on the DO pin?
No external pull-up is required on the DO pin of the 93LC66AXT/SN. The device drives DO actively during READ and Ready/Busy status reporting. However, if DI and DO are shorted (common bus configuration), a series resistor (typically 1–10 kΩ) is recommended to prevent bus contention during the dummy zero phase of READ operations.
What is the minimum VCC voltage that enables reliable write operations for the 93LC66AXT/SN?
The 93LC66AXT/SN requires VCC ≥2.5 V for guaranteed write operation, with internal power-on reset (POR) activating at ~1.5 V to inhibit writes during brown-out. Below 2.5 V, the device remains in read-only mode and will not accept ERASE or WRITE commands - ensuring data integrity during power ramp-up or dropout.
How is the Ready/Busy status signaled on the 93LC66AXT/SN?
The 93LC66AXT/SN signals Ready/Busy status on the DO pin: DO = low indicates ongoing erase/write; DO = high indicates completion. Status is only valid after CS is brought high for ≥250 ns (TCSL) following command initiation. Issuing a new Start bit then lowering CS clears the status flag, enabling immediate re-polling.
Is the 93LC66AXT/SN compatible with standard SPI hardware peripherals?
The 93LC66AXT/SN is Microwire-compatible, not SPI-compatible - it uses a 3-wire interface (CS/CLK/DI/DO) with start-bit detection and no MISO/MOSI separation. While it can be driven by bit-banged GPIOs or SPI peripherals configured in 3-wire mode, it does not support SPI mode 0–3 clock polarity/phase conventions or native SPI status registers like the AT25xxx series.
93LC66AXT/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
- Memory Interface:
- Microwire
- Clock Frequency:
- 2 MHz
- Write Cycle Time - Word, Page:
- 6ms
- 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
93LC66AXT/SN FAQ
1.How can I place an order for 93LC66AXT/SN through Aetrix?
Please submit a Request for Quotation (RFQ) for 93LC66AXT/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 93LC66AXT/SN reliable?
The price and inventory of 93LC66AXT/SN are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for 93LC66AXT/SN is usually 5 days.
3.What payment methods are accepted for 93LC66AXT/SN?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for 93LC66AXT/SN transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for 93LC66AXT/SN?
93LC66AXT/SN orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your 93LC66AXT/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 93LC66AXT/SN?
For technical support, including 93LC66AXT/SN datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your 93LC66AXT/SN requirements.
6.How does Aetrix verify that 93LC66AXT/SN is sourced from the original manufacturer or authorized distributors?
All 93LC66AXT/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 93LC66AXT/SN meets industry standards.
7.What is the process for return or replacement of 93LC66AXT/SN?
All 93LC66AXT/SN units undergo pre-shipment inspection (PSI). If there is an issue with 93LC66AXT/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 93LC66AXT/SN part is unused and in its original packaging.
Return procedure for 93LC66AXT/SN:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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