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Microchip Technology 93LC66AX-I/SN
- Part No.:
- 93LC66AX-I/SN
- Manufacturer:
- Microchip Technology
- Category:
- Memory
- Package:
- 8-SOIC (0.154", 3.90mm Width)
- Datasheet:
-
93LC66AX-I/SN.pdf
- Description:
- IC EEPROM 4KBIT MICROWIRE 8SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:1,612
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Product details
Overview
93LC66AX-I/SN from Microchip Technology Inc. is a 4 Kbit low-voltage serial EEPROM with 512 × 8-bit organization, Microwire-compatible 3-wire interface (CS/CLK/DI/DO), and industrial temperature range (–40°C to +85°C). It features self-timed erase/write cycles, automatic ERAL before WRAL, power-on/off data protection, and 1,000,000 endurance cycles - used in embedded system configuration storage, sensor calibration data retention, and firmware parameter backup.
For engineers reviewing the 93LC66AX-I/SN datasheet, 93LC66AX-I/SN pinout, 93LC66AX-I/SN application, or 93LC66AX-I/SN equivalent, key selection considerations include VCC range (2.5–5.5 V), absence of ORG pin (fixed x8 mode), SOIC-8 package compatibility, Ready/Busy status via DO pin, and Microwire protocol timing compliance at up to 3 MHz.
Technical Context
This device implements a synchronous serial Microwire interface with start-bit detection, opcode-driven command set (READ, WRITE, ERASE, ERAL, WRAL, EWEN/EWDS), and internal auto-erase-before-write logic. All programming operations are self-timed with no external delay required.
It uses CMOS EEPROM cell technology with on-chip voltage pump for write/erase, power-on reset circuitry to inhibit writes during brown-out, and high-impedance DO output except during read or status polling. The absence of ORG pin confirms fixed 8-bit word organization per the 'A' suffix.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Memory size | 4 Kbit (512 × 8-bit), sufficient for storing boot configuration, calibration coefficients, or small firmware patches |
| VCC range | 2.5 V to 5.5 V - supports direct interface with 3.3 V and 5 V microcontrollers without level shifting |
| Clock frequency | Up to 3 MHz at VCC ≥ 4.5 V - enables fast parameter updates in real-time control loops |
| Write cycle time | 6 ms typical - defines minimum interval between successive WRITE commands |
| Endurance | 1,000,000 erase/write cycles - ensures >10 years of daily reconfiguration in industrial logging systems |
| Data retention | >200 years at 25°C - guarantees nonvolatile storage integrity across product lifecycle |
| Temperature range | –40°C to +85°C (Industrial grade) - qualified for use in automotive body control modules and industrial PLC I/O cards |
Pinout & Package
8-pin SOIC package (SN suffix), 3.9 mm × 4.9 mm body, 1.27 mm pitch. Pin 1 marked by bevelled corner or laser dot; pin 1 ID confirmed per Microchip DS21795E-page 18.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 CS | Chip Select | Active-high enable; must be held low ≥250 ns between instructions to reset internal state |
| 2 CLK | Serial Clock | Rising-edge synchronized I/O; clock can be paused mid-transfer without corruption |
| 3 DI | Data Input | Accepts start bit, opcodes, addresses, and write data; tolerant of bus conflicts when shared with DO |
| 4 DO | Data Output / Status | Outputs read data or Ready/Busy (low = busy); enters High-Z when CS low or after status read |
| 5 VSS | Ground | Reference for all digital and analog circuitry; requires low-impedance connection to minimize noise coupling |
| 6 NC | No Connection | Internally unconnected; must be left floating or tied to VSS per layout best practice |
| 7 NC | No Connection | Internally unconnected; same handling as Pin 6 |
| 8 VCC | Power Supply | Supplies core logic and charge pump; requires local 0.1 µF ceramic decoupling adjacent to pin |
Key Features
| Feature | Design Value |
|---|---|
| Self-timed erase/write | Eliminates need for external timing control or software delays - simplifies driver implementation |
| Automatic ERAL before WRAL | Guarantees full-array readiness before bulk write, preventing partial-program corruption |
| Power-on/off data protection | Hardware lockout below 2.5 V threshold prevents accidental writes during power ramp-up/down |
| Ready/Busy status on DO | Enables efficient polling without dedicated status lines - reduces MCU GPIO count |
| Sequential read mode | Allows continuous address increment with single CS assertion - speeds up block reads |
Applications
| Motor Control Configuration | Smart Sensor Calibration |
|---|---|
Use Scenario: Storing motor phase alignment offsets, PID tuning parameters, and fault history in BLDC drive firmware. IC Role / Device Role / Timing Role: Nonvolatile configuration register accessed at startup and during field calibration. Use Value: Enables plug-and-play motor replacement without manual re-tuning; retains settings across 10+ year service life. | Use Scenario: Holding factory-calibrated gain/offset coefficients and temperature compensation tables for MEMS pressure sensors. IC Role / Device Role / Timing Role: Microwire-configurable memory mapped into sensor node's I/O space for runtime coefficient lookup. Use Value: Eliminates need for external calibration hardware; supports field recalibration with traceable NIST-referenced values. |
| Industrial HMI Settings | Medical Device User Profiles |
Use Scenario: Persisting display brightness, language selection, alarm thresholds, and user access levels in panel-mounted HMIs. IC Role / Device Role / Timing Role: Low-power serial EEPROM interfaced directly to ARM Cortex-M0+ host via GPIO bit-banged Microwire. Use Value: Survives 50,000+ power cycles; withstands ESD events per IEC 61000-4-2 Level 4 due to integrated protection. | Use Scenario: Securing patient-specific therapy parameters (e.g., infusion rate limits, drug concentration maps) in portable infusion pumps. IC Role / Device Role / Timing Role: Tamper-resistant configuration store with write-disable logic (EWDS) enforced after each save. Use Value: Meets IEC 62304 Class B software safety requirements for data integrity; supports audit trail via timestamped write cycles. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar serial EEPROM applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| 93LC66BT-I/SN | 16-bit organization (256 × 16), same VCC range and package; no ORG pin - fixed x16 mode | Requires 16-bit MCU data path or byte-swapped software handling; higher density per address but fewer total addresses | Select when system architecture uses 16-bit data transfers and memory map efficiency outweighs added software complexity |
| AT25040B-MAU-1.8 | SPI interface (4-wire), 4 Kbit (512 × 8), 1.8–5.5 V operation, 20 MHz max clock, same endurance and retention | Requires separate SPI peripheral or bit-banged 4-wire protocol; incompatible opcode set and timing model | Choose for designs already using SPI peripherals or requiring faster random access than Microwire allows |
Compared with 93LC66BT-I/SN, the 93LC66AX-I/SN provides simpler 8-bit-aligned addressing and avoids byte-order ambiguity; versus AT25040B-MAU-1.8, it saves one GPIO pin and maintains deterministic 3-wire timing but trades off peak throughput.
Availability
93LC66AX-I/SN is available at Aetrix Electronics and suitable for industrial control panels, medical diagnostics equipment, and automotive body electronics requiring stable component supply, long-term obsolescence management, and RoHS-compliant sourcing.
Supply support for 93LC66AX-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, mixed-signal, analog, and Flash-IP solutions, headquartered in Chandler, Arizona.
The 93LC66AX-I/SN belongs to Microchip's legacy 93XX series of Microwire-compatible EEPROMs, designed specifically for cost-sensitive, low-pin-count embedded systems needing reliable nonvolatile storage with minimal MCU resource usage.
FAQ
What is the function of the NC pins on the 93LC66AX-I/SN?
The 93LC66AX-I/SN has two No-Connection (NC) pins: Pin 6 and Pin 7. These terminals are not bonded internally and serve only mechanical or thermal roles in the SOIC-8 package. They must be left floating or connected to ground per PCB layout guidelines - neither pin may be used as a signal or power path. This design reflects the 'A' variant's fixed 8-bit organization, eliminating the ORG pin found on 'C' variants.
Does the 93LC66AX-I/SN require an external pull-up resistor on the DO pin?
No, the 93LC66AX-I/SN does not require an external pull-up on the DO pin. Its output buffer actively drives high or low during read or status polling, and enters true High-Z (not weak pull-up) when inactive. However, if DI and DO are wire-OR'd on a shared bus, a current-limiting resistor (typically 1–10 kΩ) is recommended between them to prevent bus conflict during the dummy-zero phase of READ commands.
How is write protection implemented on the 93LC66AX-I/SN?
Write protection on the 93LC66AX-I/SN is implemented via hardware and command-level controls: (1) Power-on default is Erase/Write Disable (EWDS) mode, blocking all programming until EWEN is issued; (2) VCC lockout disables writes below 2.5 V; (3) EWDS must be executed after every successful WRITE/ERAL/WRAL to re-enable protection. This three-tier scheme prevents accidental overwrites during power transients or software glitches.
Can the 93LC66AX-I/SN operate at 1.8 V?
No, the 93LC66AX-I/SN cannot operate at 1.8 V. Its specified VCC range is 2.5 V to 5.5 V, as confirmed in the Device Selection Table (DS21795E-page 1). Devices marked '93AA66A' support 1.8 V, but the 'LC' prefix denotes the 2.5 V minimum variant. Attempting operation below 2.5 V will result in undefined behavior, failed writes, or data corruption due to insufficient charge-pump voltage.
What is the maximum clock frequency supported by the 93LC66AX-I/SN at 3.3 V VCC?
At VCC = 3.3 V, the 93LC66AX-I/SN supports a maximum clock frequency of 2 MHz, as specified in Table 1-2 (A1, FCLK row) of DS21795E. This limit applies across the full industrial temperature range (–40°C to +85°C). Exceeding 2 MHz may cause setup/hold violations on DI or incorrect opcode recognition, especially near temperature extremes.
93LC66AX-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:
- 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:
- -40°C ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 8-SOIC
93LC66AX-I/SN FAQ
1.How can I place an order for 93LC66AX-I/SN through Aetrix?
Please submit a Request for Quotation (RFQ) for 93LC66AX-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 93LC66AX-I/SN reliable?
The price and inventory of 93LC66AX-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 93LC66AX-I/SN is usually 5 days.
3.What payment methods are accepted for 93LC66AX-I/SN?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for 93LC66AX-I/SN transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for 93LC66AX-I/SN?
93LC66AX-I/SN orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your 93LC66AX-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 93LC66AX-I/SN?
For technical support, including 93LC66AX-I/SN datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your 93LC66AX-I/SN requirements.
6.How does Aetrix verify that 93LC66AX-I/SN is sourced from the original manufacturer or authorized distributors?
All 93LC66AX-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 93LC66AX-I/SN meets industry standards.
7.What is the process for return or replacement of 93LC66AX-I/SN?
All 93LC66AX-I/SN units undergo pre-shipment inspection (PSI). If there is an issue with 93LC66AX-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 93LC66AX-I/SN part is unused and in its original packaging.
Return procedure for 93LC66AX-I/SN:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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