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Microchip Technology 93LC66A-I/SN
- Part No.:
- 93LC66A-I/SN
- Manufacturer:
- Microchip Technology
- Category:
- Memory
- Package:
- 8-SOIC (0.154", 3.90mm Width)
- Datasheet:
-
93LC66A-I/SN.pdf
- Description:
- IC EEPROM 4KBIT MICROWIRE 8SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:1,432
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Product details
Overview
93LC66A-I/SN from Microchip Technology Inc. is a 4 Kbit (512 × 8-bit) low-voltage serial EEPROM with Microwire-compatible 3-wire interface, operating from 2.5 V to 5.5 V, rated for Industrial temperature range (–40°C to +85°C), and housed in an 8-lead SOIC package (SN). It delivers 1 million erase/write cycles, >200 years data retention, and integrated power-on/off data protection - used for configuration storage in embedded controllers and sensor calibration registers.
For engineers reviewing the 93LC66A-I/SN datasheet, 93LC66A-I/SN pinout, 93LC66A-I/SN application, or 93LC66A-I/SN equivalent, key selection criteria include its fixed 8-bit organization (no ORG pin), self-timed erase/write (6 ms typical), Ready/Busy status via DO pin, and compatibility with legacy Microwire host controllers requiring minimal GPIO overhead.
Technical Context
The 93LC66A-I/SN implements a synchronous serial interface using CS, CLK, and DI/DO signals with start-bit detection and opcode-based command decoding. Its internal architecture includes an address counter, mode decode logic, and output buffer enabling sequential read without reissuing addresses.
It supports full memory operations - READ (20 clock cycles), WRITE (20 clocks + 6 ms auto-erase/write), ERASE (12 clocks + 6 ms), ERAL (12 clocks + 6 ms), and WRAL (20 clocks + 15 ms) - all initiated by CS falling edge (for AA/LC variants), with DO pin providing real-time Ready/Busy status during active programming.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Memory Size | 4 Kbit (512 × 8-bit) - fixed x8 organization; no ORG pin required or functional. |
| VCC Range | 2.5 V to 5.5 V - supports wide supply margin in battery-backed or mixed-voltage systems. |
| Endurance | 1,000,000 erase/write cycles - enables frequent field updates in calibration or logging applications. |
| Data Retention | >200 years at +25°C - ensures long-term reliability in unattended industrial deployments. |
| Write Cycle Time | 6 ms typical - self-timed; eliminates need for external timing control or polling delay estimation. |
| Interface | Microwire-compatible 3-wire serial (CS/CLK/DI/DO) - requires only 4 GPIOs; no SPI mode bits or frame sync needed. |
| Temp Range | –40°C to +85°C (Industrial grade) - validated across full range for stable timing and leakage performance. |
| Package | 8-lead SOIC (SN) - industry-standard footprint compatible with automated assembly and legacy PCB layouts. |
Pinout & Package
8-lead SOIC (SN) package with standard pinout: Pin 1 = CS, Pin 2 = CLK, Pin 3 = DI, Pin 4 = DO, Pin 5 = VSS, Pin 6 = NC (no internal connection), Pin 7 = NC, Pin 8 = VCC. ORG pin is not present on 'A' devices; Pins 6 and 7 are unconnected and must be left floating or tied to ground per layout best practice.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 - CS | Chip Select | Active-high enable; device enters standby when low; minimum 250 ns low time required between commands. |
| 2 - CLK | Serial Clock | Rising-edge synchronized I/O; clock can be paused mid-transfer; TCKH/TCKL vary with VCC. |
| 3 - DI | Data Input | Accepts start bit, opcode, address, and data; high-impedance when not selected. |
| 4 - DO | Data Output / Status | Outputs read data or Ready/Busy (low = busy); high-Z when CS low or during non-read states. |
| 5 - VSS | Ground | Reference for all I/O and internal logic; must be low-impedance connection to minimize noise coupling. |
| 6 - NC | No Connection | Not bonded internally; leave unconnected or tie to VSS for mechanical stability (not electrically required). |
| 7 - NC | No Connection | Identical to Pin 6; unused in 93LC66A-I/SN; no routing or termination needed. |
| 8 - VCC | Power Supply | 2.5–5.5 V operation; internal POR triggers at ~1.5 V; decoupling capacitor (0.1 µF) required near pin. |
Key Features
| Feature | Design Value |
|---|---|
| Self-timed Erase/Write | Eliminates external timing circuitry; 6 ms typical cycle completes autonomously after CS fall. |
| Ready/Busy Status on DO | Enables efficient polling without dedicated status lines; avoids blocking delays in interrupt-driven firmware. |
| Power-On/Off Data Protection | Hardware lockout below ~1.5 V VCC; prevents corruption during brown-out or hot-swap events. |
| Sequential Read Mode | Automatically increments address on successive reads while CS remains high - reduces host CPU overhead. |
| Erase All (ERAL) & Write All (WRAL) | Atomic bulk operations: ERAL clears entire array; WRAL writes full memory with embedded ERAL - both require VCC ≥4.5 V. |
| EWEN/EWDS Security Commands | Prevents accidental writes: device powers up in EWDS (write-disabled); EWEN must precede any program command. |
Applications
| Industrial Sensor Calibration | Embedded Controller Configuration |
|---|---|
Use Scenario: Storing factory-trimmed offset/gain coefficients for analog sensor front-ends in programmable logic controllers. IC Role / Device Role / Timing Role: Nonvolatile configuration register accessed at boot and during field recalibration; operates at 1 MHz clock under 3.3 V. Use Value: Enables single-device calibration storage with guaranteed 200-year retention and 1M-cycle endurance for periodic field updates. | Use Scenario: Holding user-defined I/O mapping, communication protocol settings, and watchdog timeout values in HVAC controller mainboards. IC Role / Device Role / Timing Role: System parameter store accessed via Microwire-compatible GPIO bit-banging; supports sequential read of 16-byte config block. Use Value: Reduces BOM count by replacing discrete NVSRAM; eliminates battery backup while maintaining data integrity across power cycles. |
| Medical Device Settings Storage | Automotive Body Control Module (BCM) Trim Data |
Use Scenario: Saving patient-specific therapy parameters and usage logs in portable infusion pumps compliant with IEC 62304. IC Role / Device Role / Timing Role: Safety-critical data archive with hardware write-protection (EWDS default); accessed only during maintenance mode. Use Value: Meets Class C software requirements via deterministic 6 ms write latency and built-in POR lockout below 1.5 V. | Use Scenario: Storing door lock actuator calibration offsets and mirror position presets in automotive BCMs operating across –40°C to +85°C. IC Role / Device Role / Timing Role: Temperature-stable NV memory interfaced to 8-bit MCU with limited SPI peripherals; uses 3-wire Microwire for pin-constrained design. Use Value: Qualified for Industrial temp range with verified AC timing down to 2.5 V - ensures reliable operation during cold cranking (battery dip to 6 V). |
Equivalent & Alternatives
The following parts are listed as comparable options for similar serial EEPROM applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| 93LC66B-I/SN | 16-bit organization (256 × 16); same VCC, timing, and package - but incompatible data width and instruction set. | Requires host firmware rewrite for 16-bit addressing and dual-byte data transfers; unsuitable for existing 8-bit protocols. | Select only if system architecture mandates 16-bit word access and host controller supports extended opcode handling. |
| AT25040B-MAHL-T | SPI interface (4-wire), 4 Kbit (512 × 8), 1.8–5.5 V, 20 MHz max clock; no Ready/Busy pin - relies on WIP flag polling. | Needs SPI peripheral instead of GPIO bit-banged Microwire; lacks hardware status signal - increases firmware complexity for write synchronization. | Choose when higher throughput (20 MHz vs. 3 MHz) or SPI-native host is available; avoid if Microwire legacy support or DO status polling is required. |
Compared with 93LC66B-I/SN, the 93LC66A-I/SN provides native 8-bit compatibility and simpler firmware integration; versus AT25040B-MAHL-T, it offers deterministic timing and hardware-ready signaling at lower clock speeds - critical for resource-constrained microcontrollers.
Availability
93LC66A-I/SN is available at Aetrix Electronics and suitable for industrial sensor calibration, embedded controller configuration, and medical device settings storage requiring stable component supply across extended product lifecycles.
Supply support for 93LC66A-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 93LC66A-I/SN belongs to Microchip's legacy 93XX serial EEPROM family, designed specifically for cost-sensitive, low-pin-count embedded systems needing robust nonvolatile storage without complex interface logic or external timing components.
FAQ
What is the memory organization of the 93LC66A-I/SN?
The 93LC66A-I/SN has a fixed 512 × 8-bit (4 Kbit) organization with no ORG pin. Unlike 'C' variants, it does not support configurable word size - all instructions and data transfers operate strictly in 8-bit mode. This simplifies host driver development and eliminates external logic for memory width selection.
Does the 93LC66A-I/SN support hardware write protection?
Yes, the 93LC66A-I/SN implements hardware write protection via EWEN/EWDS commands. It powers up in EWDS (Erase/Write Disable) state, blocking all programming until an explicit EWEN instruction is issued. This prevents accidental overwrites during power-up transients or firmware glitches - a critical feature for safety-critical storage.
What is the maximum clock frequency supported by the 93LC66A-I/SN?
The 93LC66A-I/SN supports up to 3 MHz clock frequency when VCC ≥4.5 V. At 2.5–4.5 V, the maximum is 2 MHz, and at 1.8–2.5 V (not applicable to this part), it would be 1 MHz. The 93LC66A-I/SN's specified VCC range (2.5–5.5 V) means its operational max is 2 MHz (2.5–4.5 V) or 3 MHz (4.5–5.5 V), per DS21795E Table 1-2.
How does the Ready/Busy status work on the 93LC66A-I/SN?
The DO pin of the 93LC66A-I/SN serves dual function: data output during READ and Ready/Busy indicator during programming. When CS is brought high after ≥250 ns low time post-command, DO goes low to indicate ongoing erase/write and high when complete. Issuing a Start bit then lowering CS clears the status - enabling precise firmware synchronization without fixed delays.
Is the 93LC66A-I/SN RoHS compliant and Pb-free?
Yes, the 93LC66A-I/SN is Pb-free and RoHS compliant, with Matte Tin (Sn) finish on all package leads. This is explicitly stated in the device features list (DS21795E-page 1) and confirmed in the Packaging Information section. The SN (SOIC) package meets JEDEC J-STD-020 moisture sensitivity level MSL-1.
93LC66A-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:
- 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
93LC66A-I/SN FAQ
1.How can I place an order for 93LC66A-I/SN through Aetrix?
Please submit a Request for Quotation (RFQ) for 93LC66A-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 93LC66A-I/SN reliable?
The price and inventory of 93LC66A-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 93LC66A-I/SN is usually 5 days.
3.What payment methods are accepted for 93LC66A-I/SN?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for 93LC66A-I/SN transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for 93LC66A-I/SN?
93LC66A-I/SN orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your 93LC66A-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 93LC66A-I/SN?
For technical support, including 93LC66A-I/SN datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your 93LC66A-I/SN requirements.
6.How does Aetrix verify that 93LC66A-I/SN is sourced from the original manufacturer or authorized distributors?
All 93LC66A-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 93LC66A-I/SN meets industry standards.
7.What is the process for return or replacement of 93LC66A-I/SN?
All 93LC66A-I/SN units undergo pre-shipment inspection (PSI). If there is an issue with 93LC66A-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 93LC66A-I/SN part is unused and in its original packaging.
Return procedure for 93LC66A-I/SN:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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