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Microchip Technology 93LC66AT-I/SN
- Part No.:
- 93LC66AT-I/SN
- Manufacturer:
- Microchip Technology
- Category:
- Memory
- Package:
- 8-SOIC (0.154", 3.90mm Width)
- Datasheet:
-
93LC66AT-I/SN.pdf
- Description:
- IC EEPROM 4KBIT MICROWIRE 8SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:14,014
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Product details
Overview
93LC66AT-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 retention, and firmware parameter backup.
For engineers reviewing the 93LC66AT-I/SN datasheet, 93LC66AT-I/SN pinout, 93LC66AT-I/SN application, or 93LC66AT-I/SN equivalent, key selection criteria 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 support for sequential read and WRAL/ERAL commands.
Technical Context
The 93LC66AT-I/SN 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. Its memory array is organized as 512 words × 8 bits, with no ORG pin - eliminating external configuration logic required by 'C' variants.
It uses CMOS technology with on-chip voltage detection (VPOR = 1.5 V) for power-on data protection, supports clock frequencies up to 3 MHz at VCC ≥ 4.5 V, and provides high-impedance DO output during standby and non-read operations - enabling shared bus operation with pull-up resistors.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Memory size | 4 Kbit (512 × 8-bit), fixed x8 organization - no ORG pin required; simplifies PCB layout vs. configurable variants. |
| VCC range | 2.5 V to 5.5 V - compatible with 3.3 V and 5 V systems; enables direct interfacing with microcontrollers without level shifters. |
| Endurance | 1,000,000 erase/write cycles - supports frequent field updates in telemetry or calibration applications. |
| Data retention | >200 years at 25°C - ensures long-term reliability in unattended industrial equipment. |
| Write cycle time | 6 ms typical (TWC) - deterministic timing allows precise host software timeout handling. |
| Interface | 3-wire Microwire (CS/CLK/DI/DO) - minimal GPIO usage; supports daisy-chaining only via discrete CS lines. |
| Temp range | –40°C to +85°C (Industrial grade) - validated for use in factory automation and outdoor metering. |
Pinout & Package
8-pin 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 absent - confirms fixed 8-bit operation per device family specification.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| CS (Pin 1) | Chip Select | Active-high enable; must be held low ≥250 ns between instructions; initiates self-timed write on falling edge. |
| CLK (Pin 2) | Serial Clock | Synchronizes all data transfers; rising-edge sampling for DI/DO; stoppable mid-sequence for host flexibility. |
| DI (Pin 3) | Data Input | Receives start bit, opcodes, addresses, and write data; requires setup/hold timing relative to CLK. |
| DO (Pin 4) | Data Output / Status | Outputs read data or Ready/Busy (low = busy); enters High-Z when CS low or during non-read states. |
| VSS (Pin 5) | Ground | Reference for all I/O and internal circuitry; must be low-impedance connection to avoid noise-induced corruption. |
| NC (Pin 6, 7) | No Connection | Internally unconnected; may be left floating or tied to ground per board design rules - no functional impact. |
| VCC (Pin 8) | Power Supply | Supplies core logic and memory array; includes internal POR circuit triggering at 1.5 V for data integrity. |
Key Features
| Feature | Design Value |
|---|---|
| Self-timed erase/write | Eliminates need for external timing control or polling delays beyond TWC = 6 ms - reduces firmware complexity. |
| Automatic ERAL before WRAL | Guarantees full-array erase prior to bulk write - prevents partial-data corruption during firmware update sequences. |
| Power-on/off data protection | Hardware-level VPOR circuit blocks writes below 1.5 V - prevents inadvertent writes during brown-out or power ramp. |
| Ready/Busy status on DO | Enables efficient polling instead of fixed delays - improves system responsiveness during write-intensive operations. |
| Sequential read mode | Allows continuous address increment with single CS assertion - reduces transaction overhead for block reads. |
Applications
| Industrial Sensor Calibration Storage | Embedded System Configuration Memory |
|---|---|
Use Scenario: Storing factory-trimmed offset/gain coefficients for analog sensor front-ends in programmable logic controllers. IC Role / Device Role / Timing Role: Nonvolatile parameter register accessed at power-up and during field recalibration routines. Use Value: 200-year data retention ensures calibration remains valid across product lifetime without battery backup. | Use Scenario: Holding user-configurable settings (baud rate, network ID, alarm thresholds) in HVAC controllers. IC Role / Device Role / Timing Role: Serial configuration store interfaced directly to MCU GPIOs using Microwire protocol. Use Value: 1M endurance supports daily configuration changes over 27 years - exceeds typical field service intervals. |
| Firmware Parameter Backup | Smart Meter Tamper-Resistant Log |
Use Scenario: Saving runtime-calculated compensation values (e.g., battery aging models) in portable medical devices. IC Role / Device Role / Timing Role: Low-power backup memory updated only on significant state changes. Use Value: 2.5 V minimum VCC enables operation during brown-out conditions where main supply dips to 2.7 V. | Use Scenario: Recording tamper events (cover removal, magnetic field detection) with timestamp and counter in utility meters. IC Role / Device Role / Timing Role: Secure event log with hardware write-protection (EWDS/EWEN) preventing unauthorized overwrite. Use Value: Power-on data protection ensures logs survive sudden power loss during critical event capture. |
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 range and package - requires ORG pin tied to VSS for x8 emulation, but not present on 'A'/'B' variants. | Not pin-compatible: lacks ORG pin; incompatible instruction timing for x16 addressing - cannot substitute without firmware rework. | Select only if migrating to 16-bit data path; requires full interface redesign and validation. |
| AT25040B-MAHL-T | SPI interface (4-wire), 4 Kbit (512 × 8), 1.8–5.5 V, SOIC-8 - different protocol, no Ready/Busy pin, uses Write Enable latch instead of EWEN/EWDS. | Requires SPI-capable MCU peripheral; no hardware status polling - increases software overhead for write completion checks. | Choose when SPI is already used elsewhere in design; avoid if Microwire legacy compatibility or DO-based polling is required. |
Compared with 93LC66B-I/SN and AT25040B-MAHL-T, the 93LC66AT-I/SN offers native x8 Microwire compatibility with integrated Ready/Busy signaling and proven industrial-grade reliability - making it optimal for cost-sensitive, firmware-light embedded systems requiring deterministic timing and minimal GPIO usage.
Availability
93LC66AT-I/SN is available at Aetrix Electronics and suitable for industrial sensor calibration storage, embedded system configuration memory, and firmware parameter backup requiring stable component supply and long-term obsolescence management.
Supply support for 93LC66AT-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 93LC66AT-I/SN belongs to Microchip's legacy 93XX serial EEPROM product line, designed specifically for low-power, nonvolatile memory applications in space-constrained industrial and automotive systems where Microwire interface simplicity and data integrity are critical.
FAQ
What is the memory organization of the 93LC66AT-I/SN?
The 93LC66AT-I/SN has a fixed 512 × 8-bit (4 Kbit) organization with no ORG pin - confirming it is an 'A' variant per Microchip's device selection table. This eliminates external configuration logic and guarantees x8 data width compatibility with 8-bit microcontroller peripherals.
Does the 93LC66AT-I/SN support sequential read operation?
Yes, the 93LC66AT-I/SN supports sequential read: when CS remains high after a READ instruction, the internal address counter automatically increments, allowing continuous output of consecutive memory locations on the DO pin - reducing transaction overhead for block data retrieval.
What is the purpose of the NC pins on the 93LC66AT-I/SN SOIC-8 package?
Pins 6 and 7 on the 93LC66AT-I/SN are marked NC (No Connection) - internally unconnected and functionally inert. They may be left floating or tied to ground per PCB design rules, with no impact on device operation or timing behavior.
How does the 93LC66AT-I/SN handle power-loss during write operations?
The 93LC66AT-I/SN incorporates hardware power-on/off data protection: its internal voltage detector (VPOR = 1.5 V) disables all write functions when VCC drops below threshold - preventing partial writes and ensuring data integrity even during abrupt power failure.
Can the 93LC66AT-I/SN be used in automotive applications?
No - the 93LC66AT-I/SN is rated for Industrial temperature range (–40°C to +85°C), not Automotive (–40°C to +125°C). For automotive use, Microchip specifies the 93LC66A-E/SN variant, which undergoes extended qualification testing and carries the 'E' suffix in its part number.
93LC66AT-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:
- 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
93LC66AT-I/SN FAQ
1.How can I place an order for 93LC66AT-I/SN through Aetrix?
Please submit a Request for Quotation (RFQ) for 93LC66AT-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 93LC66AT-I/SN reliable?
The price and inventory of 93LC66AT-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 93LC66AT-I/SN is usually 5 days.
3.What payment methods are accepted for 93LC66AT-I/SN?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for 93LC66AT-I/SN transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for 93LC66AT-I/SN?
93LC66AT-I/SN orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your 93LC66AT-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 93LC66AT-I/SN?
For technical support, including 93LC66AT-I/SN datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your 93LC66AT-I/SN requirements.
6.How does Aetrix verify that 93LC66AT-I/SN is sourced from the original manufacturer or authorized distributors?
All 93LC66AT-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 93LC66AT-I/SN meets industry standards.
7.What is the process for return or replacement of 93LC66AT-I/SN?
All 93LC66AT-I/SN units undergo pre-shipment inspection (PSI). If there is an issue with 93LC66AT-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 93LC66AT-I/SN part is unused and in its original packaging.
Return procedure for 93LC66AT-I/SN:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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