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Microchip Technology 93C66CT-E/ST
- Part No.:
- 93C66CT-E/ST
- Manufacturer:
- Microchip Technology
- Category:
- Memory
- Package:
- 8-TSSOP (0.173", 4.40mm Width)
- Datasheet:
-
93C66CT-E/ST.pdf
- Description:
- IC EEPROM 4KBIT MICROWIRE 8TSSOP
- Quantity:
- Payment:
- Shipping:
Inventory:3,997
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Product details
Overview
93C66CT-E/ST from Microchip Technology Inc. is a 4 Kbit serial EEPROM with Microwire-compatible 3-wire interface, fixed 8-bit organization (no ORG pin), 4.5–5.5 V supply range, and automotive-grade temperature operation (–40°C to +125°C). It delivers 1 million erase/write cycles, >200-year data retention, and integrated power-on/off data protection - used in engine control units, airbag modules, and automotive sensor calibration storage.
For engineers reviewing the 93C66CT-E/ST datasheet, 93C66CT-E/ST pinout, 93C66CT-E/ST application, or 93C66CT-E/ST equivalent, key selection criteria include its automotive temperature rating, dedicated 8-bit x512 organization, TSSOP-8 package, Microwire protocol compliance, and ERAL/WRAL bulk operations requiring ≥4.5 V VCC.
Technical Context
This device implements a synchronous serial interface using CS, CLK, and DI/DO lines with start-bit detection and opcode-driven command execution. It supports READ, WRITE, ERASE, ERAL, WRAL, EWEN, and EWDS instructions with distinct timing for 93C-series devices - notably initiating write cycles on the rising edge of CLK (not CS fall), and requiring VCC ≥4.5 V for ERAL/WRAL.
Internal logic includes an address decoder, mode decode logic, and output buffer with Ready/Busy status signaled via DO pin during programming. Power-on reset circuitry inhibits all operations below 3.8 V, and the device powers up in EWDS (Erase/Write Disable) state for data integrity.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Memory Size | 4 Kbit (512 × 8-bit organization) |
| VCC Range | 4.5 V to 5.5 V - mandates stable high-voltage rail; incompatible with 3.3 V systems |
| Temperature Range | –40°C to +125°C (Automotive E-grade) - qualified for under-hood and safety-critical ECUs |
| Endurance | 1,000,000 erase/write cycles - supports frequent calibration updates in vehicle lifetime |
| Data Retention | >200 years at +125°C - ensures firmware/config persistence over full automotive service life |
| Interface Protocol | Microwire-compatible 3-wire serial (CS/CLK/DI/DO) - requires no I²C pull-ups or SPI SS management |
| Write Cycle Time | 2 ms typical (TWC) - enables fast field updates without blocking host MCU |
Pinout & Package
93C66CT-E/ST is housed in an 8-lead TSSOP (Thin Shrink Small Outline Package) with 0.65 mm lead pitch, JEDEC MO-153 compliant, Pb-free Matte Tin finish, and exposed pad option (not connected per datasheet).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| CS | Chip Select | Active-high enable; must be held low ≥250 ns between instructions; deselects device into standby but completes ongoing writes |
| CLK | Serial Clock | Positive-edge synchronized; controls timing of opcode/address/data; rising edge initiates 93C-series write cycles |
| DI | Data Input | Receives start bit, opcodes, addresses, and write data; shares bus with DO only with external current-limiting resistor |
| DO | Data Output / Status | Outputs read data or Ready/Busy (low = busy); enters High-Z when CS low or after status polling |
| VSS | Ground | Reference for all I/O and internal logic; must be low-impedance connection for noise immunity |
| NC | No Internal Connection | Pin 7 is unconnected - must be left floating or tied to VSS per layout best practice |
| VCC | Power Supply | 4.5–5.5 V only; voltage detect threshold at 3.8 V prevents operation during brown-out |
| ORG | Organization Select | Not present on 93C66A/B variants - pin 6 is NC; fixed 8-bit mode eliminates configuration risk |
Key Features
| Feature | Design Value |
|---|---|
| Self-timed Erase/Write with Auto-Erase | Eliminates external timing control - host only monitors DO for Ready/Busy; reduces firmware overhead |
| Automatic ERAL before WRAL | Ensures clean memory before bulk write - no separate erase command needed, preventing partial-write corruption |
| Power-On/Off Data Protection | Hardware lockout below 3.8 V VCC - prevents inadvertent writes during power ramp-up/down in automotive transients |
| Device Status Signal (Ready/Busy) | Real-time DO pin feedback - enables non-blocking polling instead of fixed delays, improving system responsiveness |
| Sequential Read Function | Continuous data stream across addresses with single CS assertion - accelerates firmware dump or table reads |
Applications
| Engine Control Unit (ECU) Calibration Storage | Advanced Driver Assistance Systems (ADAS) Sensor Configuration |
|---|---|
Use Scenario: Storing fuel map coefficients, ignition timing tables, and OBD-II fault codes that require field updates via diagnostic port. IC Role / Device Role / Timing Role: Nonvolatile parameter storage with guaranteed write integrity during vehicle cranking (VCC dip) and thermal cycling. Use Value: 1M endurance and >200-year retention ensure calibration data survives 15+ year vehicle lifespan without degradation. | Use Scenario: Holding camera lens distortion profiles, radar beamforming parameters, and fusion algorithm weights updated during OTA software upgrades. IC Role / Device Role / Timing Role: Microwire-configurable EEPROM interfaced to ADAS SoC for secure, low-pin-count configuration storage. Use Value: TSSOP-8 footprint and automotive temp grade allow direct placement near vision/radar processors without derating. |
| Airbag Control Module Crash Data Logging | Electric Power Steering (EPS) Motor Position Offset Storage |
Use Scenario: Recording pre-crash vehicle speed, brake status, and seatbelt tension immediately before deployment for forensic analysis. IC Role / Device Role / Timing Role: Fail-safe event logger triggered by crash sensors; must retain data even after main power loss. Use Value: Power-on/off protection and 4.5–5.5 V operation ensure reliable write completion during battery disconnect events. | Use Scenario: Saving learned motor position offsets after each ignition cycle to maintain steering assist accuracy across battery replacements. IC Role / Device Role / Timing Role: Persistent offset register accessed at startup; requires deterministic 2 ms write time for fast boot sequence. Use Value: Fixed 8-bit organization simplifies MCU driver development versus variable-width alternatives. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar serial EEPROM applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| 93C66B-E/ST | 16-bit organization (256 × 16), same VCC/temp/package - requires ORG pin tied low or removed from design | Used where wider data path reduces instruction count for bulk transfers; not drop-in compatible due to address/data width mismatch | Select only if system firmware supports 16-bit addressing and data framing; verify clock timing margins at 2 MHz max for 2.5–4.5 V range |
| AT25DF041A-SH-B | SPI interface (4-wire), 4 Mbit density, 2.7–3.6 V operation, sector erase - no Microwire compatibility or ERAL/WRAL commands | Targets higher-density, lower-voltage embedded systems with SPI master; lacks automotive temp grade and automatic bulk erase | Choose for cost-sensitive consumer applications needing larger capacity; avoid in automotive due to missing AEC-Q100 qualification and 125°C operation |
Compared with 93C66B-E/ST, the 93C66CT-E/ST offers simpler 8-bit interface and guaranteed compatibility with legacy Microwire firmware; versus AT25DF041A-SH-B, it provides automotive qualification, deterministic 2 ms writes, and hardware-enabled bulk operations - critical for safety-critical reprogramming.
Availability
93C66CT-E/ST is available at Aetrix Electronics and suitable for engine control units, airbag modules, and ADAS sensor calibration requiring stable component supply across extended automotive production lifecycles.
Supply support for 93C66CT-E/ST 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, with global manufacturing and support infrastructure.
The 93Cxx series is designed specifically for automotive and industrial serial EEPROM applications demanding high reliability, wide temperature operation, and Microwire protocol compatibility - emphasizing data integrity under electrical and thermal stress.
FAQ
What is the maximum clock frequency supported by the 93C66CT-E/ST?
The 93C66CT-E/ST supports up to 3 MHz clock frequency when VCC is 4.5–5.5 V. This is specified in Table 1-2 (Param. No. A1) of DS21795E. Operation above this frequency risks setup/hold violations and failed instruction execution. The device does not support higher speeds even with tighter timing margins - the 3 MHz limit is absolute for guaranteed functionality.
Does the 93C66CT-E/ST require an external pull-up resistor on the DO pin?
No, the 93C66CT-E/ST does not require an external pull-up on DO. Its output buffer actively drives high/low states during READ and Ready/Busy reporting, and enters High-Z when inactive. Pull-ups may cause contention during status polling or sequential reads. Per Section 2.2, if DI and DO are shorted, a current-limiting resistor (not pull-up) is required to prevent bus conflict.
Can the 93C66CT-E/ST be used in a 3.3 V system?
No, the 93C66CT-E/ST cannot be used in a 3.3 V system. Its VCC range is strictly 4.5–5.5 V (Table on DS21795E page 1), and its power-on reset threshold is 3.8 V. Operating below 4.5 V violates absolute maximum ratings and will result in undefined behavior, failed writes, or data corruption. For 3.3 V designs, consider 93LC66A/B/C or 93AA66A/B/C variants.
What happens if the ORG pin is left floating on the 93C66CT-E/ST?
The ORG pin is not present on the 93C66CT-E/ST - it is a 93C66A variant with fixed 8-bit organization, and Pin 6 is designated NC (No Connection) per Table 3-1 and Package Type diagrams. Leaving Pin 6 unconnected has no effect; it must not be driven or tied to any voltage, as it is internally unconnected per datasheet.
Is the 93C66CT-E/ST AEC-Q100 qualified?
Yes, the 93C66CT-E/ST is AEC-Q100 qualified. The "E" suffix denotes Automotive Grade (–40°C to +125°C), and Microchip's official documentation confirms AEC-Q100 qualification for the 93Cxx-E series. This includes stress testing for temperature cycling, HTOL, ESD, and other automotive reliability requirements - essential for use in safety-critical vehicle subsystems.
93C66CT-E/ST Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Microchip Technology
- Series:
- -
- Package/Case:
- 8-TSSOP (0.173", 4.40mm Width)
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- 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:
- 3 MHz
- Write Cycle Time - Word, Page:
- 2ms
- Access Time:
- -
- Voltage - Supply:
- 4.5V ~ 5.5V
- Operating Temperature:
- -40°C ~ 125°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 8-TSSOP
93C66CT-E/ST FAQ
1.How can I place an order for 93C66CT-E/ST through Aetrix?
Please submit a Request for Quotation (RFQ) for 93C66CT-E/ST 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 93C66CT-E/ST reliable?
The price and inventory of 93C66CT-E/ST are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for 93C66CT-E/ST is usually 5 days.
3.What payment methods are accepted for 93C66CT-E/ST?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for 93C66CT-E/ST transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for 93C66CT-E/ST?
93C66CT-E/ST orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your 93C66CT-E/ST 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 93C66CT-E/ST?
For technical support, including 93C66CT-E/ST datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your 93C66CT-E/ST requirements.
6.How does Aetrix verify that 93C66CT-E/ST is sourced from the original manufacturer or authorized distributors?
All 93C66CT-E/ST 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 93C66CT-E/ST meets industry standards.
7.What is the process for return or replacement of 93C66CT-E/ST?
All 93C66CT-E/ST units undergo pre-shipment inspection (PSI). If there is an issue with 93C66CT-E/ST, 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 93C66CT-E/ST part is unused and in its original packaging.
Return procedure for 93C66CT-E/ST:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
93C66CT-E/ST Tags
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