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Microchip Technology 93C66CT-I/ST
- Part No.:
- 93C66CT-I/ST
- Manufacturer:
- Microchip Technology
- Category:
- Memory
- Package:
- 8-TSSOP (0.173", 4.40mm Width)
- Datasheet:
-
93C66CT-I/ST.pdf
- Description:
- IC EEPROM 4KBIT MICROWIRE 8TSSOP
- Quantity:
- Payment:
- Shipping:
Inventory:4,698
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Product details
Overview
93C66CT-I/ST from Microchip Technology Inc. is a 4 Kbit low-voltage serial EEPROM with 512 × 8-bit organization, designed for nonvolatile data storage in microcontroller-based systems. It operates within 4.5–5.5 V supply range, supports Industrial temperature (−40°C to +85°C), and uses Microwire-compatible 3-wire serial interface (CS, CLK, DI, DO). Its self-timed erase/write cycles, automatic ERAL/WRAL, and power-on/off data protection make it suitable for configuration memory in industrial control modules.
For engineers reviewing the 93C66CT-I/ST datasheet, 93C66CT-I/ST pinout, 93C66CT-I/ST application, or 93C66CT-I/ST equivalent, key selection criteria include its fixed 8-bit word size (no ORG pin), TSSOP-8 package, 2 ms write cycle time, Ready/Busy status signaling via DO, and compatibility with legacy Microwire host controllers requiring minimal firmware changes.
Technical Context
The 93C66CT-I/ST 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. It requires no external timing components and completes all erase/write operations autonomously after CS falling edge (for 93C versions).
Its memory array is organized as 512 words × 8 bits, with dedicated 8-bit communication path and no ORG pin functionality-unlike 'C' variants. Device status is monitored via DO pin during programming, and data integrity is enforced by VCC voltage detect (3.8 V threshold) and power-on reset circuitry.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Memory Size | 4 Kbit (512 × 8-bit), providing compact nonvolatile storage for calibration data or device settings |
| VCC Range | 4.5–5.5 V - compatible with standard 5 V logic systems; disables operation below 3.8 V for data retention safety |
| Write Cycle Time | 2 ms - enables fast field updates without blocking host MCU for extended periods |
| Endurance | 1,000,000 erase/write cycles - supports long-term use in frequently reconfigured industrial nodes |
| Data Retention | 200 years - ensures configuration persistence across product lifecycle without refresh |
| Interface | Microwire-compatible 3-wire serial (CS, CLK, DI, DO) - minimal pin count, no SPI mode select needed |
| Temp Range | −40°C to +85°C (Industrial grade) - validated for operation in factory automation and motor drive environments |
Pinout & Package
93C66CT-I/ST is housed in an 8-lead TSSOP (Thin Shrink Small Outline Package) with 0.65 mm lead pitch, optimized for high-density PCB layouts and automated assembly. Pin 1 is marked by laser dot; package is Pb-free and RoHS compliant.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 (CS) | Chip Select | Active-high enable; must be held low ≥250 ns between commands; initiates self-timed write on falling edge |
| 2 (CLK) | Serial Clock | Synchronizes all data transfers; rising edge clocks in opcodes, addresses, and data; stoppable mid-sequence |
| 3 (DI) | Data Input | Receives start bit, instruction opcodes, address bits, and write data; shares no internal connection with DO |
| 4 (DO) | Data Output / Status | Outputs read data or Ready/Busy signal (low = busy); enters High-Z when CS low or during standby |
| 5 (VSS) | Ground | Reference return path for all signals; must be low-impedance to minimize noise coupling into serial interface |
| 6 (NC) | No Connect | Internally unconnected; must be left floating or tied to VSS per layout best practice - no functional role |
| 7 (ORG) | Organization Select | Not present on 93C66A/B devices - pin is NC; 93C66CT-I/ST is fixed 8-bit, no word-size configuration |
| 8 (VCC) | Power Supply | 4.5–5.5 V supply; includes on-chip voltage detector (trip at 3.8 V) to inhibit writes during brownout |
Key Features
| Feature | Design Value |
|---|---|
| Self-timed Erase/Write | Eliminates need for external timing control or polling delays beyond DO status check - reduces firmware overhead |
| Automatic ERAL before WRAL | Ensures full-array write reliability without separate erase command - simplifies configuration update sequences |
| Power-On/Off Data Protection | Hardware-enforced write inhibition below 3.8 V prevents corruption during power ramp-up/down transients |
| Ready/Busy Status on DO | Enables efficient polling instead of fixed delay waits - improves system responsiveness and determinism |
| Industry Standard 3-Wire Interface | Reduces MCU GPIO usage vs. parallel EEPROMs; avoids SPI mode conflicts and clock polarity setup complexity |
Applications
| Industrial Sensor Calibration | Motor Drive Configuration Storage |
|---|---|
Use Scenario: Storing factory-trimmed offset/gain coefficients and linearization tables for analog sensor front-ends in PLC I/O modules. IC Role / Device Role / Timing Role: Nonvolatile configuration memory accessed infrequently during commissioning or recalibration; supports sequential read for table fetch. Use Value: Maintains accuracy over 200 years without battery backup; 1M endurance allows field recalibration every 3 months for 27+ years. | Use Scenario: Holding motor-specific parameters (pole count, current limits, commutation angles) in embedded servo drives. IC Role / Device Role / Timing Role: Persistent parameter store updated only during firmware upgrade or commissioning; accessed at boot via Microwire interface. Use Value: 2 ms write time enables full parameter set update in <50 ms; 4.5–5.5 V range matches drive's 5 V auxiliary rail. |
| Medical Device Setup Profiles | Smart Energy Meter Tariff Tables |
Use Scenario: Saving user-defined therapy profiles (pressure ramps, duration, alarms) in portable respiratory equipment. IC Role / Device Role / Timing Role: Secure, low-power nonvolatile memory retaining settings across battery swaps and shutdowns. Use Value: −40°C to +85°C rating covers clinical and transport environments; RoHS/Pb-free compliance meets medical regulatory requirements. | Use Scenario: Storing time-of-use tariff schedules and billing history in DIN-rail mounted electricity meters. IC Role / Device Role / Timing Role: Tamper-resistant configuration memory updated quarterly via secure download; accessed during meter initialization. Use Value: Automatic ERAL/WRAL support simplifies full-table overwrite; VCC detect prevents corruption during grid voltage sags. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar serial EEPROM applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| 93LC66AT-I/ST | Wider VCC range (2.5–5.5 V); same 512×8 organization and TSSOP-8 package | Supports 3.3 V systems; lacks 93C66's higher VCC noise immunity and brownout threshold (1.5 V vs. 3.8 V) | Choose for mixed-voltage designs where 3.3 V operation is required; verify system noise margin at 2.5 V min. |
| AT25040B-SSHL-T | SPI interface (4-wire), 512×8 capacity, 1.8–5.5 V, SOIC-8 package | Requires SPI-capable MCU; no Ready/Busy pin - relies on fixed timing or WIP polling; different pinout | Prefer when migrating to SPI-based platforms or consolidating interface standards; redesign needed for pinout and protocol. |
Compared with 93LC66AT-I/ST, the 93C66CT-I/ST offers superior power-supply noise immunity and deterministic brownout protection but sacrifices 3.3 V compatibility. Against AT25040B-SSHL-T, it retains Microwire simplicity and DO-based status signaling but requires dedicated host logic for start-bit detection and opcode parsing.
Availability
93C66CT-I/ST is available at Aetrix Electronics and suitable for industrial control systems, motor drive commissioning tools, and medical device manufacturing requiring stable component supply with guaranteed long-term availability and traceable sourcing.
Supply support for 93C66CT-I/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, and Flash-IP solutions, headquartered in Chandler, Arizona, with global design and manufacturing operations.
The 93Cxx EEPROM family was engineered for cost-sensitive, low-pin-count embedded systems needing reliable, low-power nonvolatile storage - especially where Microwire interface compatibility and hardware write protection are critical.
FAQ
What is the function of the ORG pin on the 93C66CT-I/ST?
The ORG pin is not functional on the 93C66CT-I/ST. As a '66A' variant, this device has fixed 8-bit organization and no ORG pin implementation - Pin 7 is designated NC (No Connection) per the datasheet. Only 'C' variants (e.g., 93C66CT-I/ST-C) support ORG-driven word-size selection.
Does the 93C66CT-I/ST support SPI communication?
No, the 93C66CT-I/ST does not support SPI. It implements a Microwire-compatible 3-wire serial interface (CS, CLK, DI, DO) with start-bit detection and opcode-based command structure. SPI requires four wires (including MOSI/MISO separation) and mode-selectable clock polarity/phase - neither supported by the 93C66CT-I/ST.
What is the minimum VCC level that permits write operations on the 93C66CT-I/ST?
Write operations on the 93C66CT-I/ST are inhibited below 3.8 V, as defined by its internal VCC voltage detect circuit. The device remains in write-protection mode until VCC rises above this threshold, preventing data corruption during power-up or brownout conditions - a key reliability feature of the 93C66CT-I/ST.
How is Ready/Busy status monitored on the 93C66CT-I/ST?
Ready/Busy status is monitored on the DO pin of the 93C66CT-I/ST: DO outputs low during active erase/write cycles and goes high upon completion. To sample status, CS must be brought high for ≥250 ns after the command initiation; DO then reflects readiness. Issuing a new Start bit clears prior status - a behavior confirmed in the 93C66CT-I/ST functional description.
Is the 93C66CT-I/ST pin-compatible with other 93XX66 devices in TSSOP-8 package?
Yes, the 93C66CT-I/ST is pin-compatible with all 93XX66A/B/C variants in TSSOP-8 (ST) package - including 93AA66A, 93LC66B, and 93C66C - sharing identical pinout (CS, CLK, DI, DO, VSS, NC, ORG/NC, VCC). However, ORG functionality and VCC ranges differ across variants, so electrical and functional compatibility must be verified per application.
93C66CT-I/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 ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 8-TSSOP
93C66CT-I/ST FAQ
1.How can I place an order for 93C66CT-I/ST through Aetrix?
Please submit a Request for Quotation (RFQ) for 93C66CT-I/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-I/ST reliable?
The price and inventory of 93C66CT-I/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-I/ST is usually 5 days.
3.What payment methods are accepted for 93C66CT-I/ST?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for 93C66CT-I/ST transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for 93C66CT-I/ST?
93C66CT-I/ST orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your 93C66CT-I/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-I/ST?
For technical support, including 93C66CT-I/ST datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your 93C66CT-I/ST requirements.
6.How does Aetrix verify that 93C66CT-I/ST is sourced from the original manufacturer or authorized distributors?
All 93C66CT-I/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-I/ST meets industry standards.
7.What is the process for return or replacement of 93C66CT-I/ST?
All 93C66CT-I/ST units undergo pre-shipment inspection (PSI). If there is an issue with 93C66CT-I/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-I/ST part is unused and in its original packaging.
Return procedure for 93C66CT-I/ST:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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