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Microchip Technology 93C66CT-I/MS
- Part No.:
- 93C66CT-I/MS
- Manufacturer:
- Microchip Technology
- Category:
- Memory
- Package:
- 8-TSSOP, 8-MSOP (0.118", 3.00mm Width)
- Datasheet:
-
93C66CT-I/MS.pdf
- Description:
- IC EEPROM 4KBIT MICROWIRE 8MSOP
- Quantity:
- Payment:
- Shipping:
Inventory:1,681
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Product details
Overview
93C66CT-I/MS 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 over 4.5–5.5 V, supports Microwire-compatible 3-wire serial interface (CS/CLK/DI/DO), and delivers 1,000,000 erase/write cycles with >200-year data retention. Used in industrial control panels for configuration parameter storage.
For engineers reviewing the 93C66CT-I/MS datasheet, 93C66CT-I/MS pinout, 93C66CT-I/MS application, or 93C66CT-I/MS equivalent, key selection criteria include its 4.5–5.5 V supply range, MSOP-8 package, 8-bit x512 organization, ERAL/WRAL auto-erase support, and Ready/Busy status signaling via DO pin.
Technical Context
The 93C66CT-I/MS implements a synchronous Microwire-compatible serial interface with start-bit detection, opcode-driven command set (READ/WRITE/ERASE/ERAL/WRAL/EWEN/EWDS), and self-timed erase/write cycles initiated by CS falling edge (for 93C versions). It features power-on/off data protection and automatic ERAL before WRAL execution.
Memory organization is fixed at 512 × 8-bit (no ORG pin functionality); the 'T' suffix denotes Industrial temperature grade (−40°C to +85°C), and '/MS' confirms 8-lead MSOP packaging with Matte Tin (Pb-free) finish. VCC voltage detect threshold is 3.8 V for POR lockout.
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 operating range | 4.5 V to 5.5 V - ensures compatibility with 5 V logic systems and prevents operation below 3.8 V POR threshold |
| Clock frequency | Up to 3 MHz at 4.5–5.5 V - enables fast serial access without external timing constraints |
| Write cycle time | 2 ms typical - defines minimum interval between write commands; supports rapid firmware parameter updates |
| Data retention | >200 years at 25°C - guarantees long-term storage integrity in unpowered industrial environments |
| Endurance | 1,000,000 erase/write cycles - supports frequent calibration or logging operations over product lifetime |
| Interface protocol | Microwire-compatible 3-wire serial (CS/CLK/DI/DO) - minimal GPIO usage on host MCU, no address bus needed |
Pinout & Package
8-lead MSOP (150 mil) package with exposed pad (optional VSS connection), Pb-free Matte Tin finish, pin 1 marked by laser dot. Pinout matches standard MSOP-8 footprint per Microchip DS21795E.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 (CS) | Chip Select | Active-high enable; must be held ≥250 ns low between instructions; deselects device into standby mode |
| 2 (CLK) | Serial Clock | Synchronizes all data transfers; rising edge clocks in opcodes, addresses, and data; stoppable mid-transfer |
| 3 (DI) | Data Input | Receives start bit, instruction opcodes, memory addresses, and write data; requires pull-up for robust start detection |
| 4 (DO) | Data Output / Status | Outputs read data or Ready/Busy status (low = busy); high-Z when not active; requires CS high ≥250 ns to sample status |
| 5 (VSS) | Ground | Reference return path for all signals; exposed pad may be connected to VSS for thermal/mechanical stability |
| 6 (VCC) | Power Supply | 4.5–5.5 V supply; internal POR circuit locks operation below 3.8 V to prevent corruption |
| 7 (NC) | No Connect | Internally unconnected; must be left floating or tied to VSS/VCC per board layout best practices |
| 8 (ORG) | Organization Select | No internal connection on 93C66A/B variants - pin is NC and must not be driven; differs from C-series devices |
Key Features
| Feature | Design Value |
|---|---|
| Self-timed erase/write cycles | Eliminates need for external timing control - host MCU only monitors DO pin for completion |
| Automatic ERAL before WRAL | Guarantees full array erase prior to bulk write, preventing partial-data corruption during firmware update sequences |
| Power-on/off data protection | Hardware-level lockout below 3.8 V VCC prevents inadvertent writes during brown-out or power ramp conditions |
| Ready/Busy status on DO | Enables polling-based flow control without interrupt lines - reduces MCU resource usage in cost-sensitive designs |
| Industry-standard 3-wire serial I/O | Minimizes PCB routing complexity and pin count vs. SPI/I²C; compatible with legacy Microwire controllers |
Applications
| Industrial Sensor Calibration Storage | Embedded System Configuration Memory |
|---|---|
Use Scenario: Storing factory-calibrated sensor offset/gain coefficients in HVAC temperature sensors deployed in commercial buildings. IC Role / Device Role / Timing Role: Nonvolatile parameter storage accessed at power-up; 2 ms write latency acceptable due to infrequent recalibration. Use Value: Ensures measurement accuracy across 20+ year building lifecycle without battery backup or external NVRAM. | Use Scenario: Holding user-configurable settings (display brightness, language, network ID) in medical infusion pump UI modules. IC Role / Device Role / Timing Role: Serial configuration EEPROM interfaced to 8-bit MCU via 3-wire bus; accessed during boot and settings save. Use Value: Reduces BOM cost vs. flash-based alternatives while meeting IEC 62304 Class C data integrity requirements. |
| Automotive Body Control Module (BCM) Trim Settings | Programmable Power Supply Configuration |
Use Scenario: Retaining driver seat/mirror position presets in automotive BCMs operating across −40°C to +85°C ambient. IC Role / Device Role / Timing Role: Industrial-grade EEPROM storing 8-bit trim values; accessed via dedicated MCU GPIOs with CS/CLK/DI/DO routing. Use Value: Meets AEC-Q100 stress test requirements for data retention and endurance under thermal cycling. | Use Scenario: Storing output voltage/current limits and startup sequencing parameters in programmable DC-DC modules for telecom equipment. IC Role / Device Role / Timing Role: Configuration memory mapped to power controller's serial interface; written once during manufacturing calibration. Use Value: Enables field-reprogrammability of power profiles without firmware update, reducing service downtime. |
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/MS | 2.5–5.5 V VCC range; same 512×8 organization; includes ORG pin (NC on this variant) | Supports wider supply range including 3.3 V systems; lacks 4.5 V minimum, so unsuitable for strict 5 V-only rails | Select when system operates at 3.3 V or mixed-voltage domains; verify POR behavior at lower VCC |
| AT25040B-MAU-1.8 | SPI interface (4-wire), 1.8–5.5 V, 512×8, 20 MHz max clock, 5 ms write time | Requires additional CS line and different command set; higher speed but longer write latency than 93C66CT-I/MS | Choose for SPI-native platforms needing faster clock rates; accept added pin count and software driver changes |
Compared with 93LC66AT-I/MS, the 93C66CT-I/MS offers tighter VCC regulation (4.5–5.5 V) and faster 2 ms writes, making it optimal for stable 5 V industrial rails. Versus AT25040B-MAU-1.8, it uses simpler 3-wire Microwire signaling but trades off maximum clock speed for deterministic low-pin-count integration.
Availability
93C66CT-I/MS is available at Aetrix Electronics and suitable for industrial control systems, medical device configuration storage, and automotive body electronics requiring stable component supply across extended temperature ranges and long production lifecycles.
Supply support for 93C66CT-I/MS 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 design and manufacturing operations.
The 93Cxx series was engineered specifically for cost-sensitive, low-power serial EEPROM applications in industrial and automotive systems where reliability, long data retention, and simple 3-wire interfacing are critical design requirements.
FAQ
What is the function of the ORG pin on the 93C66CT-I/MS?
The ORG pin is not functional on the 93C66CT-I/MS - it is internally unconnected (NC) as confirmed by the Device Selection Table and Pin Function Table in DS21795E. This part belongs to the 'A' variant family (93C66A), which has fixed 8-bit organization and no ORG pin capability. Driving ORG on 93C66CT-I/MS has no effect and should be left floating or tied to VSS per layout guidelines.
Does the 93C66CT-I/MS support 3.3 V operation?
No, the 93C66CT-I/MS does not support 3.3 V operation. Its specified VCC range is strictly 4.5 V to 5.5 V, and its power-on reset (POR) circuit activates lockout below 3.8 V. Attempting to operate at 3.3 V will prevent initialization and may cause unpredictable read/write behavior. For 3.3 V systems, consider the 93LC66AT-I/MS or 93AA66AT-I/MS instead.
How is Ready/Busy status monitored on the 93C66CT-I/MS?
Ready/Busy status is monitored by sampling the DO pin after bringing CS high for ≥250 ns following instruction initiation. During erase/write cycles, DO = low indicates ongoing operation; DO = high indicates completion. The status is cleared if a Start bit is detected followed by CS low. No external pull-up is required on DO, as the device drives actively during status reporting.
What is the maximum clock frequency supported by the 93C66CT-I/MS?
The 93C66CT-I/MS supports up to 3 MHz clock frequency when VCC is between 4.5 V and 5.5 V, as specified in Table 1-2 (A1 parameter). At this rate, READ and WRITE instructions complete in 20 clock cycles (≈6.7 µs transfer time), excluding self-timed 2 ms programming latency. Clock timing margins (TCKH/TCKL) must meet minimum 200 ns/100 ns requirements respectively.
Is the 93C66CT-I/MS RoHS compliant and Pb-free?
Yes, the 93C66CT-I/MS is Pb-free and RoHS compliant, with Matte Tin (Sn) finish on all leads as stated in the Features section of DS21795E. The '/MS' suffix explicitly denotes the 8-lead MSOP package with this environmentally compliant plating. Full compliance documentation is available in Microchip's official packaging specification and material declarations.
93C66CT-I/MS Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Microchip Technology
- Series:
- -
- Package/Case:
- 8-TSSOP, 8-MSOP (0.118", 3.00mm 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-MSOP
93C66CT-I/MS FAQ
1.How can I place an order for 93C66CT-I/MS through Aetrix?
Please submit a Request for Quotation (RFQ) for 93C66CT-I/MS 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/MS reliable?
The price and inventory of 93C66CT-I/MS 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/MS is usually 5 days.
3.What payment methods are accepted for 93C66CT-I/MS?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for 93C66CT-I/MS transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for 93C66CT-I/MS?
93C66CT-I/MS orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your 93C66CT-I/MS 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/MS?
For technical support, including 93C66CT-I/MS datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your 93C66CT-I/MS requirements.
6.How does Aetrix verify that 93C66CT-I/MS is sourced from the original manufacturer or authorized distributors?
All 93C66CT-I/MS 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/MS meets industry standards.
7.What is the process for return or replacement of 93C66CT-I/MS?
All 93C66CT-I/MS units undergo pre-shipment inspection (PSI). If there is an issue with 93C66CT-I/MS, 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/MS part is unused and in its original packaging.
Return procedure for 93C66CT-I/MS:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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