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Microchip Technology 93C66C-I/ST
- Part No.:
- 93C66C-I/ST
- Manufacturer:
- Microchip Technology
- Category:
- Memory
- Package:
- 8-TSSOP (0.173", 4.40mm Width)
- Datasheet:
-
93C66C-I/ST.pdf
- Description:
- IC EEPROM 4KBIT MICROWIRE 8TSSOP
- Quantity:
- Payment:
- Shipping:
Inventory:2,601
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Product details
Overview
93C66C-I/ST from Microchip Technology Inc. is a 4 Kbit serial EEPROM with Microwire-compatible 3-wire interface, ORG-pin-selectable 8-/16-bit word organization, and industrial temperature range (–40°C to +85°C). It operates from 4.5V to 5.5V, supports self-timed erase/write cycles (2 ms typical), delivers >200 years data retention, and features Ready/Busy status signaling via DO pin - used in embedded system configuration storage and calibration data logging.
For engineers reviewing the 93C66C-I/ST datasheet, 93C66C-I/ST pinout, 93C66C-I/ST application, or 93C66C-I/ST equivalent, key selection criteria include VCC operating range (4.5–5.5 V), ORG-pin-dependent memory width (x8/x16), industrial-grade thermal performance, TSSOP-8 package compatibility, and Microwire protocol timing compliance at up to 3 MHz.
Technical Context
The 93C66C-I/ST implements a synchronous serial interface using CS, CLK, and DI/DO signals with start-bit detection and opcode-driven command execution. Its ORG pin directly controls internal address/data width mapping: logic high selects 256 × 16-bit mode; logic low selects 512 × 8-bit mode.
It uses self-timed erase/write cycles (2 ms max for 93C versions), automatic ERAL before WRAL, power-on/off data protection, and EWEN/EWDS lockout for write safety. Ready/Busy status is actively signaled on DO during programming, requiring CS high ≥250 ns after TCSL to sample.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Memory size | 4 Kbit (512 × 8 or 256 × 16, selectable via ORG pin) |
| VCC range | 4.5 V to 5.5 V - ensures compatibility with 5 V logic systems and rejects brown-out below 3.8 V |
| Interface | Microwire-compatible 3-wire serial (CS, CLK, DI/DO) - requires no additional level-shifting in 5 V microcontroller designs |
| Write cycle time | 2 ms maximum - enables fast firmware updates without blocking host MCU for extended periods |
| Data retention | >200 years at 85°C - guarantees long-term calibration storage in unpowered industrial equipment |
| Endurance | 1,000,000 erase/write cycles - supports frequent recalibration or event logging in field-deployed devices |
| Temperature range | –40°C to +85°C (Industrial grade) - validated for operation in factory automation and motor control enclosures |
Pinout & Package
93C66C-I/ST is packaged in an 8-lead TSSOP (ST) with 0.65 mm pitch, JEDEC MO-153 compliant, Pb-free Matte Tin finish, and exposed pad optional grounding per Microchip packaging spec.
| 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 allows ongoing write completion |
| CLK | Serial Clock | Synchronizes all data transfers on rising edge; stoppable mid-sequence; no clock required during self-timed write |
| DI | Data Input | Accepts start bit, opcode, address, and write data; shares net with DO only with series resistor to prevent bus conflict |
| DO | Data Output / Status | Outputs read data or Ready/Busy signal (low = busy); enters High-Z on CS falling edge |
| VSS | Ground | Reference for all I/O and internal circuitry; must be low-impedance connection to minimize noise coupling |
| ORG | Organization Control | Logic high → 256 × 16-bit mode; logic low → 512 × 8-bit mode; must be statically tied, not floated |
| NC | No Connection | Pin 7 in TSSOP - internally unconnected; must remain unconnected on PCB |
| VCC | Power Supply | 4.5–5.5 V supply; internal POR triggers at 3.8 V; powers EEPROM array and interface logic |
Key Features
| Feature | Design Value |
|---|---|
| ORG-pin word-size selection | Enables single BOM part to support both 8-bit and 16-bit host MCU interfaces without redesign |
| Self-timed erase/write | Eliminates need for external timing control or polling delay loops in firmware |
| Automatic ERAL before WRAL | Guarantees full-array write success without separate erase command in bootloaders |
| Ready/Busy status on DO | Allows real-time progress monitoring during programming without dedicated status register access |
| EWEN/EWDS write protection | Prevents accidental overwrites during power transients or software faults by defaulting to disabled state at power-up |
Applications
| Industrial PLC Configuration Storage | Automotive ECU Calibration Data |
|---|---|
Use Scenario: Storing I/O mapping, PID tuning parameters, and alarm thresholds in programmable logic controllers deployed in manufacturing lines. IC Role / Device Role / Timing Role: Nonvolatile configuration register accessed infrequently during commissioning or maintenance; retains values across power cycles and ambient temperature swings. Use Value: 200-year data retention and 1M endurance ensure parameter integrity over full equipment lifetime without battery backup. | Use Scenario: Holding sensor offset corrections, fuel trim tables, and diagnostic fault codes in engine control units operating under hood temperatures up to 85°C. IC Role / Device Role / Timing Role: Calibration memory mapped to microcontroller SPI/Microwire peripheral; accessed during startup and periodic self-test routines. Use Value: ORG-pin flexibility allows reuse across 8-bit legacy ECUs and 16-bit upgraded platforms, reducing qualification effort. |
| Medical Device Setup Profiles | Smart Meter Firmware Parameters |
Use Scenario: Saving user-defined therapy settings, alarm limits, and device ID in portable infusion pumps and dialysis monitors. IC Role / Device Role / Timing Role: Secure, tamper-resistant storage for regulatory-critical operational parameters; accessed only during setup or service mode. Use Value: Power-on/off data protection and EWDS default prevent corruption during unexpected AC loss or battery swap events. | Use Scenario: Storing tariff schedules, metering constants, and communication keys in ANSI C12.19-compliant electricity meters. IC Role / Device Role / Timing Role: Field-updatable parameter bank isolated from main flash; written during firmware update or utility command injection. Use Value: 3 MHz clock support enables fast parameter loading during AMI network rollouts without extending meter boot time. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar serial EEPROM applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| 93LC66C-I/ST | Wider VCC range (2.5–5.5 V); same pinout, ORG function, and instruction set | Supports 3.3 V and 5 V systems; lacks 93C66C's 4.5–5.5 V optimized noise immunity | Select when mixed-voltage board design or lower-power sleep modes are required |
| AT25040B-SSHL-T | SPI interface (4-wire), 4 Kbit, 1.8–5.5 V; no ORG pin; different command set and timing | Requires SPI-capable MCU; no hardware word-width selection; higher write latency (5 ms) | Select when migrating from legacy Microwire to standardized SPI infrastructure |
Compared with 93LC66C-I/ST, the 93C66C-I/ST offers tighter VCC tolerance and enhanced noise margin for 5 V industrial buses, while AT25040B-SSHL-T trades Microwire compatibility for broader voltage support and industry-standard SPI integration.
Availability
93C66C-I/ST is available at Aetrix Electronics and suitable for industrial PLC configuration storage, automotive ECU calibration data, and medical device setup profiles requiring stable component supply across multi-year production cycles.
Supply support for 93C66C-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 components, and memory solutions, headquartered in Chandler, Arizona, with global design and manufacturing operations.
The 93C66C-I/ST belongs to Microchip's legacy 93XX serial EEPROM family, designed specifically for cost-sensitive, low-power, nonvolatile memory applications in industrial control, automotive subsystems, and consumer electronics where Microwire protocol compatibility and hardware-configurable word width are critical.
FAQ
What is the function of the ORG pin on the 93C66C-I/ST?
The ORG pin on the 93C66C-I/ST selects memory organization: logic high configures 256 × 16-bit mode; logic low configures 512 × 8-bit mode. It must be statically tied to VCC or VSS - floating is undefined. This pin enables one 93C66C-I/ST part number to serve both 8-bit and 16-bit host interfaces without changing firmware or layout.
Does the 93C66C-I/ST require external pull-up resistors on its I/O pins?
The 93C66C-I/ST does not require external pull-ups on CS, CLK, or DI for basic operation, as internal weak pull-downs are absent and bus behavior depends on host drive strength. However, DO requires external pull-up if used in open-drain status-check mode, and a series resistor (1–10 kΩ) is recommended when DI and DO share a bidirectional net to prevent bus conflict during read dummy-zero cycles.
What is the minimum VCC voltage at which the 93C66C-I/ST guarantees data retention during power loss?
The 93C66C-I/ST incorporates power-on/off data protection that inhibits all operations when VCC falls below 3.8 V. Below this threshold, write/erase commands are blocked and existing memory contents remain intact. This ensures reliable data retention during brown-out conditions common in industrial 5 V rails, and is a hard specification - not a typical value.
Can the 93C66C-I/ST be used in place of the 93C66A-I/ST without hardware changes?
No - the 93C66C-I/ST cannot replace the 93C66A-I/ST without verifying ORG pin handling. The 93C66A-I/ST has no ORG pin (internally fixed x8 mode) and pin 6 is NC, whereas the 93C66C-I/ST uses pin 6 as functional ORG. Direct substitution would leave ORG floating or shorted, causing undefined behavior. Layout and schematic must allocate ORG routing for 93C66C-I/ST.
How does the Ready/Busy status work on the DO pin of the 93C66C-I/ST?
During erase or write operations, the DO pin of the 93C66C-I/ST outputs Ready/Busy status: logic low indicates programming in progress; logic high indicates completion. To read status, CS must be brought high for ≥250 ns after TCSL (minimum CS low time); DO then reflects status until next instruction. Issuing a Start bit followed by CS low clears the status flag.
93C66C-I/ST Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Microchip Technology
- Series:
- -
- Package/Case:
- 8-TSSOP (0.173", 4.40mm Width)
- Packaging:
- Tube
- 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
93C66C-I/ST FAQ
1.How can I place an order for 93C66C-I/ST through Aetrix?
Please submit a Request for Quotation (RFQ) for 93C66C-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 93C66C-I/ST reliable?
The price and inventory of 93C66C-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 93C66C-I/ST is usually 5 days.
3.What payment methods are accepted for 93C66C-I/ST?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for 93C66C-I/ST transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for 93C66C-I/ST?
93C66C-I/ST orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your 93C66C-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 93C66C-I/ST?
For technical support, including 93C66C-I/ST datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your 93C66C-I/ST requirements.
6.How does Aetrix verify that 93C66C-I/ST is sourced from the original manufacturer or authorized distributors?
All 93C66C-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 93C66C-I/ST meets industry standards.
7.What is the process for return or replacement of 93C66C-I/ST?
All 93C66C-I/ST units undergo pre-shipment inspection (PSI). If there is an issue with 93C66C-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 93C66C-I/ST part is unused and in its original packaging.
Return procedure for 93C66C-I/ST:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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