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Microchip Technology 93C66A-I/MS
- Part No.:
- 93C66A-I/MS
- Manufacturer:
- Microchip Technology
- Category:
- Memory
- Package:
- 8-TSSOP, 8-MSOP (0.118", 3.00mm Width)
- Datasheet:
-
93C66A-I/MS.pdf
- Description:
- IC EEPROM 4KBIT MICROWIRE 8MSOP
- Quantity:
- Payment:
- Shipping:
Inventory:3,834
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Product details
Overview
93C66A-I/MS from Microchip Technology Inc. is a 4 Kbit (512 × 8-bit) low-voltage serial EEPROM with Microwire-compatible 3-wire interface, 4.5–5.5 V supply range, and Industrial temperature grade (−40°C to +85°C). It features self-timed erase/write cycles, automatic ERAL before WRAL, power-on/off data protection, and Ready/Busy status signaling via DO pin - used in embedded system configuration storage, sensor calibration retention, and industrial controller parameter backup.
For engineers reviewing the 93C66A-I/MS datasheet, 93C66A-I/MS pinout, 93C66A-I/MS application, or 93C66A-I/MS equivalent, key selection considerations include its fixed 8-bit organization (no ORG pin), MSOP-8 package footprint, 2 ms typical write cycle time, 1 million endurance cycles, and compatibility with legacy Microwire controllers requiring CS/CLK/DI/DO timing compliance per DS21795E.
Technical Context
The 93C66A-I/MS implements a synchronous serial interface with start-bit detection, opcode-driven instruction 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.
Timing behavior is defined by strict AC parameters: max 3 MHz clock frequency at VCC ≥ 4.5 V, 250 ns minimum CS low time between instructions, and 2 ms typical erase/write cycle (TWC) - significantly faster than 6 ms for 93AA/93LC versions. Power management includes <1 µA standby current and VCC brown-out protection triggering at 3.8 V.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Memory Size | 4 Kbit (512 × 8-bit); fixed x8 organization eliminates need for ORG pin routing or level-shifting logic. |
| Supply Voltage | 4.5–5.5 V; brown-out lockout activates below 3.8 V to prevent spurious writes during power ramp-up/down. |
| Write Cycle Time | 2 ms typical (TWC); enables faster firmware updates and parameter saves vs. 6 ms in AA/LC variants. |
| Endurance | 1,000,000 erase/write cycles; supports long-term field deployment in industrial logging and calibration applications. |
| Data Retention | 200 years at +25°C; ensures configuration integrity over product lifetime without refresh circuitry. |
| Interface | Microwire-compatible 3-wire serial (CS, CLK, DI/DO); requires no additional protocol translation for legacy MCU peripherals. |
| Temperature Range | Industrial: −40°C to +85°C; validated across full range for use in factory automation and outdoor equipment. |
Pinout & Package
8-pin MSOP (Micro Small Outline Package), 3.0 mm × 3.0 mm body, 0.65 mm pitch, exposed pad optional (VSS or floating).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 CS | Chip Select | Active-high enable; must be held low ≥250 ns between commands to reset internal state machine. |
| 2 CLK | Serial Clock | Positive-edge synchronous timing; supports stop/resume mid-transfer and up to 3 MHz operation at 4.5–5.5 V. |
| 3 DI | Data Input | Accepts start bit, opcode, address, and data; high-impedance when CS low to avoid bus contention. |
| 4 DO | Data Output / Status | Outputs read data or Ready/Busy (low = busy); enters High-Z on CS falling edge to isolate bus. |
| 5 VSS | Ground | Reference for all I/O and internal logic; connects to exposed pad if used for thermal dissipation. |
| 6 NC | No Connection | Internally unconnected; must remain floating or tied to VSS per layout best practice. |
| 7 ORG | Organization Select | No internal connection on 'A' devices; omitted from functional logic - not routed on PCB. |
| 8 VCC | Power Supply | 4.5–5.5 V input; includes internal voltage detector (VPOR = 3.8 V) for automatic write inhibition during undervoltage. |
Key Features
| Feature | Design Value |
|---|---|
| Self-timed Erase/Write | Eliminates external timing control - internal logic manages auto-erase-before-write and completion signaling via DO pin. |
| Automatic ERAL before WRAL | Ensures full-array write reliability without requiring separate erase command in firmware sequence. |
| Power-On/Off Data Protection | Hardware-level VCC monitoring prevents corruption during brown-out or power cycling - no software intervention needed. |
| Ready/Busy Status Signal | DO pin doubles as status indicator; allows polling-based wait loops instead of fixed delays, improving system responsiveness. |
| Sequential Read Function | Enables burst reads across consecutive addresses with single CS assertion - reduces transaction overhead in configuration loading. |
Applications
| Industrial PLC Configuration Storage | Automotive ECU Calibration Data |
|---|---|
Use Scenario: Storing I/O mapping tables, PID tuning parameters, and alarm thresholds in programmable logic controllers deployed in manufacturing lines. IC Role / Device Role / Timing Role: Nonvolatile configuration register accessed during boot and runtime via Microwire interface; supports infrequent writes but frequent reads. Use Value: 200-year data retention and 1M endurance ensure parameter integrity across 10+ year service life without battery backup. | Use Scenario: Holding sensor offset corrections and actuator trim values in engine control units operating under wide thermal cycling. IC Role / Device Role / Timing Role: Calibration memory mapped to microcontroller's serial peripheral; accessed during startup and periodic self-test routines. Use Value: −40°C to +85°C industrial rating matches under-hood ambient requirements; 2 ms write time minimizes test duration impact. |
| Medical Device Safety Settings | Smart Meter Firmware Parameters |
Use Scenario: Securing critical safety limits (e.g., maximum infusion rate, temperature cutoffs) in portable diagnostic equipment. IC Role / Device Role / Timing Role: Tamper-resistant configuration store with hardware write protection (EWDS/EWEN) and VCC-dependent lockout. Use Value: Power-on data protection prevents unsafe defaults during cold start; 4.5–5.5 V range aligns with regulated 5 V rails in medical power supplies. | Use Scenario: Storing tariff schedules, metering constants, and communication keys in utility smart meters with 15+ year field life. IC Role / Device Role / Timing Role: Long-term parameter archive accessed via isolated UART-to-Microwire bridge; written during firmware updates or utility provisioning. Use Value: Pb-free MSOP-8 package meets RoHS compliance for global deployment; 1M endurance supports decades of firmware revision cycles. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar serial EEPROM applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| 93LC66A-I/MS | 2.5–5.5 V supply range; 6 ms write cycle; same 512×8 organization and MSOP-8 package. | Supports wider VCC range including 3.3 V systems; slower write impacts high-frequency parameter updates. | Select when interfacing with 3.3 V MCUs or where extended voltage margin outweighs speed penalty. |
| AT25040B-MAU-10 | SPI interface (4-wire), 1.8–5.5 V, 5 ms write time, same 4 Kbit density and SOIC-8/MSOP-8 options. | Requires SPI master instead of Microwire; broader voltage support but different protocol stack integration. | Choose for designs already using SPI peripherals or needing lower 1.8 V operation; verify timing compatibility with existing driver code. |
Compared with 93LC66A-I/MS, the 93C66A-I/MS offers faster 2 ms writes and tighter 4.5–5.5 V regulation - ideal for 5 V-only industrial systems prioritizing update speed. Versus AT25040B-MAU-10, it retains Microwire compatibility for legacy controller reuse but lacks sub-4.5 V operation.
Availability
93C66A-I/MS is available at Aetrix Electronics and suitable for industrial PLC configuration storage, automotive ECU calibration data retention, and medical device safety settings requiring stable component supply across multi-year production cycles.
Supply support for 93C66A-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 nonvolatile memory solutions, headquartered in Chandler, Arizona.
The 93C66A-I/MS belongs to Microchip's legacy 93XX serial EEPROM family, designed specifically for cost-sensitive, low-power embedded systems requiring robust Microwire-compatible configuration storage with hardware data protection.
FAQ
What is the memory organization of the 93C66A-I/MS?
The 93C66A-I/MS has a fixed 512 × 8-bit organization with no ORG pin - unlike 'C' variants, it does not support x16 mode. This simplifies PCB layout by eliminating ORG routing and external pull-up/pull-down resistors, making it ideal for space-constrained designs where 8-bit data width suffices.
Does the 93C66A-I/MS require an external ORG pin connection?
No, the 93C66A-I/MS does not require an external ORG pin connection because it is an 'A' variant device with fixed 8-bit organization. Pin 7 (ORG) is internally unconnected (NC) and must be left floating or tied to VSS per Microchip's layout guidelines - no logic level assignment is needed or supported.
What is the typical write cycle time for the 93C66A-I/MS?
The typical write cycle time for the 93C66A-I/MS is 2 ms (TWC), as specified in DS21795E Table 1-2, A13. This is half the 6 ms required by 93AA66A and 93LC66A variants, enabling faster parameter updates in time-critical industrial applications while maintaining full 4.5–5.5 V operational compliance.
How does the 93C66A-I/MS handle power loss during a write operation?
The 93C66A-I/MS incorporates hardware-level power-loss protection: its internal voltage detector triggers at 3.8 V (VPOR), automatically inhibiting all erase/write operations when VCC drops below this threshold. This prevents partial writes and data corruption without requiring external supervisor ICs or firmware intervention.
Is the 93C66A-I/MS RoHS compliant and lead-free?
Yes, the 93C66A-I/MS is Pb-free and RoHS compliant, featuring a Matte Tin (Sn) finish per Microchip's packaging specification. The MSOP-8 package meets JEDEC standards for lead-free assembly, supporting reflow profiles up to 260°C and ensuring compatibility with modern environmentally regulated manufacturing processes.
93C66A-I/MS Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Microchip Technology
- Series:
- -
- Package/Case:
- 8-TSSOP, 8-MSOP (0.118", 3.00mm 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
- Memory Interface:
- Microwire
- Clock Frequency:
- 2 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
93C66A-I/MS FAQ
1.How can I place an order for 93C66A-I/MS through Aetrix?
Please submit a Request for Quotation (RFQ) for 93C66A-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 93C66A-I/MS reliable?
The price and inventory of 93C66A-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 93C66A-I/MS is usually 5 days.
3.What payment methods are accepted for 93C66A-I/MS?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for 93C66A-I/MS transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for 93C66A-I/MS?
93C66A-I/MS orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your 93C66A-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 93C66A-I/MS?
For technical support, including 93C66A-I/MS datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your 93C66A-I/MS requirements.
6.How does Aetrix verify that 93C66A-I/MS is sourced from the original manufacturer or authorized distributors?
All 93C66A-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 93C66A-I/MS meets industry standards.
7.What is the process for return or replacement of 93C66A-I/MS?
All 93C66A-I/MS units undergo pre-shipment inspection (PSI). If there is an issue with 93C66A-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 93C66A-I/MS part is unused and in its original packaging.
Return procedure for 93C66A-I/MS:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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