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Microchip Technology 93C66B-I/ST
- Part No.:
- 93C66B-I/ST
- Manufacturer:
- Microchip Technology
- Category:
- Memory
- Package:
- 8-TSSOP (0.173", 4.40mm Width)
- Datasheet:
-
93C66B-I/ST.pdf
- Description:
- IC EEPROM 4KBIT MICROWIRE 8TSSOP
- Quantity:
- Payment:
- Shipping:
Inventory:1,540
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Product details
Overview
93C66B-I/ST from Microchip Technology Inc. is a 4 Kbit, 256 x 16-bit organization serial EEPROM with Microwire-compatible 3-wire interface, operating at 4.5–5.5 V, rated for industrial temperature (–40°C to +85°C), and housed in an 8-lead SOIC package. 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 and calibration data retention.
For engineers reviewing the 93C66B-I/ST datasheet, 93C66B-I/ST pinout, 93C66B-I/ST application, or 93C66B-I/ST equivalent, key selection criteria include its fixed 16-bit word size (no ORG pin), 4.5–5.5 V supply range, industrial-grade temperature rating, SOIC-8 packaging, and Microwire protocol compatibility with CS/CLK/DI/DO timing constraints.
Technical Context
The 93C66B-I/ST implements a synchronous serial Microwire interface with dedicated 16-bit memory organization - no ORG pin required. Its command set includes READ, WRITE, ERASE, ERAL, WRAL, EWEN, and EWDS, all executed via rising-edge clocked bit streams on DI, with status reported on DO.
Write operations are initiated by the rising edge of CLK on the final data bit (93C-series behavior), not CS falling edge. VCC must be ≥4.5 V for ERAL and WRAL execution, and internal power-on reset circuitry inhibits programming below 3.8 V to ensure data integrity during brown-out conditions.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Memory Size | 4 Kbit (256 × 16-bit) - supports compact firmware parameter storage without external word-width logic. |
| VCC Range | 4.5 V to 5.5 V - compatible with legacy 5 V systems; excludes low-voltage operation below 4.5 V. |
| Interface | Microwire 3-wire serial (CS, CLK, DI/DO) - requires only three MCU GPIOs and no I²C pull-ups. |
| Write Cycle Time | 2 ms typical - enables fast field updates without blocking host controller for extended periods. |
| Data Retention | 200 years - ensures long-term reliability in unpowered storage for industrial equipment logs. |
| Endurance | 1,000,000 erase/write cycles - suitable for applications requiring frequent recalibration or event logging. |
| Temperature Range | –40°C to +85°C (Industrial) - validated for use in factory automation, motor drives, and HVAC controls. |
Pinout & Package
8-lead SOIC (ST) package with standard pinout: Pin 1 = CS, Pin 2 = CLK, Pin 3 = DI, Pin 4 = DO, Pin 5 = VSS, Pin 6 = NC, Pin 7 = NC, Pin 8 = VCC. No ORG pin - fixed 16-bit organization.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| CS | Chip Select | Active-high enable; device enters Standby when low, but completes ongoing write before sleeping. |
| CLK | Serial Clock | Rising-edge synchronized I/O; clock can pause mid-transfer without corruption. |
| DI | Data Input | Accepts Start bit, opcodes, addresses, and write data; shares no internal path with DO. |
| DO | Data Output / Status | Outputs read data or Ready/Busy (low = busy); high-Z when CS low or during non-read states. |
| VSS | Ground | Reference for all digital and analog functions; must be low-impedance for stable erase/write timing. |
| NC (Pins 6 & 7) | No Internal Connection | Unbonded; must remain floating - no routing or PCB traces required. |
| VCC | Power Supply | 4.5–5.5 V only; internal POR triggers at 3.8 V - prevents partial writes during power ramp-up. |
Key Features
| Feature | Design Value |
|---|---|
| Self-timed erase/write | Eliminates need for external timing control - host MCU polls DO for completion instead of fixed delays. |
| Automatic ERAL before WRAL | Guarantees full-array readiness before bulk write - prevents partial overwrites and data corruption. |
| Power-on/off data protection | Hardware-level lockout below 3.8 V - no software safeguards needed to prevent brown-out writes. |
| Ready/Busy status on DO | Enables efficient polling without additional pins - reduces BOM count versus dedicated BUSY output ICs. |
| Sequential read mode | Allows continuous address increment with single CS assertion - cuts SPI transaction overhead by ~40% vs. random reads. |
Applications
| Industrial Sensor Calibration | Motor Drive Configuration |
|---|---|
Use Scenario: Storing factory-trimmed offset/gain coefficients for analog sensor front-ends in PLC modules. IC Role / Device Role / Timing Role: Nonvolatile parameter register accessed at power-up and during field recalibration routines. Use Value: 256 × 16-bit layout matches typical 16-bit ADC calibration tables; 1M endurance supports >10 years of service recalibrations. | Use Scenario: Holding motor commutation angles, current limits, and PID gains in brushless DC drive controllers. IC Role / Device Role / Timing Role: Configuration store loaded at boot; updated during commissioning or adaptive tuning sessions. Use Value: 2 ms write time allows real-time gain updates without interrupting motion control loops. |
| Medical Device Settings | Energy Meter Firmware Patch Storage |
Use Scenario: Retaining user-prescribed therapy parameters and audit logs in portable infusion pumps. IC Role / Device Role / Timing Role: Secure settings vault with hardware write-protection (EWEN/EWDS) and brown-out immunity. Use Value: 200-year data retention meets FDA 510(k) archival requirements; 4.5–5.5 V range aligns with medical-grade 5 V rails. | Use Scenario: Storing field-deployed firmware patches for smart electricity meters with limited flash update cycles. IC Role / Device Role / Timing Role: Secondary code repository enabling safe rollback if main flash update fails. Use Value: WRAL instruction allows atomic full-image writes; ERAL-before-WRAL prevents partial patch corruption. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar serial EEPROM applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| 93LC66B-I/ST | 2.5–5.5 V supply range; same 256 × 16-bit organization, SOIC-8 pinout, and Microwire interface. | Supports wider voltage range including 3.3 V systems; lacks 4.5 V minimum - unsuitable for strict 5 V-only designs. | Select when migrating to mixed-voltage boards or adding 3.3 V MCU compatibility. |
| AT25040B-MAHL-T | SPI interface (4-wire), 512 × 8-bit organization, 1.8–5.5 V, same SOIC-8 package. | Requires separate SI/SO lines and chip-select management; incompatible instruction set and timing model. | Choose only if existing design uses SPI peripherals and 8-bit word access suffices. |
Compared with 93LC66B-I/ST, the 93C66B-I/ST offers tighter VCC tolerance ideal for legacy 5 V systems but sacrifices low-voltage flexibility; versus AT25040B-MAHL-T, it retains Microwire simplicity and 16-bit efficiency but cannot interoperate with SPI hosts without protocol translation.
Availability
93C66B-I/ST is available at Aetrix Electronics and suitable for industrial sensor calibration, motor drive configuration, and medical device settings requiring stable component supply across multi-year production cycles.
Supply support for 93C66B-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 manufacturing and support infrastructure.
The 93Cxx EEPROM product line targets cost-sensitive, space-constrained embedded systems needing reliable nonvolatile storage with minimal pin count and deterministic timing - especially where Microwire compatibility and industrial temperature operation are mandatory.
FAQ
What is the memory organization of the 93C66B-I/ST?
The 93C66B-I/ST has a fixed 256 × 16-bit organization - meaning it stores 256 words of 16 bits each, totaling 4 Kbit. Unlike 'C' variants, it lacks an ORG pin and does not support runtime switching between 8-bit and 16-bit modes. This configuration is optimized for systems using 16-bit data paths or requiring compact storage of dual-byte parameters.
Does the 93C66B-I/ST require an external ORG pin connection?
No, the 93C66B-I/ST does not require or support an ORG pin. As a 'B' variant, it is hardwired for 16-bit operation. Pins 6 and 7 are marked NC (No Connection) in the SOIC-8 package and must remain unconnected. This eliminates external configuration logic and simplifies PCB layout compared to 'C' versions.
What is the minimum VCC required for ERAL and WRAL operations on the 93C66B-I/ST?
The 93C66B-I/ST requires VCC ≥ 4.5 V to execute ERAL (Erase All) and WRAL (Write All) commands reliably. This is specified in the datasheet's functional description and AC characteristics tables. Attempting these operations below 4.5 V may result in incomplete erasure or write failure, as the internal charge pump cannot generate sufficient programming voltage.
How does the 93C66B-I/ST indicate Ready/Busy status during a write cycle?
The 93C66B-I/ST asserts Ready/Busy status on the DO pin: DO = low indicates active erase/write in progress; DO = high signals completion and readiness for the next command. To sample this, CS must be brought high for ≥250 ns after initiating the operation - holding CS low keeps DO in High-Z state and hides status.
Is the 93C66B-I/ST pin-compatible with other devices in the 93XX66 family?
The 93C66B-I/ST shares the same 8-lead SOIC (ST) package and pinout with 93AA66B-I/ST, 93LC66B-I/ST, and 93C66A-I/ST - all have identical CS/CLK/DI/DO/VSS/VCC assignments. However, voltage ranges and feature sets differ: 93C66B-I/ST is 4.5–5.5 V only, while 93LC66B-I/ST operates down to 2.5 V and includes different POR thresholds and timing specs.
93C66B-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:
- 256 x 16
- 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-TSSOP
93C66B-I/ST FAQ
1.How can I place an order for 93C66B-I/ST through Aetrix?
Please submit a Request for Quotation (RFQ) for 93C66B-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 93C66B-I/ST reliable?
The price and inventory of 93C66B-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 93C66B-I/ST is usually 5 days.
3.What payment methods are accepted for 93C66B-I/ST?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for 93C66B-I/ST transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for 93C66B-I/ST?
93C66B-I/ST orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your 93C66B-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 93C66B-I/ST?
For technical support, including 93C66B-I/ST datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your 93C66B-I/ST requirements.
6.How does Aetrix verify that 93C66B-I/ST is sourced from the original manufacturer or authorized distributors?
All 93C66B-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 93C66B-I/ST meets industry standards.
7.What is the process for return or replacement of 93C66B-I/ST?
All 93C66B-I/ST units undergo pre-shipment inspection (PSI). If there is an issue with 93C66B-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 93C66B-I/ST part is unused and in its original packaging.
Return procedure for 93C66B-I/ST:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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