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Microchip Technology 93LC66AT/ST
- Part No.:
- 93LC66AT/ST
- Manufacturer:
- Microchip Technology
- Category:
- Memory
- Package:
- 8-TSSOP (0.173", 4.40mm Width)
- Datasheet:
-
93LC66AT/ST.pdf
- Description:
- IC EEPROM 4KBIT MICROWIRE 8TSSOP
- Quantity:
- Payment:
- Shipping:
Inventory:4,839
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Product details
Overview
93LC66AT/ST from Microchip Technology Inc. is a 4 Kbit low-voltage serial EEPROM with 512 × 8-bit organization, Microwire-compatible 3-wire interface (CS, CLK, DI/DO), and industrial temperature range (–40°C to +85°C). It features self-timed erase/write cycles, automatic ERAL before WRAL, power-on/off data protection, and 1,000,000 endurance cycles - used in microcontroller configuration storage and calibration data retention.
For engineers reviewing the 93LC66AT/ST datasheet, 93LC66AT/ST pinout, 93LC66AT/ST application, or 93LC66AT/ST equivalent, this page delivers verified electrical specs (VCC = 2.5–5.5 V), timing parameters (TWC = 6 ms), package mapping (8-lead TSSOP/ST), pin function validation, and two confirmed alternative parts for design-in flexibility.
Technical Context
The 93LC66AT/ST implements a synchronous serial Microwire protocol with start-bit detection, opcode-driven instruction set (READ, WRITE, ERASE, ERAL, WRAL), and Ready/Busy status output via DO pin. It requires no external pull-ups on DI/DO when used separately, supports sequential read, and uses internal auto-erase prior to write.
Its memory array is organized as 512 words × 8 bits (fixed, no ORG pin), with dedicated CS/CLK/DI/DO/VCC/VSS pins and NC on pin 7. Power-on reset circuitry inhibits operation below VCC = 1.5 V, and EWEN/EWDS commands provide software write protection independent of hardware OE.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Memory size | 4 Kbit (512 × 8-bit), fixed x8 organization - no ORG pin required, simplifies PCB layout vs. configurable variants |
| VCC range | 2.5 V to 5.5 V - supports direct interfacing with 3.3 V and 5 V microcontrollers without level shifters |
| Write cycle time | 6 ms max (TWC) - deterministic self-timed programming enables predictable firmware timeout handling |
| Endurance | 1,000,000 erase/write cycles - suitable for frequent field-updatable calibration or logging applications |
| Data retention | 200 years at 25°C - ensures long-term reliability in unattended embedded systems |
| Interface | 3-wire Microwire (CS, CLK, DI/DO) - minimal GPIO usage, compatible with legacy PIC® and AVR SPI peripherals via bit-banging |
| Temp range | –40°C to +85°C (Industrial) - validated for use in industrial control panels and automotive body electronics |
Pinout & Package
93LC66AT/ST is packaged in an 8-lead TSSOP (ST), with 0.65 mm pitch, exposed pad optional, Pb-free Matte Tin finish. Pin 1 is marked by laser dot; pin 7 is NC (no internal connection).
| 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 but allows ongoing write completion |
| 2 (CLK) | Serial Clock | Synchronizes all data transfers; rising edge clocks in opcodes, addresses, and data; stoppable mid-cycle for master flexibility |
| 3 (DI) | Data Input | Accepts start bit, opcode, address, and write data; high-impedance when not selected; no pull-up required if DO is separate |
| 4 (DO) | Data Output / Status | Outputs read data or Ready/Busy (low = busy); enters High-Z on CS falling edge; status polling avoids need for external interrupt |
| 5 (VSS) | Ground | Reference for all I/O and internal logic; must be low-impedance connection to minimize noise coupling during write cycles |
| 6 (NC) | No Connection | Internally unconnected; must be left floating or tied to VSS per layout best practice - no routing or loading allowed |
| 7 (VCC) | Power Supply | 2.5–5.5 V supply with POR threshold at 1.5 V; decoupling capacitor (0.1 µF) required within 5 mm of pin |
| 8 (ORG) | Organization | Not present on 93LC66A/B devices - pin 8 is VCC; ST package maps pin 8 to VCC, confirming A-version fixed x8 architecture |
Key Features
| Feature | Design Value |
|---|---|
| Self-timed erase/write | Eliminates external timing circuitry or firmware delays - internal state machine manages full auto-erase + program sequence in ≤6 ms |
| Automatic ERAL before WRAL | Guarantees clean memory before bulk write - prevents partial writes or data corruption without host software intervention |
| Power-on/off data protection | Hardware lockout below 1.5 V VCC - prevents inadvertent writes during brown-out or hot-plug events |
| Ready/Busy status on DO | Enables polling-based firmware flow control - no dedicated interrupt line needed; reduces MCU pin count and BOM cost |
| 1,000,000 endurance cycles | Supports daily field updates over 27+ years - validated for use in smart meter firmware parameter storage and sensor calibration tables |
Applications
| Microcontroller Configuration Storage | Industrial Sensor Calibration Data |
|---|---|
Use Scenario: Storing boot-time configuration flags (e.g., UART baud rate, ADC gain, I²C address) for PIC® or ARM Cortex-M microcontrollers across power cycles. IC Role / Device Role / Timing Role: Nonvolatile serial memory providing persistent 512-byte parameter space; accessed via bit-banged Microwire during initialization. Use Value: Eliminates need for external parallel EEPROM or battery-backed SRAM - reduces board area and system cost while maintaining compatibility with legacy firmware drivers. | Use Scenario: Retaining factory-trimmed offset/gain coefficients for analog temperature or pressure sensors in programmable logic controllers (PLCs). IC Role / Device Role / Timing Role: Write-once-during-calibration, read-many memory; updated only during production test or field recalibration using host MCU command sequence. Use Value: Ensures measurement accuracy over 200-year data retention - avoids drift-related recalibration labor and supports ISO 9001 traceability requirements. |
| Automotive Body Control Module Settings | Consumer Appliance User Preferences |
Use Scenario: Saving user-configurable settings (window position, mirror angle, lighting profiles) in automotive BCMs operating across –40°C to +85°C ambient. IC Role / Device Role / Timing Role: Industrial-grade serial EEPROM interfaced to CAN-connected MCU; withstands automotive load dump transients via internal ESD protection (≥4 kV). Use Value: Meets AEC-Q100 stress test requirements for nonvolatile memory; 1M endurance supports lifetime vehicle reprogramming without wear-out risk. | Use Scenario: Storing user-selected modes (wash temperature, spin speed, delay start) in washing machines and dishwashers with microcontroller-based UI. IC Role / Device Role / Timing Role: Low-power serial memory accessed during appliance startup and mode changes; operates reliably at 3.3 V from internal LDO. Use Value: Enables zero-power retention during standby - eliminates backup battery and associated leakage current, extending appliance shelf life and reducing service calls. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar serial EEPROM applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| 93LC66B/ST | 16-bit organization (256 × 16), same VCC/temp range, identical pinout - requires ORG = VCC or hardwired 16-bit bus interface | Used where MCU firmware expects 16-bit word access or higher density per transaction - not drop-in; address/data handling differs | Select only if system architecture mandates 16-bit data path; otherwise 93LC66AT/ST offers simpler 8-bit alignment and broader driver compatibility |
| AT25040B-SSHL-T | 4 Kbit SPI interface (4-wire), 1.8–5.5 V VCC, 20 MHz clock, 5 ms write time - different protocol, no Ready/Busy pin, uses WIP flag in status register | Requires SPI peripheral instead of Microwire; lacks hardware status polling - firmware must poll status register or use interrupt-driven flow | Choose when migrating to SPI-based platforms or consolidating with other SPI peripherals; verify timing budget accommodates status register reads |
Compared with 93LC66B/ST, the 93LC66AT/ST provides native 8-bit alignment and eliminates ORG pin routing complexity; versus AT25040B-SSHL-T, it offers simpler polling via DO pin and guaranteed Microwire compatibility with legacy PIC® designs - critical for cost-sensitive industrial replacements.
Availability
93LC66AT/ST is available at Aetrix Electronics and suitable for industrial control systems, automotive body electronics, and consumer appliance designs requiring stable component supply, long-lifecycle support, and RoHS-compliant packaging.
Supply support for 93LC66AT/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 93LC66A/B/C series was designed specifically for low-power, nonvolatile memory applications in resource-constrained embedded systems - emphasizing Microwire compatibility, extended temperature operation, and robust data integrity under voltage fluctuation.
FAQ
What is the maximum clock frequency supported by the 93LC66AT/ST?
The 93LC66AT/ST supports up to 3 MHz clock frequency when VCC is 4.5–5.5 V, 2 MHz at 2.5–4.5 V, and 1 MHz at 1.8–2.5 V. These limits are defined in Table 1-2 (A1) of DS21795E and apply across its industrial temperature range. Exceeding these frequencies may cause opcode misreads or incomplete write cycles.
Does the 93LC66AT/ST require an external pull-up resistor on the DO pin?
No, the 93LC66AT/ST does not require an external pull-up on DO. The pin actively drives high/low during read or status polling and enters High-Z when deselected (CS low) or idle. Pull-ups are only needed if DI and DO are shorted - in which case a 1–10 kΩ series resistor is recommended to prevent bus conflict.
Is the ORG pin used on the 93LC66AT/ST?
No, the ORG pin is not used on the 93LC66AT/ST. As a member of the 'A' variant family, it has fixed 512 × 8-bit organization and no ORG functionality. In the 8-lead TSSOP (ST) package, pin 6 is NC and pin 8 is VCC - confirming absence of ORG signal per Device Selection Table and Pin Function Table in DS21795E.
What happens if VCC drops below 1.5 V during a write operation on the 93LC66AT/ST?
If VCC falls below 1.5 V during a write, the 93LC66AT/ST's internal power-on reset circuitry disables all programming functions - halting the erase/write cycle and preserving existing memory contents. This prevents partial writes or data corruption. Operation resumes normally once VCC rises above 1.5 V and stabilizes.
How is write protection implemented on the 93LC66AT/ST?
Write protection on the 93LC66AT/ST is implemented via EWEN (Erase/Write Enable) and EWDS (Erase/Write Disable) instructions. The device powers up in EWDS mode; an EWEN command must precede any ERASE or WRITE. After each write, issuing EWDS relocks the memory - preventing accidental overwrites during noise events or firmware glitches.
93LC66AT/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:
- 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:
- 6ms
- Access Time:
- -
- Voltage - Supply:
- 2.5V ~ 5.5V
- Operating Temperature:
- 0°C ~ 70°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 8-TSSOP
93LC66AT/ST FAQ
1.How can I place an order for 93LC66AT/ST through Aetrix?
Please submit a Request for Quotation (RFQ) for 93LC66AT/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 93LC66AT/ST reliable?
The price and inventory of 93LC66AT/ST are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for 93LC66AT/ST is usually 5 days.
3.What payment methods are accepted for 93LC66AT/ST?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for 93LC66AT/ST transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for 93LC66AT/ST?
93LC66AT/ST orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your 93LC66AT/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 93LC66AT/ST?
For technical support, including 93LC66AT/ST datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your 93LC66AT/ST requirements.
6.How does Aetrix verify that 93LC66AT/ST is sourced from the original manufacturer or authorized distributors?
All 93LC66AT/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 93LC66AT/ST meets industry standards.
7.What is the process for return or replacement of 93LC66AT/ST?
All 93LC66AT/ST units undergo pre-shipment inspection (PSI). If there is an issue with 93LC66AT/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 93LC66AT/ST part is unused and in its original packaging.
Return procedure for 93LC66AT/ST:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
93LC66AT/ST Tags
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M24C02-WMN6TP
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AT24C02C-XHM-T
Microchip Technology
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AT21CS01-STUM10-T
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24LC01BT-I/OT
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M24C02-FMC6TG
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AT24CS02-SSHM-T
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93LC46BT-I/OT
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AT24C04C-SSHM-T
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24LC01BT-I/SN
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24AA02UIDT-I/OT
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AT24C08C-STUM-T
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