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Microchip Technology 93LC66A/ST
- Part No.:
- 93LC66A/ST
- Manufacturer:
- Microchip Technology
- Category:
- Memory
- Package:
- 8-TSSOP (0.173", 4.40mm Width)
- Datasheet:
-
93LC66A/ST.pdf
- Description:
- IC EEPROM 4KBIT MICROWIRE 8TSSOP
- Quantity:
- Payment:
- Shipping:
Inventory:4,264
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Product details
Overview
93LC66A/ST from Microchip Technology Inc. is a 4 Kbit (512 × 8-bit) low-voltage serial EEPROM with Microwire-compatible 3-wire interface, 2.5–5.5 V supply range, and industrial/automotive temperature support (−40°C to +125°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 firmware parameter backup.
For engineers reviewing the 93LC66A/ST datasheet, 93LC66A/ST pinout, 93LC66A/ST application, or 93LC66A/ST equivalent, key selection criteria include its dedicated 8-bit organization (no ORG pin), TSSOP-8 package compatibility, 6 ms program cycle time, and support for sequential read and WRAL/ERAL commands in space-constrained industrial controllers.
Technical Context
The 93LC66A/ST implements a synchronous serial Microwire protocol with CS, CLK, and DI/DO lines - no ORG pin required, fixed x8 memory mapping. Communication begins with a Start bit (CS high + DI high on CLK rising edge), followed by opcode, address, and data bits clocked on CLK rising edges.
It uses internal auto-erase-before-write logic and supports full-array operations: ERAL (6 ms, VCC ≥ 4.5 V) and WRAL (15 ms, VCC ≥ 4.5 V). Ready/Busy status is polled via DO pin after CS reassertion with ≥250 ns low time (TCSL), enabling non-blocking host control.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Memory size | 4 Kbit (512 × 8-bit), fixed x8 organization - no external ORG pin needed; simplifies PCB layout and firmware addressing. |
| VCC range | 2.5 V to 5.5 V - supports direct connection to 3.3 V or 5 V rails without level-shifting in mixed-voltage systems. |
| Endurance | 1,000,000 erase/write cycles - ensures reliable field updates over product lifetime in telemetry or logging applications. |
| Data retention | 200 years at 25°C - guarantees long-term calibration data integrity in unpowered storage or infrequently powered devices. |
| Program cycle time | 6 ms typical - enables fast parameter updates during boot or maintenance mode without blocking real-time operation. |
| Interface | Microwire-compatible 3-wire serial (CS/CLK/DI/DO) - minimal GPIO usage; compatible with legacy MCU peripherals lacking SPI hardware. |
| Temp range | −40°C to +125°C (Automotive E-grade) - qualified for under-hood, motor control, and industrial drive environments. |
Pinout & Package
93LC66A/ST is supplied in an 8-lead TSSOP package (ST suffix), with 3.0 mm × 4.4 mm body, 0.65 mm pitch, and exposed pad optional per Microchip spec. Pin 1 marked by laser dot; pin 1 ID corner matches standard JEDEC orientation.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| CS (Pin 1) | Chip Select | Active-high enable: must be held ≥250 ns low between instructions; falling edge initiates self-timed write/erase on 93LC devices. |
| CLK (Pin 2) | Serial Clock | Synchronizes all data transfers; rising edge clocks in opcode/address/data; stoppable mid-sequence for host flexibility. |
| DI (Pin 3) | Data Input | Receives Start bit, opcodes, addresses, and write data; shares no internal conflict with DO in standard operation. |
| DO (Pin 4) | Data Output / Status | Outputs read data or Ready/Busy (low = busy); enters High-Z when CS low or during non-read states. |
| VSS (Pin 5) | Ground | Reference return path for all I/O and core logic; requires low-impedance connection to minimize noise coupling. |
| NC (Pin 6) | No Connect | Internally unconnected; must be left floating or tied to VSS per layout best practice - no functional role. |
| VCC (Pin 7) | Power Supply | 2.5–5.5 V input; includes internal POR circuitry that inhibits writes below ~1.5 V to prevent corruption during brownout. |
| NC (Pin 8) | No Connect | Unused terminal; electrically isolated - no routing or termination required. |
Key Features
| Feature | Design Value |
|---|---|
| Self-timed erase/write | Eliminates external timing control - host only monitors DO pin for completion, reducing firmware complexity and CPU overhead. |
| Automatic ERAL before WRAL | Guarantees clean array state prior to bulk write, preventing partial-data corruption without requiring separate erase command sequence. |
| Power-on/off data protection | Hardware-level write inhibition below VCC threshold (~1.5 V) prevents inadvertent writes during power ramp-up/down or supply glitches. |
| Ready/Busy status signaling | DO pin doubles as status indicator - enables polling-based host synchronization without dedicated interrupt lines or timers. |
| Sequential read function | Allows continuous address incrementing while CS remains high, accelerating bulk read of configuration blocks or lookup tables. |
Applications
| Industrial Sensor Calibration Storage | Automotive Body Control Module (BCM) |
|---|---|
Use Scenario: Storing factory-calibrated offset/gain coefficients for temperature, pressure, and current sensors in programmable logic controllers. IC Role / Device Role / Timing Role: Nonvolatile parameter register accessed during power-up initialization and field recalibration routines. Use Value: 200-year data retention and 1M endurance ensure calibration validity across decades of operation without battery backup. | Use Scenario: Retaining user-configurable settings (window lift position, mirror angle, lighting profiles) in automotive BCMs operating at −40°C to +125°C. IC Role / Device Role / Timing Role: Dedicated configuration EEPROM interfaced via MCU's Microwire peripheral during ignition-on and sleep-mode wake events. Use Value: E-grade qualification and 2.5–5.5 V operation allow direct integration into 12 V automotive supply networks with minimal regulation. |
| Medical Infusion Pump Parameter Backup | Smart Energy Meter Firmware Settings |
Use Scenario: Preserving drug library definitions, dose limits, and alarm thresholds in Class II medical devices subject to IEC 62304 requirements. IC Role / Device Role / Timing Role: Safety-critical configuration store accessed only during validated firmware update or device commissioning sequences. Use Value: Hardware write-protection (EWDS/EWEN) and ERAL/WRAL atomicity prevent accidental corruption during power loss or reset events. | Use Scenario: Holding tariff schedules, metering constants, and communication credentials in ANSI C12.22-compliant smart meters deployed in utility substations. IC Role / Device Role / Timing Role: Secure, tamper-resistant storage element updated remotely via PLC or RF mesh network during firmware upgrades. Use Value: Pb-free RoHS compliance and 125°C rating support conformal coating and long-life outdoor deployment in harsh environmental enclosures. |
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 - requires different address/data framing in firmware. | Used where wider bus width reduces instruction count for bulk data; not drop-in compatible due to x16 addressing. | Select only if system firmware already supports 16-bit word access and memory map alignment matches. |
| AT25040B-SSHL-T | SPI interface (4-wire), 4 Kbit (512 × 8), 1.8–5.5 V, 20 MHz max clock - higher speed but incompatible protocol stack. | Preferred in new designs using SPI peripherals; requires driver rewrite and layout changes for CS/CLK/MOSI/MISO routing. | Choose for faster throughput or SPI-standardized platforms; avoid for Microwire legacy migration without firmware investment. |
Compared with 93LC66B/ST, the 93LC66A/ST offers simpler 8-bit addressing and identical packaging - ideal for cost-sensitive, firmware-constrained upgrades. Versus AT25040B-SSHL-T, it trades speed and interface ubiquity for proven Microwire compatibility and lower gate-count MCU resource usage.
Availability
93LC66A/ST is available at Aetrix Electronics and suitable for industrial sensor calibration storage, automotive body control modules, and medical infusion pump parameter backup requiring stable component supply across extended product lifecycles.
Supply support for 93LC66A/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 microcontroller, analog, and Flash-IP solutions, headquartered in Chandler, Arizona, with global design and manufacturing operations.
The 93LC66A/ST belongs to Microchip's legacy 93XX serial EEPROM family, designed specifically for low-pin-count, low-power, nonvolatile memory applications in space- and cost-constrained embedded systems.
FAQ
What is the memory organization of the 93LC66A/ST?
The 93LC66A/ST has a fixed 512 × 8-bit (4 Kbit) organization with no ORG pin - unlike 'C' variants, it does not support x16 mode. This eliminates external configuration logic and simplifies firmware development for byte-oriented data structures. The 93LC66A/ST delivers deterministic 8-bit addressing and data transfer without runtime mode switching.
Does the 93LC66A/ST require an external ORG pin connection?
No, the 93LC66A/ST does not require or support an ORG pin - it is internally hardwired for 8-bit operation. Pins 6 and 8 are NC (No Connect) and must remain unconnected. This distinguishes it from 93LC66C/ST, which uses ORG to select x8/x16 modes. The 93LC66A/ST simplifies PCB layout and removes dependency on external pull-up/pull-down resistors.
What is the maximum clock frequency supported by the 93LC66A/ST?
The 93LC66A/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 (though 93LC66A minimum VCC is 2.5 V). These AC limits ensure reliable setup/hold timing across voltage and temperature ranges. Exceeding them risks data corruption during opcode or address capture.
How does the Ready/Busy status work on the 93LC66A/ST?
The 93LC66A/ST signals Ready/Busy status on the DO pin: DO = low indicates active erase/write, DO = high means operation complete. To poll, host must assert CS high after ≥250 ns low time (TCSL); DO enters High-Z if CS stays low. Issuing a Start bit then lowering CS clears prior status. This enables efficient non-blocking host control without dedicated status lines.
Is the 93LC66A/ST RoHS compliant and lead-free?
Yes, the 93LC66A/ST is Pb-free and RoHS compliant per Microchip DS21795E documentation. It uses Matte Tin (Sn) finish on all leads and conforms to JEDEC standards for lead-free packaging. The TSSOP-8 package (ST suffix) carries appropriate marking and is suitable for lead-free reflow processes with peak temperatures up to 260°C.
93LC66A/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:
- 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
93LC66A/ST FAQ
1.How can I place an order for 93LC66A/ST through Aetrix?
Please submit a Request for Quotation (RFQ) for 93LC66A/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 93LC66A/ST reliable?
The price and inventory of 93LC66A/ST are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for 93LC66A/ST is usually 5 days.
3.What payment methods are accepted for 93LC66A/ST?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for 93LC66A/ST transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for 93LC66A/ST?
93LC66A/ST orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your 93LC66A/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 93LC66A/ST?
For technical support, including 93LC66A/ST datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your 93LC66A/ST requirements.
6.How does Aetrix verify that 93LC66A/ST is sourced from the original manufacturer or authorized distributors?
All 93LC66A/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 93LC66A/ST meets industry standards.
7.What is the process for return or replacement of 93LC66A/ST?
All 93LC66A/ST units undergo pre-shipment inspection (PSI). If there is an issue with 93LC66A/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 93LC66A/ST part is unused and in its original packaging.
Return procedure for 93LC66A/ST:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
93LC66A/ST Tags
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AT24C02C-XHM-T
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AT21CS01-STUM10-T
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M24C02-FMC6TG
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AT24CS02-SSHM-T
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93LC46BT-I/OT
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24AA02UIDT-I/OT
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AT24C08C-STUM-T
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