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Microchip Technology 93LC66AT-E/ST
- Part No.:
- 93LC66AT-E/ST
- Manufacturer:
- Microchip Technology
- Category:
- Memory
- Package:
- 8-TSSOP (0.173", 4.40mm Width)
- Datasheet:
-
93LC66AT-E/ST.pdf
- Description:
- IC EEPROM 4KBIT MICROWIRE 8TSSOP
- Quantity:
- Payment:
- Shipping:
Inventory:3,393
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Product details
Overview
93LC66AT-E/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 automotive-grade temperature range (–40°C to +125°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 engine control units for calibration storage.
For engineers reviewing the 93LC66AT-E/ST datasheet, 93LC66AT-E/ST pinout, 93LC66AT-E/ST application, or 93LC66AT-E/ST equivalent, key selection criteria include VCC range (2.5–5.5 V), automotive qualification (E-temp), TSSOP-8 package, 8-bit x512 organization, and Ready/Busy status via DO pin during programming.
Technical Context
The 93LC66AT-E/ST implements a synchronous serial Microwire protocol with start-bit detection, opcode-driven instruction set (READ, WRITE, ERASE, ERAL, WRAL, EWEN/EWDS), and dual-mode memory access controlled by the ORG pin - though ORG is NC on this 'A' variant, fixing 8-bit operation. Internal logic enforces power-on write protection and auto-erase-before-write behavior.
It uses CMOS technology optimized for low standby current (≤5 µA at I-temp, ≤1 µA at E-temp) and supports sequential read, high-Z DO output during non-read states, and status polling via DO pin after minimum TCSL (250 ns). Clock frequency scales with VCC: up to 3 MHz at 4.5–5.5 V, 2 MHz at 2.5–4.5 V.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Memory size | 4 Kbit (512 × 8-bit organization) |
| VCC range | 2.5 V to 5.5 V - supports wide-input industrial and automotive power rails |
| Temperature grade | Automotive (E): –40°C to +125°C - qualified for under-hood ECUs and ADAS modules |
| Endurance | 1,000,000 erase/write cycles - enables frequent firmware parameter updates in field-deployed systems |
| Data retention | >200 years at +85°C - ensures long-term calibration data integrity without refresh |
| Interface | Microwire-compatible 3-wire serial (CS, CLK, DI/DO) - minimal GPIO usage on microcontrollers |
| Write cycle time | 6 ms typical (TWC) - deterministic timing for real-time system scheduling |
Pinout & Package
93LC66AT-E/ST is supplied in an 8-lead TSSOP package (ST suffix), with lead pitch 0.65 mm, body dimensions 4.4 mm × 3.0 mm × 1.2 mm, and Pb-free Matte Tin finish.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 CS | Chip Select | Active-high enable; must be held low ≥250 ns between instructions; initiates self-timed write on falling edge |
| 2 CLK | Serial Clock | Synchronizes all data transfers; rising edge clocks in opcodes, addresses, and data; stoppable mid-sequence |
| 3 DI | Data Input | Accepts start bit, instruction opcodes, address bits, and write data; shares bidirectional bus with DO in some layouts |
| 4 DO | Data Output / Status | Outputs read data on rising CLK edge; indicates Ready/Busy during erase/write (low = busy, high = ready) |
| 5 VSS | Ground | Reference for all digital and analog circuitry; must be low-impedance connection |
| 6 NC | No internal connection | Not bonded; must be left floating or tied to VSS per layout best practice |
| 7 ORG | Memory configuration | No internal connection on 'A' devices - fixed 8-bit mode; pin is NC and unused |
| 8 VCC | Power supply | Supplies core logic and EEPROM array; includes internal POR circuit triggered at ~2.5 V |
Key Features
| Feature | Design Value |
|---|---|
| Self-timed erase/write | Eliminates external timing control; 6 ms typical cycle completes autonomously after CS fall |
| Automatic ERAL before WRAL | Guarantees full-array erase prior to bulk write - prevents partial-data corruption during firmware update |
| Power-on/off data protection | Hardware-level inhibition below VCC threshold (~2.5 V) - blocks accidental writes during brown-out or startup |
| Ready/Busy status on DO | Enables non-blocking polling instead of fixed delays - improves system responsiveness and reduces CPU overhead |
| Industry-standard 3-wire interface | Reduces MCU pin count vs SPI; compatible with legacy Microwire controllers and widely supported drivers |
Applications
| Engine Control Unit (ECU) | Advanced Driver Assistance Systems (ADAS) |
|---|---|
Use Scenario: Storing adaptive fuel trim values, misfire counters, and diagnostic trouble codes (DTCs) that persist across ignition cycles. IC Role / Device Role / Timing Role: Nonvolatile configuration and runtime parameter storage with guaranteed data integrity during vehicle cranking and battery transients. Use Value: Automotive temperature rating and 1M-cycle endurance support 15+ year vehicle lifetimes with daily reprogramming. | Use Scenario: Holding camera calibration offsets, radar sensor compensation tables, and lane-departure warning thresholds. IC Role / Device Role / Timing Role: Secure, low-power memory for safety-critical calibration data requiring >200-year retention at elevated ambient temperatures. Use Value: VCC brown-out protection and automatic EWDS on power-up prevent corruption during voltage sags in ADAS domain controllers. |
| Industrial Programmable Logic Controller (PLC) | Medical Infusion Pump |
Use Scenario: Retaining user-defined I/O mapping, PID tuning parameters, and event logs in factory automation hardware. IC Role / Device Role / Timing Role: Serial EEPROM interfaced to ARM Cortex-M MCU via GPIO-banged Microwire for cost-sensitive embedded control. Use Value: TSSOP-8 package enables compact PCB layout; 2.5 V min VCC allows direct connection to 3.3 V rails without level-shifting. | Use Scenario: Storing drug library profiles, dosage history, and regulatory audit logs compliant with IEC 62304. IC Role / Device Role / Timing Role: Certified nonvolatile memory for Class II medical device firmware configuration and traceability records. Use Value: Pb-free RoHS compliance and AEC-Q100 alignment (via E-temp qualification) support global medical regulatory submissions. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar serial EEPROM applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| 93LC66BT-E/ST | 16-bit x256 organization; same VCC, temp, package; ORG pin NC but internally fixed to 16-bit mode | Requires 16-bit MCU data path; incompatible with 8-bit software drivers | Select only when system architecture mandates 16-bit word access and memory map alignment |
| AT25DF041A-SH-B | SPI interface (4-wire), 4 Mbit density, 2.7–3.6 V VCC, industrial temp only (–40°C to +85°C) | Lacks automotive qualification and Microwire compatibility; higher density but no ERAL/WRAL atomicity | Use when migrating to SPI-based platforms or requiring larger capacity; not drop-in for 93LC66AT-E/ST |
Compared with 93LC66BT-E/ST and AT25DF041A-SH-B, the 93LC66AT-E/ST uniquely delivers automotive-grade 8-bit Microwire EEPROM in TSSOP-8 with guaranteed ERAL-before-WRAL behavior and 2.5 V operation - critical for legacy ECU designs and cost-constrained safety systems.
Availability
93LC66AT-E/ST is available at Aetrix Electronics and suitable for engine control units, ADAS modules, industrial PLCs, and medical infusion pumps requiring stable component supply across extended product lifecycles.
Supply support for 93LC66AT-E/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, FPGA, and memory solutions, headquartered in Chandler, Arizona, with global design and manufacturing operations.
The 93LC66A/B/C series was designed specifically for cost-sensitive, low-power, nonvolatile memory applications in automotive, industrial, and consumer systems requiring Microwire compatibility and robust data retention.
FAQ
What is the memory organization of the 93LC66AT-E/ST?
The 93LC66AT-E/ST is a fixed 512 × 8-bit (4 Kbit) organization device. As an 'A' variant, it does not use the ORG pin - the memory is permanently configured for 8-bit word access, eliminating external configuration logic and simplifying firmware driver implementation.
Does the 93LC66AT-E/ST support automatic erase before write?
Yes, the 93LC66AT-E/ST performs automatic erase before each write operation. This self-timed feature ensures data integrity without requiring separate ERASE commands, and the entire process completes within the specified 6 ms TWC (program cycle time) after CS falls.
What is the function of the ORG pin on the 93LC66AT-E/ST?
On the 93LC66AT-E/ST, the ORG pin is marked as NC (No internal connection) in the datasheet and pin function table. It is not bonded and must be left unconnected or tied to VSS per layout guidelines - the device operates exclusively in 8-bit mode as defined by its 'A' suffix.
How is Ready/Busy status indicated on the 93LC66AT-E/ST?
The 93LC66AT-E/ST outputs Ready/Busy status on the DO pin: logic low indicates ongoing erase or write operation, while logic high confirms completion. Status is valid only after CS is brought high for ≥250 ns (TCSL) following instruction initiation - enabling efficient polling without fixed delays.
Is the 93LC66AT-E/ST qualified for automotive applications?
Yes, the 93LC66AT-E/ST carries the 'E' temperature grade suffix, certifying operation from –40°C to +125°C and compliance with automotive reliability requirements. Its packaging (TSSOP-8, ST suffix), Pb-free finish, and built-in power brown-out protection align with AEC-Q100 stress test expectations for ECU and ADAS subsystems.
93LC66AT-E/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:
- -40°C ~ 125°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 8-TSSOP
93LC66AT-E/ST FAQ
1.How can I place an order for 93LC66AT-E/ST through Aetrix?
Please submit a Request for Quotation (RFQ) for 93LC66AT-E/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-E/ST reliable?
The price and inventory of 93LC66AT-E/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-E/ST is usually 5 days.
3.What payment methods are accepted for 93LC66AT-E/ST?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for 93LC66AT-E/ST transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for 93LC66AT-E/ST?
93LC66AT-E/ST orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your 93LC66AT-E/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-E/ST?
For technical support, including 93LC66AT-E/ST datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your 93LC66AT-E/ST requirements.
6.How does Aetrix verify that 93LC66AT-E/ST is sourced from the original manufacturer or authorized distributors?
All 93LC66AT-E/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-E/ST meets industry standards.
7.What is the process for return or replacement of 93LC66AT-E/ST?
All 93LC66AT-E/ST units undergo pre-shipment inspection (PSI). If there is an issue with 93LC66AT-E/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-E/ST part is unused and in its original packaging.
Return procedure for 93LC66AT-E/ST:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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