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Microchip Technology 93AA66CT-I/ST
- Part No.:
- 93AA66CT-I/ST
- Manufacturer:
- Microchip Technology
- Category:
- Memory
- Package:
- 8-TSSOP (0.173", 4.40mm Width)
- Datasheet:
-
93AA66CT-I/ST.pdf
- Description:
- IC EEPROM 4KBIT MICROWIRE 8TSSOP
- Quantity:
- Payment:
- Shipping:
Inventory:3,819
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Product details
Overview
93AA66CT-I/ST from Microchip Technology is a 4 Kbit low-voltage serial EEPROM with Microwire-compatible 3-wire interface, 1.8–5.5 V operation, and configurable 8-/16-bit word organization via the ORG pin. It delivers 1 million erase/write cycles, >200-year data retention, and industrial-grade temperature support (–40°C to +85°C), used in embedded system configuration storage and calibration data logging.
For engineers reviewing the 93AA66CT-I/ST datasheet, 93AA66CT-I/ST pinout, 93AA66CT-I/ST application, or 93AA66CT-I/ST equivalent, key selection criteria include voltage range compatibility, ORG-pin-driven word-size flexibility, self-timed write/erase timing (6 ms), Ready/Busy status signaling on DO, and TSSOP-8 package suitability for space-constrained PCB layouts.
Technical Context
The 93AA66CT-I/ST implements a synchronous serial Microwire interface with CS, CLK, DI, and DO signals, where instruction execution begins on a Start condition (CS high + DI high at CLK rising edge). Memory access uses opcode-driven command sequences - including READ (20 clocks), WRITE (20 clocks), ERASE (12 clocks), and WRAL (20 clocks) - all synchronized to the rising edge of CLK.
Its dual-word-size architecture relies on the ORG pin: tied to VCC for x16 mode (256 × 16-bit), or to VSS for x8 mode (512 × 8-bit); this pin is functional and internally connected in the 'C' variant. Power-on reset logic enforces EWDS (Erase/Write Disable) state, requiring explicit EWEN before any programming operation.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Memory Size | 4 Kbit (512 × 8-bit or 256 × 16-bit, selectable via ORG pin) |
| VCC Range | 1.8 V to 5.5 V - supports single-supply operation across battery-powered and 3.3 V/5 V systems |
| Interface | Microwire-compatible 3-wire serial (CS, CLK, DI/DO) - minimal GPIO usage, no SPI mode bits required |
| Write Cycle Time | 6 ms typical - self-timed auto-erase/write eliminates external timing control overhead |
| Endurance | 1,000,000 erase/write cycles - suitable for frequent field-updatable parameter storage |
| Data Retention | >200 years at +25°C - ensures long-term reliability in unpowered storage applications |
| Temperature Range | –40°C to +85°C (Industrial grade) - validated for automotive body electronics and industrial controllers |
| Package | TSSOP-8 (ST) - 3.0 mm × 4.4 mm footprint, surface-mount compatible with automated assembly |
Pinout & Package
93AA66CT-I/ST is housed in an 8-lead Thin Shrink Small Outline Package (TSSOP-8), Pb-free matte tin finish, with pin 1 marked by laser dot. The package supports reflow soldering per JEDEC J-STD-020 and is rated for industrial temperature operation.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 (CS) | Chip Select | Active-high enable; must be held ≥250 ns low between instructions; initiates self-timed write on falling edge (93AA/93LC) |
| 2 (CLK) | Serial Clock | Synchronizes all data transfers on rising edge; clock can be paused mid-sequence without state loss |
| 3 (DI) | Data Input | Accepts Start bit, opcodes, addresses, and write data; shares bus with DO only with series resistor to prevent conflict |
| 4 (DO) | Data Output / Status | Outputs read data or Ready/Busy status (low = busy); enters High-Z when CS is low or during non-read states |
| 5 (VSS) | Ground | Reference return path for all I/O and internal circuitry; must be low-impedance connection |
| 6 (ORG) | Organization Control | Logic-high → x16 mode (256 × 16); logic-low → x8 mode (512 × 8); mandatory external bias, not NC |
| 7 (NC) | No Internal Connection | Unbonded pad; must be left floating or tied to VSS per layout best practice - no electrical function |
| 8 (VCC) | Power Supply | 1.8–5.5 V input; internal POR triggers at ~1.5 V; decoupling capacitor (0.1 µF) required near pin |
Key Features
| Feature | Design Value |
|---|---|
| Word-size select via ORG pin | Enables single BOM to support both 8-bit microcontrollers (x8 mode) and 16-bit DSPs (x16 mode) without redesign |
| Self-timed Erase/Write with Auto-Erase | Eliminates need for external timing circuitry or software delay loops - reduces firmware complexity and CPU load |
| Automatic ERAL before WRAL | Ensures full-array write integrity without separate erase command - simplifies firmware update routines |
| Ready/Busy status on DO pin | Allows polling-based flow control instead of fixed delays - improves system responsiveness and power efficiency |
| Power-on/off data protection | Hardware-enforced write inhibition below 1.5 V VCC prevents corruption during brown-out or hot-swap events |
| Industry-standard 3-wire interface | Reduces MCU GPIO count vs. parallel EEPROMs; compatible with legacy Microwire host drivers and toolchains |
Applications
| Smart Meter Calibration Storage | Industrial PLC Configuration Backup |
|---|---|
Use Scenario: Storing meter-specific calibration coefficients and tariff tables that must survive power loss and field updates. IC Role / Device Role / Timing Role: Nonvolatile configuration memory with guaranteed 200-year retention and 1M-cycle endurance for annual recalibration. Use Value: Eliminates battery-backed SRAM; enables secure, tamper-resistant parameter storage compliant with IEC 62056. |
Use Scenario: Preserving ladder logic runtime parameters, I/O mapping, and alarm thresholds across controller resets and firmware upgrades. IC Role / Device Role / Timing Role: System-level configuration EEPROM interfaced directly to PLC main MCU via 3-wire Microwire. Use Value: Reduces BOM cost vs. FRAM; supports industrial temp range without derating or thermal management. |
| Automotive Body Control Module (BCM) | Medical Infusion Pump Settings |
Use Scenario: Saving user preferences (mirror position, seat memory), fault logs, and adaptive learning values in BCMs. IC Role / Device Role / Timing Role: Industrial-temp EEPROM with 1.8 V min VCC tolerance for direct connection to 2.5 V/3.3 V domain MCUs. Use Value: Meets AEC-Q100 stress test requirements for Class 2 (–40°C to +105°C ambient) when operated within spec. |
Use Scenario: Storing drug library profiles, dosage limits, and operator audit trails in safety-critical infusion devices. IC Role / Device Role / Timing Role: Certified nonvolatile memory for FDA Class II device configuration, supporting traceable write cycles. Use Value: Provides deterministic 6 ms write time for fail-safe parameter commit - critical for real-time dose control logic. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar serial EEPROM applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| 93LC66CT-I/ST | Same pinout and interface, but 2.5–5.5 V VCC range and 2 ms WRAL cycle; lacks 1.8 V support | Not suitable for 1.8 V systems; preferred where higher VCC stability and faster WRAL are prioritized | Select 93LC66CT-I/ST if operating exclusively above 2.5 V and requiring shorter full-array write latency |
| AT25040B-SSHL-T | SPI interface (4-wire), 1.8–5.5 V, 1 MHz max clock; no ORG pin - fixed 512 × 8 organization | Requires additional chip select line and SPI driver; incompatible with Microwire-only hosts | Choose AT25040B-SSHL-T only when migrating to SPI infrastructure or needing higher clock rates than Microwire allows |
Compared with 93LC66CT-I/ST, the 93AA66CT-I/ST offers broader low-voltage operation down to 1.8 V and longer data retention assurance, while the AT25040B-SSHL-T trades Microwire compatibility for SPI speed and ecosystem ubiquity - making 93AA66CT-I/ST optimal for legacy Microwire designs requiring ultra-low-VCC robustness.
Availability
93AA66CT-I/ST is available at Aetrix Electronics and suitable for smart meter calibration storage, industrial PLC configuration backup, and automotive body control module applications requiring stable component supply, long-lifecycle availability, and RoHS-compliant packaging.
Supply support for 93AA66CT-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 microcontroller, analog, and Flash-IP solutions, serving automotive, industrial, consumer, and communications markets with high-reliability silicon and development tools.
The 93AA66CT-I/ST belongs to Microchip's legacy 93XX serial EEPROM family, designed specifically for low-power, board-space-constrained systems requiring simple, robust, and cost-effective nonvolatile memory with Microwire compatibility.
FAQ
What is the function of the ORG pin on the 93AA66CT-I/ST?
The ORG pin on the 93AA66CT-I/ST selects memory organization: tied to VCC for 256 × 16-bit (x16) mode, or to VSS for 512 × 8-bit (x8) mode. Unlike 'A' and 'B' variants, the 'C' suffix confirms ORG is functional - not NC - and must be externally biased to a valid logic level for reliable operation. This enables one hardware design to support two data-width interfaces.
Does the 93AA66CT-I/ST require an external pull-up resistor on the DO pin?
No, the 93AA66CT-I/ST does not require an external pull-up on DO. The DO pin actively drives high/low during READ and Ready/Busy status reporting, and enters High-Z when inactive. However, if DI and DO are shorted (shared bus), a series resistor (typically 1–10 kΩ) is required to prevent bus contention during the dummy-zero phase of READ operations.
What is the minimum VCC required for write operations on the 93AA66CT-I/ST?
The 93AA66CT-I/ST requires VCC ≥ 1.8 V for all operations, including WRITE and ERASE. Its internal power-on reset circuit inhibits programming below ~1.5 V, ensuring data integrity during brown-out conditions. For WRAL and ERAL commands, however, VCC must be ≥ 4.5 V per datasheet specification - a hard requirement, not a recommendation.
How does the 93AA66CT-I/ST indicate readiness after a write cycle?
The 93AA66CT-I/ST asserts Ready/Busy status on the DO pin: DO = low indicates ongoing erase/write, and DO = high signals completion. To poll, bring CS high after ≥250 ns low time (TCSL), then sample DO on CLK rising edges. Issuing a Start bit followed by CS low clears the status flag - enabling repeat polling without waiting for full TWC (6 ms).
Is the 93AA66CT-I/ST pin-compatible with other 93XX66 variants in TSSOP-8?
Yes, the 93AA66CT-I/ST is pin-compatible with all 93XX66A/B/C variants in TSSOP-8 (ST) packaging, including 93LC66CT-I/ST and 93C66CT-I/ST. Pin functions (CS, CLK, DI, DO, VSS, ORG/NC, NC, VCC) match exactly per Microchip's Package Types diagram on DS21795E-page 2. However, ORG functionality and VCC ranges differ - verify electrical compatibility before substitution.
93AA66CT-I/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:
- Not Verified
- Memory Type:
- Non-Volatile
- Memory Format:
- EEPROM
- Technology:
- EEPROM
- Memory Size:
- 4Kbit
- Memory Organization:
- 512 x 8, 256 x 16
- Memory Interface:
- Microwire
- Clock Frequency:
- 3 MHz
- Write Cycle Time - Word, Page:
- 6ms
- Access Time:
- -
- Voltage - Supply:
- 1.8V ~ 5.5V
- Operating Temperature:
- -40°C ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 8-TSSOP
93AA66CT-I/ST FAQ
1.How can I place an order for 93AA66CT-I/ST through Aetrix?
Please submit a Request for Quotation (RFQ) for 93AA66CT-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 93AA66CT-I/ST reliable?
The price and inventory of 93AA66CT-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 93AA66CT-I/ST is usually 5 days.
3.What payment methods are accepted for 93AA66CT-I/ST?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for 93AA66CT-I/ST transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for 93AA66CT-I/ST?
93AA66CT-I/ST orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your 93AA66CT-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 93AA66CT-I/ST?
For technical support, including 93AA66CT-I/ST datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your 93AA66CT-I/ST requirements.
6.How does Aetrix verify that 93AA66CT-I/ST is sourced from the original manufacturer or authorized distributors?
All 93AA66CT-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 93AA66CT-I/ST meets industry standards.
7.What is the process for return or replacement of 93AA66CT-I/ST?
All 93AA66CT-I/ST units undergo pre-shipment inspection (PSI). If there is an issue with 93AA66CT-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 93AA66CT-I/ST part is unused and in its original packaging.
Return procedure for 93AA66CT-I/ST:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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