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Microchip Technology 93AA66A-I/ST
- Part No.:
- 93AA66A-I/ST
- Manufacturer:
- Microchip Technology
- Category:
- Memory
- Package:
- 8-TSSOP (0.173", 4.40mm Width)
- Datasheet:
-
93AA66A-I/ST.pdf
- Description:
- IC EEPROM 4KBIT MICROWIRE 8TSSOP
- Quantity:
- Payment:
- Shipping:
Inventory:940
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Product details
Overview
93AA66A-I/ST from Microchip Technology Inc. is a 4 Kbit (512 × 8-bit) low-voltage serial EEPROM with Microwire-compatible 3-wire interface, 1.8–5.5 V supply range, and industrial temperature rating (–40°C to +85°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 93AA66A-I/ST datasheet, 93AA66A-I/ST pinout, 93AA66A-I/ST application, or 93AA66A-I/ST equivalent, key selection criteria include its dedicated 8-bit organization (no ORG pin), TSSOP-8 package compatibility, 1 million erase/write endurance, >200-year data retention, and support for sequential read and WRAL/ERAL commands under 1.8 V operation.
Technical Context
This device implements a synchronous serial Microwire protocol with CS, CLK, DI, and DO signals - no ORG pin required, fixed 8-bit word width. Internal logic enforces power-on write protection and auto-erase-before-write behavior, eliminating external timing control for programming cycles.
It uses CMOS EEPROM cell technology with on-chip charge pump for 1.8 V operation, supports polling-based Ready/Busy status via DO during erase/write, and requires only 250 ns minimum CS low time between instructions. All operations are initiated by rising-edge clocked opcodes followed by address and data fields.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Memory size | 4 Kbit (512 × 8-bit); provides compact nonvolatile storage for boot parameters or calibration tables without external address decoding. |
| VCC range | 1.8–5.5 V; enables direct interfacing with 1.8 V, 2.5 V, 3.3 V, and 5 V microcontrollers without level shifters. |
| Interface | Microwire-compatible 3-wire serial (CS/CLK/DI/DO); minimal GPIO usage, no SPI mode bits or chip-select arbitration logic needed. |
| Endurance | 1,000,000 erase/write cycles; suitable for applications requiring frequent field updates like metering logs or adaptive tuning values. |
| Data retention | >200 years at +25°C; ensures long-term reliability in unpowered storage of critical configuration or security keys. |
| Write cycle time | 6 ms typical (TWC); deterministic self-timed programming eliminates need for software delay loops or interrupt-driven completion detection. |
| Operating temperature | –40°C to +85°C (Industrial grade); qualified for use in industrial controls, automotive body electronics, and outdoor IoT nodes. |
Pinout & Package
8-pin TSSOP package (ST suffix), 3.0 mm × 4.4 mm body, 0.65 mm pitch. Pin 1 marked by laser dot; exposed pad not present.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 (CS) | Chip Select | Active-high enable; must be held high ≥250 ns between instructions; falling edge initiates erase/write after last data bit. |
| 2 (CLK) | Serial Clock | Rising-edge synchronized I/O; supports variable clock frequency up to 3 MHz at 4.5–5.5 V; stop/resume allowed mid-transfer. |
| 3 (DI) | Data Input | Accepts start bit, opcode, address, and data; tied to DO only with series resistor to avoid bus conflict during dummy-zero read phase. |
| 4 (DO) | Data Output / Status | Outputs read data or Ready/Busy status (low = busy); enters High-Z when CS low or during standby; requires CS high ≥250 ns to sample status. |
| 5 (VSS) | Ground | Reference for all digital and analog circuitry; must be low-impedance connection to minimize noise coupling into DO timing. |
| 6 (NC) | No Connect | Internally unconnected; must be left floating or tied to VSS per layout best practice - no functional role in 93AA66A. |
| 7 (NC) | No Connect | Same as Pin 6; dual NC pins confirm absence of ORG functionality in 'A' version - no memory reconfiguration possible. |
| 8 (VCC) | Power Supply | Supplies internal charge pump and logic; voltage detect threshold at 1.5 V prevents writes during brown-out; decoupling capacitor mandatory. |
Key Features
| Feature | Design Value |
|---|---|
| Self-timed erase/write | Eliminates external timing control - host MCU proceeds immediately after CS fall; reduces firmware complexity and interrupt latency. |
| Automatic ERAL before WRAL | Guarantees full-array readiness prior to bulk write; prevents partial writes or data corruption if previous erase was interrupted. |
| Power-on/off data protection | Hardware-enforced write inhibit below 1.5 V VCC; protects memory contents during power ramp-up/down without software intervention. |
| Ready/Busy status on DO | Enables efficient polling instead of fixed delays - reduces average write latency and avoids overestimating worst-case timing. |
| Sequential read mode | Continuous data stream across addresses with single CS assertion; cuts transaction overhead by ~40% vs. individual byte reads. |
| Pb-free & RoHS compliant | Matte tin finish on all packages; meets global environmental compliance requirements for industrial and consumer end equipment. |
Applications
| Smart Energy Metering | Industrial PLC Configuration |
|---|---|
|
Use Scenario: Storing tariff schedules, pulse-count calibration factors, and tamper-event logs in electricity meters operating across wide temperature ranges. IC Role / Device Role / Timing Role: Nonvolatile configuration register holding metrology-critical constants updated infrequently but requiring guaranteed retention over 15+ years. Use Value: 1M endurance and >200-year data retention ensure field units maintain accuracy without replacement; 1.8 V operation supports ultra-low-power wake-up modes. |
Use Scenario: Retaining I/O mapping tables, PID loop coefficients, and alarm thresholds in programmable logic controllers deployed in factory automation cabinets. IC Role / Device Role / Timing Role: Dedicated parameter store accessed only during commissioning or maintenance - isolated from real-time control path. Use Value: Microwire interface minimizes pin count on legacy microcontrollers; industrial temp grade ensures stability inside heated enclosures. |
| Automotive Body Control Module | Medical Diagnostic Equipment |
|
Use Scenario: Saving seat/mirror position presets, lighting profiles, and error history in BCMs where ECU space and BOM cost are constrained. IC Role / Device Role / Timing Role: Secondary configuration memory co-located with main MCU; accessed during initialization or user input events. Use Value: TSSOP-8 footprint allows dense PCB layout; 512 × 8-bit organization matches common byte-aligned parameter structures. |
Use Scenario: Archiving calibration coefficients, sensor offset corrections, and regulatory audit trails in portable ultrasound or ECG devices. IC Role / Device Role / Timing Role: Secure, traceable nonvolatile storage for FDA-required device configuration records with write-protection integrity. Use Value: Hardware write-disable (EWDS default) prevents accidental overwrite during diagnostics; RoHS compliance satisfies medical supply chain mandates. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar serial EEPROM applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| 93LC66A-I/ST | Same 512 × 8-bit organization, but 2.5–5.5 V VCC range; lacks 1.8 V support. | Not suitable for 1.8 V systems; otherwise identical instruction set and timing. | Select 93AA66A-I/ST when 1.8 V operation or extended low-voltage margin is required. |
| AT25040B-SSHL-T | SPI interface (4-wire), 512 × 8-bit, 1.8–5.5 V, 20 MHz max clock; no Ready/Busy pin - relies on WIP flag polling. | Requires SPI-capable MCU; higher throughput but adds software overhead for status checking. | Choose AT25040B-SSHL-T only if existing design already uses SPI peripherals and needs faster random access. |
Compared with 93LC66A-I/ST, the 93AA66A-I/ST extends low-voltage operation to 1.8 V while retaining identical pinout and command structure; versus AT25040B-SSHL-T, it trades SPI speed for simpler 3-wire control and hardware-ready signaling - reducing firmware validation effort in resource-constrained designs.
Availability
93AA66A-I/ST is available at Aetrix Electronics and suitable for smart energy metering, industrial PLC configuration, and automotive body control modules requiring stable component supply, long-lifecycle support, and RoHS-compliant packaging.
Supply support for 93AA66A-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 industrial, automotive, and consumer markets with high-reliability silicon and development tools.
The 93AA66A-I/ST belongs to Microchip's legacy 93XX serial EEPROM product line, designed specifically for cost-sensitive, low-pin-count embedded systems needing robust nonvolatile storage with minimal external components.
FAQ
What is the memory organization of the 93AA66A-I/ST?
The 93AA66A-I/ST has a fixed 512 × 8-bit (4 Kbit) organization with no ORG pin - unlike 'C' variants, it does not support runtime switching between 8-bit and 16-bit modes. This simplifies hardware design by eliminating external ORG pull-up/pull-down requirements and guarantees consistent byte-aligned addressing for all firmware implementations targeting the 93AA66A-I/ST.
Does the 93AA66A-I/ST support 1.8 V operation?
Yes, the 93AA66A-I/ST operates across 1.8–5.5 V, making it compatible with modern ultra-low-power microcontrollers. Its internal charge pump enables full functionality including erase/write at 1.8 V, with verified AC timing down to that voltage - confirmed in Table 1-2 of DS21795E where FCLK min/max values are specified for 1.8 V ≤ VCC < 2.5 V conditions.
How is write protection implemented on the 93AA66A-I/ST?
The 93AA66A-I/ST powers up in Erase/Write Disable (EWDS) mode, blocking all programming until an explicit EWEN instruction is issued. After each write, best practice is to issue EWDS again - this hardware-enforced lock prevents accidental overwrites during power transients or firmware glitches. Unlike software-only flags, this protection remains active even if the host MCU resets unexpectedly.
What package type does the 93AA66A-I/ST use?
The 93AA66A-I/ST uses an 8-pin TSSOP package (ST suffix), measuring 3.0 mm × 4.4 mm with 0.65 mm lead pitch. It is RoHS-compliant with matte tin finish and features two NC pins (Pins 6 and 7) - confirming the absence of ORG functionality. Pin 1 is laser-marked for orientation identification, and no exposed thermal pad is present.
Can the 93AA66A-I/ST perform bulk erase and write operations?
Yes, the 93AA66A-I/ST supports both Erase All (ERAL) and Write All (WRAL) commands. ERAL clears the entire 512-byte array to 0xFF in one self-timed 6 ms cycle; WRAL automatically executes ERAL first, then writes the supplied 8-bit data to all locations - completing in 15 ms. Both require VCC ≥4.5 V for reliable execution per DS21795E Section 2.5 and 2.9.
93AA66A-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:
- 512 x 8
- Memory Interface:
- Microwire
- Clock Frequency:
- 2 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
93AA66A-I/ST FAQ
1.How can I place an order for 93AA66A-I/ST through Aetrix?
Please submit a Request for Quotation (RFQ) for 93AA66A-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 93AA66A-I/ST reliable?
The price and inventory of 93AA66A-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 93AA66A-I/ST is usually 5 days.
3.What payment methods are accepted for 93AA66A-I/ST?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for 93AA66A-I/ST transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for 93AA66A-I/ST?
93AA66A-I/ST orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your 93AA66A-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 93AA66A-I/ST?
For technical support, including 93AA66A-I/ST datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your 93AA66A-I/ST requirements.
6.How does Aetrix verify that 93AA66A-I/ST is sourced from the original manufacturer or authorized distributors?
All 93AA66A-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 93AA66A-I/ST meets industry standards.
7.What is the process for return or replacement of 93AA66A-I/ST?
All 93AA66A-I/ST units undergo pre-shipment inspection (PSI). If there is an issue with 93AA66A-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 93AA66A-I/ST part is unused and in its original packaging.
Return procedure for 93AA66A-I/ST:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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