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Home > Products > Integrated Circuits (ICs) > Memory > Memory

Microchip Technology 93C66AT-E/ST

Name: 93C66AT-E/ST
Brand: Microchip Technology
SKU: 93C66AT-E/ST
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: 93C66AT-E/ST

Manufacturer:: Microchip Technology

Category:: Memory

Package:: 8-TSSOP (0.173", 4.40mm Width)

Datasheet:: 93C66AT-E/ST.pdf

Description:: IC EEPROM 4KBIT MICROWIRE 8TSSOP

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Product details

Overview

93C66AT-E/ST from Microchip Technology Inc. is a 4 Kbit serial EEPROM IC with 512 × 8-bit organization, Microwire-compatible 3-wire interface (CS/CLK/DI/DO), and industrial-temperature operation (–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 embedded system configuration storage and calibration data retention.

For engineers reviewing the 93C66AT-E/ST datasheet, 93C66AT-E/ST pinout, 93C66AT-E/ST application, or 93C66AT-E/ST equivalent, key selection criteria include V_CC range (4.5–5.5 V), absence of ORG pin (fixed x8 mode), TSSOP-8 package compatibility, and Ready/Busy status via DO pin during programming.

Technical Context

The 93C66AT-E/ST implements a synchronous serial Microwire protocol with start-bit detection, opcode-driven instruction set (READ/WRITE/ERASE/ERAL/WRAL/EWEN/EWDS), and hardware-based data protection. Its internal logic disables all write operations when V_CC falls below 3.8 V, ensuring robust power-fail safety.

It uses a dedicated 8-pin TSSOP package with fixed pinout: CS (1), CLK (2), DI (3), DO (4), V_SS (5), NC (6), V_CC (7), and NC (8). The device supports sequential read, high-Z DO during standby, and status polling via DO pin after minimum T_CSSL = 250 ns CS low time.

Key Specifications

Parameter	Value and Actual Design Meaning
Memory size	4 Kbit (512 × 8-bit) - fixed x8 organization; no ORG pin; suitable for byte-addressed firmware parameter storage.
V_CC operating range	4.5 V to 5.5 V - requires stable 5 V supply; POR threshold at 3.8 V prevents corruption during brown-out.
Interface	Microwire 3-wire serial (CS/CLK/DI/DO) - compatible with legacy microcontrollers lacking SPI hardware; no MISO/MOSI separation needed.
Write cycle time	2 ms typical - enables fast field updates without blocking host MCU for extended periods.
Endurance & retention	1,000,000 erase/write cycles; >200 years data retention - validated for long-life industrial logging and calibration memory.
Temperature grade	Industrial (–40°C to +85°C) - qualified for use in motor control, power supplies, and industrial HMI without derating.
Package	TSSOP-8 (ST suffix) - 3.0 × 4.4 mm footprint; surface-mount compatible; RoHS-compliant matte tin finish.

Pinout & Package

8-lead Thin Shrink Small Outline Package (TSSOP), Pb-free matte tin finish, body dimensions 3.0 mm × 4.4 mm × 1.2 mm, thermal pad optional.

Pin/Terminal	Circuit Role	Design Meaning
1 (CS)	Chip Select	Active-high enable; must be held low ≥250 ns between instructions; deselects device into standby (I_CCS ≤ 5 µA).
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; high-impedance when not selected.
4 (DO)	Data Output / Status	Outputs read data or Ready/Busy status (low = busy); enters High-Z on CS falling edge.
5 (V_SS)	Ground	Reference return path for all I/O and core logic; must be low-impedance connection.
6 (NC)	No Connect	Internally unconnected; must be left floating or tied to V_SS/V_CC per layout best practice.
7 (V_CC)	Power Supply	4.5–5.5 V supply input; decoupling capacitor (0.1 µF) required within 5 mm of pin.
8 (NC)	No Connect	Internally unconnected; no external connection required.

Key Features

Feature	Design Value
Self-timed erase/write	Eliminates need for external timing control - host MCU initiates command and polls DO for completion.
Automatic ERAL before WRAL	Guarantees full-array erase prior to bulk write, preventing stale data remnants in unaddressed locations.
Power-on/off data protection	Hardware lockout below 3.8 V V_CC prevents inadvertent writes during power ramp-up/down.
Ready/Busy status on DO	Enables non-blocking polling - host reads DO while performing other tasks instead of fixed delay waits.
Industry-standard 3-wire interface	Reduces GPIO count vs. SPI; simplifies integration with resource-constrained 8-bit MCUs and ASICs.

Applications

Motor Control Configuration	Industrial Sensor Calibration
Use Scenario: Storing PID coefficients, current limits, and commutation tables in BLDC motor drives. IC Role / Device Role / Timing Role: Nonvolatile configuration memory accessed at startup and updated during field service. Use Value: Enables field-upgradable tuning without firmware reflash; retains settings across 10+ year product lifetime.	Use Scenario: Saving factory-trimmed offset/gain values for analog sensor front-ends in process instrumentation. IC Role / Device Role / Timing Role: Calibration data repository with guaranteed 200-year retention and 1M-cycle rewrite endurance. Use Value: Eliminates manual potentiometer adjustment; supports automated calibration during manufacturing test.
Power Supply Trim Storage	Medical Device Parameter Backup
Use Scenario: Holding digital trim values for DC-DC converter feedback networks in telecom power modules. IC Role / Device Role / Timing Role: Low-power, high-reliability storage for critical voltage/current regulation parameters. Use Value: Maintains output accuracy over temperature and aging; immune to 5 V rail transients due to 3.8 V POR.	Use Scenario: Backing up user-configurable therapy settings (e.g., infusion rate, alarm thresholds) in portable medical pumps. IC Role / Device Role / Timing Role: Safety-critical nonvolatile memory with industrial temp rating and proven data integrity. Use Value: Ensures treatment continuity after battery replacement or power loss; meets IEC 62304 data retention requirements.

Motor Control Configuration

Industrial Sensor Calibration

Use Scenario: Storing PID coefficients, current limits, and commutation tables in BLDC motor drives.

IC Role / Device Role / Timing Role: Nonvolatile configuration memory accessed at startup and updated during field service.

Use Value: Enables field-upgradable tuning without firmware reflash; retains settings across 10+ year product lifetime.

Use Scenario: Saving factory-trimmed offset/gain values for analog sensor front-ends in process instrumentation.

IC Role / Device Role / Timing Role: Calibration data repository with guaranteed 200-year retention and 1M-cycle rewrite endurance.

Use Value: Eliminates manual potentiometer adjustment; supports automated calibration during manufacturing test.

Power Supply Trim Storage

Medical Device Parameter Backup

Use Scenario: Holding digital trim values for DC-DC converter feedback networks in telecom power modules.

IC Role / Device Role / Timing Role: Low-power, high-reliability storage for critical voltage/current regulation parameters.

Use Value: Maintains output accuracy over temperature and aging; immune to 5 V rail transients due to 3.8 V POR.

Use Scenario: Backing up user-configurable therapy settings (e.g., infusion rate, alarm thresholds) in portable medical pumps.

IC Role / Device Role / Timing Role: Safety-critical nonvolatile memory with industrial temp rating and proven data integrity.

Use Value: Ensures treatment continuity after battery replacement or power loss; meets IEC 62304 data retention requirements.

Equivalent & Alternatives

The following parts are listed as comparable options for similar serial EEPROM applications.

Alternative Part	Technical Difference	Application Difference	Selection Advice
93LC66AT-I/ST	V_CC range 2.5–5.5 V; same 512×8 organization and TSSOP-8 package; includes ORG pin (NC on this variant).	Supports wider supply range including 3.3 V systems; identical pinout and instruction set.	Select when operating from 3.3 V rails or requiring future migration to dual-voltage designs.
AT25040B-SSHL-T	SPI interface (4-wire), 512×8 capacity, 1.8–5.5 V, SOIC-8 package; no Ready/Busy pin - uses WIP flag in status register.	Requires SPI peripheral instead of generic GPIO bit-banging; lacks direct DO-status polling.	Choose for systems already using SPI peripherals and where software-controlled status checking is acceptable.

Compared with 93C66AT-E/ST, the 93LC66AT-I/ST offers broader voltage flexibility but identical functionality, while the AT25040B-SSHL-T trades Microwire simplicity for SPI standardization and lower minimum V_CC, at the cost of added software overhead for status monitoring.

Availability

93C66AT-E/ST is available at Aetrix Electronics and suitable for motor control configuration, industrial sensor calibration, and power supply trim storage requiring stable component supply across extended production lifecycles.

Supply support for 93C66AT-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 microcontroller, analog, and Flash-IP solutions, headquartered in Chandler, Arizona, with global design and manufacturing operations.

The 93Cxx series was designed specifically for cost-sensitive, low-power serial EEPROM applications in industrial, automotive, and consumer systems requiring proven reliability and Microwire compatibility.

FAQ

What is the maximum clock frequency supported by the 93C66AT-E/ST?

The 93C66AT-E/ST supports a maximum clock frequency of 3 MHz when V_CC is 4.5–5.5 V. This allows high-speed data transfer while maintaining timing margins for reliable operation in noisy industrial environments. The device remains functional down to DC clocking, enabling ultra-low-power bit-banged implementations.

Does the 93C66AT-E/ST have an ORG pin, and what does it do?

No, the 93C66AT-E/ST does not have an ORG pin - it is an 'A'-suffix device with fixed 512 × 8-bit organization. The ORG pin exists only on 'C'-suffix variants (e.g., 93C66CT-E/ST) to select between x8 and x16 modes. On the 93C66AT-E/ST, memory access is always byte-oriented with 9-bit addressing.

How is data protection implemented in the 93C66AT-E/ST during power transitions?

The 93C66AT-E/ST incorporates hardware power-on/power-off protection that inhibits all write operations when V_CC drops below 3.8 V. This threshold ensures data integrity during brown-out conditions. Additionally, the device powers up in EWDS (Erase/Write Disable) mode, requiring an explicit EWEN command before any programming - preventing accidental writes during power ramp-up.

Can the 93C66AT-E/ST be used in a 3.3 V system?

No, the 93C66AT-E/ST requires a minimum V_CC of 4.5 V and is not rated for 3.3 V operation. Attempting to operate it below 4.5 V risks data corruption and violates the absolute minimum supply specification. For 3.3 V systems, consider the pin-compatible 93LC66AT-I/ST (2.5–5.5 V range) or AT25040B-SSHL-T (1.8–5.5 V).

What is the purpose of the NC pins on the 93C66AT-E/ST TSSOP-8 package?

Pins 6 and 8 on the 93C66AT-E/ST TSSOP-8 package are No Connect (NC) terminals - internally unconnected and electrically isolated. They must be left floating in the PCB layout; tying them to V_CC or V_SS is unnecessary and may risk unintended coupling. Their presence maintains mechanical symmetry and package compatibility across the 93XX66 family.

93C66AT-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:: 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:: 2ms

Access Time:: -

Voltage - Supply:: 4.5V ~ 5.5V

Operating Temperature:: -40°C ~ 125°C (TA)

Grade:: -

Qualification:: -

Mounting Type:: Surface Mount

Supplier Device Package:: 8-TSSOP

93C66AT-E/ST FAQ

1.How can I place an order for 93C66AT-E/ST through Aetrix?

Please submit a Request for Quotation (RFQ) for 93C66AT-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 93C66AT-E/ST reliable?

The price and inventory of 93C66AT-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 93C66AT-E/ST is usually 5 days.

3.What payment methods are accepted for 93C66AT-E/ST?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for 93C66AT-E/ST transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for 93C66AT-E/ST?

93C66AT-E/ST orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your 93C66AT-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 93C66AT-E/ST?

For technical support, including 93C66AT-E/ST datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your 93C66AT-E/ST requirements.

6.How does Aetrix verify that 93C66AT-E/ST is sourced from the original manufacturer or authorized distributors?

All 93C66AT-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 93C66AT-E/ST meets industry standards.

7.What is the process for return or replacement of 93C66AT-E/ST?

All 93C66AT-E/ST units undergo pre-shipment inspection (PSI). If there is an issue with 93C66AT-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 93C66AT-E/ST part is unused and in its original packaging.

Return procedure for 93C66AT-E/ST:

1.Submit a request within 90 days.

2.Obtain a Return Material Authorization (RMA) from Aetrix.

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