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

Microchip Technology 93C66A-E/SN

Name: 93C66A-E/SN
Brand: Microchip Technology
SKU: 93C66A-E/SN
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: 93C66A-E/SN

Manufacturer:: Microchip Technology

Category:: Memory

Package:: 8-SOIC (0.154", 3.90mm Width)

Datasheet:: 93C66A-E/SN.pdf

Description:: IC EEPROM 4KBIT MICROWIRE 8SOIC

Quantity:: RFQ Add To RFQ list

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Product details

Overview

93C66A-E/SN from Microchip Technology Inc. is a 4 Kbit (512 × 8-bit) low-voltage serial EEPROM with Microwire-compatible 3-wire interface, 4.5–5.5 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 93C66A-E/SN datasheet, 93C66A-E/SN pinout, 93C66A-E/SN application, or 93C66A-E/SN equivalent, key selection considerations include its fixed 8-bit organization (no ORG pin), 2 ms typical write cycle time, 1 million endurance cycles, 200-year data retention, and compatibility with legacy Microwire controllers in space-constrained industrial modules.

Technical Context

The 93C66A-E/SN implements a synchronous serial interface using CS, CLK, and DI/DO lines with start-bit detection and opcode-driven command execution. Its internal architecture includes an address decoder, mode decode logic, and output buffer, supporting READ, WRITE, ERASE, ERAL, WRAL, EWEN, and EWDS instructions - all clocked on CLK rising edges.

Unlike C-variant parts, the 93C66A-E/SN lacks an ORG pin (NC), fixing memory organization to 512 × 8-bit. Write initiation occurs on the rising edge of CLK at the final data bit, and Ready/Busy status is polled via DO while CS is high after ≥250 ns low time (TCSL).

Key Specifications

Parameter	Value and Actual Design Meaning
Memory Size	4 Kbit (512 words × 8 bits) - supports compact nonvolatile storage for boot parameters or device IDs in microcontroller-based systems.
V_CC Range	4.5 V to 5.5 V - designed for stable operation in 5 V rail environments with built-in POR at 3.8 V threshold.
Write Cycle Time	2 ms typical - enables fast field updates without blocking host MCU for extended periods.
Endurance	1,000,000 erase/write cycles - suitable for applications requiring frequent reconfiguration, such as industrial HMI settings or calibration logs.
Data Retention	>200 years at +25°C - ensures long-term reliability in unattended equipment like utility meters or remote sensors.
Interface	Microwire-compatible 3-wire serial (CS/CLK/DI/DO) - interoperable with legacy PIC® MCU peripherals and simple GPIO bit-banged controllers.
Temp Range	−40°C to +125°C (Automotive grade E) - qualified for under-hood or motor-control applications with thermal cycling stress.

Pinout & Package

Package: 8-lead SOIC (SN), Pb-free Matte Tin finish, body size 3.9 mm × 4.9 mm, standard JEDEC MS-012AA footprint.

Pin/Terminal	Circuit Role	Design Meaning
1 CS	Chip Select	Active-high enable; must be held low ≥250 ns between commands; deselects device into standby but allows ongoing write completion.
2 CLK	Serial Clock	Synchronizes all data transfers; rising edge clocks in opcodes, addresses, and data; stoppable at any level for host flexibility.
3 DI	Data Input	Receives start bit, instruction opcodes, address bits, and write data; shares no internal conflict with DO in standard use.
4 DO	Data Output / Status	Outputs read data or Ready/Busy signal (low = busy); enters High-Z when CS is low or during non-read operations.
5 VSS	Ground	Reference return path for all I/O and core logic; requires low-impedance connection to minimize noise coupling.
6 NC	No Connect	Internally unconnected; must be left floating or tied to VSS per layout best practice - not usable as ORG (absent in A/B variants).
7 NC	No Connect	Unused pin; electrically isolated - no routing or soldering required; avoids unintended parasitic coupling.
8 VCC	Power Supply	4.5–5.5 V supply input; includes internal voltage detect (VPOR = 3.8 V) for automatic data protection during brownout.

Key Features

Feature	Design Value
Self-timed Erase/Write	Eliminates external timing control - host only waits for DO polling or fixed 2 ms timeout, simplifying firmware design.
Automatic ERAL before WRAL	Guarantees full-array readiness prior to bulk write, preventing partial writes and ensuring deterministic initialization behavior.
Power-On/Off Data Protection	Hardware-level lockout below 3.8 V prevents corruption during power ramp-up/down - no software safeguards needed.
Ready/Busy Status via DO	Enables efficient polling without dedicated status lines - reduces pin count and PCB routing complexity in resource-limited designs.
Industry Standard Microwire Interface	Ensures drop-in compatibility with existing 3-wire controller IP blocks and driver libraries across multiple MCU families.

Applications

Industrial Sensor Node	Automotive Body Control Module
Use Scenario: Storing calibrated offset/gain values and fault history in a temperature/humidity sensor node deployed in factory automation. IC Role / Device Role / Timing Role: Nonvolatile configuration register holding sensor-specific trim coefficients updated during factory calibration and field maintenance. Use Value: Maintains accuracy over 200+ years without battery backup; withstands 1M write cycles during recalibration events.	Use Scenario: Retaining user preferences (seat position, mirror angle, lighting profiles) in a BCM subjected to automotive thermal cycling and vibration. IC Role / Device Role / Timing Role: Dedicated parameter store accessed during power-up and runtime via Microwire interface from main MCU. Use Value: −40°C to +125°C rating ensures reliable operation under hood; 5.5 V tolerance accommodates load-dump transients.
Medical Infusion Pump	Smart Energy Meter
Use Scenario: Logging dose history, alarm thresholds, and calibration timestamps in a Class II medical device requiring traceable data integrity. IC Role / Device Role / Timing Role: Secure audit trail storage with hardware write-protection (EWDS/EWEN) and power-fail safety. Use Value: Built-in ERAL/WRAL commands simplify firmware update sequences; RoHS/Pb-free compliance meets IEC 60601-1 requirements.	Use Scenario: Holding tariff tables, meter ID, and tamper-event counters in a DIN-rail mounted electricity meter operating continuously for 15+ years. IC Role / Device Role / Timing Role: Long-life configuration and event log memory interfaced to an 8-bit MCU with limited peripheral resources. Use Value: 200-year retention eliminates need for periodic data refresh; SOIC-8 package enables automated assembly and rework.

Industrial Sensor Node

Automotive Body Control Module

Use Scenario: Storing calibrated offset/gain values and fault history in a temperature/humidity sensor node deployed in factory automation.

IC Role / Device Role / Timing Role: Nonvolatile configuration register holding sensor-specific trim coefficients updated during factory calibration and field maintenance.

Use Value: Maintains accuracy over 200+ years without battery backup; withstands 1M write cycles during recalibration events.

Use Scenario: Retaining user preferences (seat position, mirror angle, lighting profiles) in a BCM subjected to automotive thermal cycling and vibration.

IC Role / Device Role / Timing Role: Dedicated parameter store accessed during power-up and runtime via Microwire interface from main MCU.

Use Value: −40°C to +125°C rating ensures reliable operation under hood; 5.5 V tolerance accommodates load-dump transients.

Medical Infusion Pump

Smart Energy Meter

Use Scenario: Logging dose history, alarm thresholds, and calibration timestamps in a Class II medical device requiring traceable data integrity.

IC Role / Device Role / Timing Role: Secure audit trail storage with hardware write-protection (EWDS/EWEN) and power-fail safety.

Use Value: Built-in ERAL/WRAL commands simplify firmware update sequences; RoHS/Pb-free compliance meets IEC 60601-1 requirements.

Use Scenario: Holding tariff tables, meter ID, and tamper-event counters in a DIN-rail mounted electricity meter operating continuously for 15+ years.

IC Role / Device Role / Timing Role: Long-life configuration and event log memory interfaced to an 8-bit MCU with limited peripheral resources.

Use Value: 200-year retention eliminates need for periodic data refresh; SOIC-8 package enables automated assembly and rework.

Equivalent & Alternatives

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

Alternative Part	Technical Difference	Application Difference	Selection Advice
93LC66A-E/SN	V_CC range 2.5–5.5 V; same 512 × 8-bit organization; supports wider voltage headroom for mixed-supply systems.	Preferred where 3.3 V or dual-rail (3.3 V/5 V) operation is required; not rated for 125°C automotive use.	Select 93LC66A-E/SN if system operates below 4.5 V or requires extended temperature margin at lower voltages.
AT25040B-MAHL-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.	Better suited for high-speed SPI hosts; lacks hardware VPOR lockout below 3.8 V and auto-ERAL before WRAL.	Choose AT25040B-MAHL-T when migrating to SPI infrastructure or needing faster random access than Microwire permits.

Compared with 93LC66A-E/SN and AT25040B-MAHL-T, the 93C66A-E/SN delivers guaranteed automotive-grade thermal performance and deterministic 2 ms write timing with integrated power-fail protection - making it optimal for safety-critical 5 V systems where interface simplicity and robustness outweigh raw speed.

Availability

93C66A-E/SN is available at Aetrix Electronics and suitable for industrial sensor nodes, automotive body control modules, medical infusion pumps, and smart energy meters requiring stable component supply across extended product lifecycles.

Supply support for 93C66A-E/SN 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, manufacturing, and sales operations.

The 93C66A-E/SN belongs to Microchip's legacy 93XX serial EEPROM family, engineered for cost-sensitive, low-pin-count embedded systems requiring proven reliability, wide temperature operation, and Microwire protocol compatibility.

FAQ

What is the memory organization of the 93C66A-E/SN?

The 93C66A-E/SN has a fixed 512 × 8-bit organization. Unlike C-variant parts, it does not feature an ORG pin - pins 6 and 7 are No Connect (NC), and memory width is permanently configured for byte-oriented access. This eliminates external configuration logic and simplifies PCB layout for 8-bit host interfaces.

Does the 93C66A-E/SN support 3.3 V operation?

No, the 93C66A-E/SN requires a minimum V_CC of 4.5 V and operates up to 5.5 V. It is not compatible with 3.3 V systems. For 2.5–5.5 V operation, consider the functionally identical 93LC66A-E/SN, which shares the same 512 × 8-bit structure and pinout but extends voltage range downward.

How is write protection implemented on the 93C66A-E/SN?

Write protection is enforced through hardware voltage detection (VPOR = 3.8 V) and software-controlled EWEN/EWDS commands. The device powers up in EWDS (Erase/Write Disable) mode; an EWEN instruction must precede any ERASE or WRITE. After each write, issuing EWDS restores protection - preventing accidental overwrites during noise events or power glitches.

What is the maximum clock frequency supported by the 93C66A-E/SN?

The 93C66A-E/SN supports up to 3 MHz clock frequency when V_CC is 4.5–5.5 V. AC timing parameters including TCKH (200 ns min), TCKL (100 ns min), and TPD (200 ns max) are specified under these conditions, enabling reliable communication with standard 5 V microcontrollers and FPGA I/O blocks.

Can the 93C66A-E/SN be used in automotive applications?

Yes, the 93C66A-E/SN is qualified for Automotive (E) temperature range (−40°C to +125°C) and carries the "E" suffix in its part number. It meets AEC-Q100 stress test requirements for ambient temperature, thermal cycling, and humidity exposure - making it suitable for body electronics, infotainment, and powertrain subsystems where EEPROM reliability is critical.

93C66A-E/SN Specifications

Product attributes: Attribute value

Manufacturer:: Microchip Technology

Series:: -

Package/Case:: 8-SOIC (0.154", 3.90mm 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:: 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-SOIC

93C66A-E/SN FAQ

1.How can I place an order for 93C66A-E/SN through Aetrix?

Please submit a Request for Quotation (RFQ) for 93C66A-E/SN 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 93C66A-E/SN reliable?

The price and inventory of 93C66A-E/SN are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for 93C66A-E/SN is usually 5 days.

3.What payment methods are accepted for 93C66A-E/SN?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for 93C66A-E/SN transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for 93C66A-E/SN?

93C66A-E/SN orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your 93C66A-E/SN 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 93C66A-E/SN?

For technical support, including 93C66A-E/SN datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your 93C66A-E/SN requirements.

6.How does Aetrix verify that 93C66A-E/SN is sourced from the original manufacturer or authorized distributors?

All 93C66A-E/SN 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 93C66A-E/SN meets industry standards.

7.What is the process for return or replacement of 93C66A-E/SN?

All 93C66A-E/SN units undergo pre-shipment inspection (PSI). If there is an issue with 93C66A-E/SN, 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 93C66A-E/SN part is unused and in its original packaging.

Return procedure for 93C66A-E/SN:

1.Submit a request within 90 days.

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

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