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

Microchip Technology 93C66CT-E/SN

Name: 93C66CT-E/SN
Brand: Microchip Technology
SKU: 93C66CT-E/SN
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: 93C66CT-E/SN

Manufacturer:: Microchip Technology

Category:: Memory

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

Datasheet:: 93C66CT-E/SN.pdf

Description:: IC EEPROM 4KBIT MICROWIRE 8SOIC

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Product details

Overview

93C66CT-E/SN from Microchip Technology Inc. is a 4 Kbit serial EEPROM with Microwire-compatible 3-wire interface, fixed 8-bit organization (no ORG pin), 4.5–5.5 V supply range, and automotive-grade temperature operation (–40°C to +125°C). It delivers 1 million erase/write cycles, >200-year data retention, and integrated power-on/off data protection - used for parameter storage in engine control units, ABS modules, and automotive infotainment systems.

For engineers reviewing the 93C66CT-E/SN datasheet, 93C66CT-E/SN pinout, 93C66CT-E/SN application, or 93C66CT-E/SN equivalent, key selection factors include its automotive temperature rating, dedicated 8-bit x 512-word memory map, self-timed write/erase with ERAL/WRAL support, and compatibility with legacy Microwire controllers requiring minimal firmware changes.

Technical Context

This device implements a synchronous serial interface with CS, CLK, and DI/DO pins, using start-bit detection and opcode-based command execution (READ, WRITE, ERASE, ERAL, WRAL, EWEN/EWDS). It operates exclusively in 8-bit mode (ORG pin not present), with all instructions executed via rising-edge clocked bit streams and Ready/Busy status reported on DO during programming.

Power management includes automatic low-power standby when CS is low, POR detection at 3.8 V, and hardware-enforced write protection: device powers up in EWDS state, requiring explicit EWEN before any erase/write, and supports automatic ERAL prior to WRAL. Write cycle time is 2 ms (93C-series), distinct from 6 ms for AA/LC variants.

Key Specifications

Parameter	Value and Actual Design Meaning
Memory size	4 Kbit (512 × 8-bit organization)
V_CC range	4.5 V to 5.5 V - requires stable regulated rail; POR threshold at 3.8 V prevents spurious writes during brown-out
Temperature grade	Automotive (–40°C to +125°C) - qualified for under-hood and safety-critical ECUs
Endurance	1,000,000 erase/write cycles - supports frequent calibration or fault-log updates over vehicle lifetime
Data retention	>200 years at +125°C - ensures nonvolatile storage integrity across full automotive service life
Write cycle time	2 ms (T_WC) - enables fast parameter updates without blocking host MCU for extended periods
Interface	Microwire-compatible 3-wire serial (CS/CLK/DI/DO) - interoperable with legacy microcontrollers lacking SPI hardware

Pinout & Package

93C66CT-E/SN is packaged in an 8-lead SOIC (SN) with Pb-free Matte Tin finish. Pin 1 is CS; pin 2 is CLK; pin 3 is DI; pin 4 is DO; pin 5 is VSS; pin 6 is NC (no internal connection); pin 7 is NC (no internal connection); pin 8 is VCC. The ORG pin is absent - confirming fixed 8-bit operation per 'A' variant designation.

Pin/Terminal	Circuit Role	Design Meaning
CS (Pin 1)	Chip Select	Active-high enable: must be held ≥250 ns low between commands; initiates self-timed write on falling edge for 93C-series
CLK (Pin 2)	Serial Clock	Rising-edge synchronized I/O; clocking stops during auto-erase/write; TCKH/TCKL minima vary by V_CC
DI (Pin 3)	Data Input	Receives start bit, opcodes, addresses, and write data; high-impedance when not selected
DO (Pin 4)	Data Output / Status	Outputs read data or Ready/Busy (low = busy); enters High-Z on CS falling edge
VSS (Pin 5)	Ground	Reference for all I/O and internal logic; must be low-impedance path to system ground plane
NC (Pin 6 & 7)	No Connection	Unused silicon pads - must remain unconnected; no pull-up/down required
VCC (Pin 8)	Power Supply	4.5–5.5 V only; POR circuit disables writes below 3.8 V; decoupling capacitor mandatory

Key Features

Feature	Design Value
Auto-erase before write	Eliminates need for separate ERASE command - simplifies firmware and guarantees data consistency
ERAL and WRAL commands	Enables full-array erase or write in single instruction - critical for factory calibration reset or firmware recovery
Hardware write protection	EWEN/EWDS lock prevents accidental writes; powers up in EWDS state - enhances field reliability
Ready/Busy polling	DO pin provides real-time status without interrupt or timer dependency - reduces MCU resource load
Pb-free & RoHS compliant	Matte Tin finish meets automotive ELV and global environmental compliance requirements

Applications

Engine Control Unit (ECU)	Anti-lock Braking System (ABS)
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 parameter register accessed asynchronously during idle or post-run phases; supports burst reads and infrequent writes. Use Value: 1M endurance and >200-year retention ensure calibration data survives 15+ year vehicle lifetimes without corruption.	Use Scenario: Logging wheel speed sensor faults, brake pressure thresholds, and ABS activation history for service diagnostics. IC Role / Device Role / Timing Role: Dedicated fault-event logger with deterministic 2 ms write latency - avoids MCU timing jitter during braking events. Use Value: Automotive temperature rating (–40°C to +125°C) guarantees operation inside brake control module enclosures near hot calipers.
Infotainment Head Unit	Body Control Module (BCM)
Use Scenario: Retaining user preferences (volume, EQ settings, radio presets) and Bluetooth pairing tables after battery disconnect. IC Role / Device Role / Timing Role: Low-power configuration store accessed during boot; standby current ≤5 µA minimizes parasitic drain. Use Value: Power-on/off data protection circuitry prevents corruption during vehicle jump-starts or alternator transients.	Use Scenario: Storing door lock/unlock patterns, window position limits, and lighting timeout configurations across vehicle platforms. IC Role / Device Role / Timing Role: Shared configuration hub for multiple CAN nodes; accessed via discrete GPIO-controlled Microwire bus. Use Value: Fixed 8-bit interface simplifies integration with cost-sensitive 8-bit MCUs common in BCM designs.

Engine Control Unit (ECU)

Anti-lock Braking System (ABS)

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 parameter register accessed asynchronously during idle or post-run phases; supports burst reads and infrequent writes.

Use Value: 1M endurance and >200-year retention ensure calibration data survives 15+ year vehicle lifetimes without corruption.

Use Scenario: Logging wheel speed sensor faults, brake pressure thresholds, and ABS activation history for service diagnostics.

IC Role / Device Role / Timing Role: Dedicated fault-event logger with deterministic 2 ms write latency - avoids MCU timing jitter during braking events.

Use Value: Automotive temperature rating (–40°C to +125°C) guarantees operation inside brake control module enclosures near hot calipers.

Infotainment Head Unit

Body Control Module (BCM)

Use Scenario: Retaining user preferences (volume, EQ settings, radio presets) and Bluetooth pairing tables after battery disconnect.

IC Role / Device Role / Timing Role: Low-power configuration store accessed during boot; standby current ≤5 µA minimizes parasitic drain.

Use Value: Power-on/off data protection circuitry prevents corruption during vehicle jump-starts or alternator transients.

Use Scenario: Storing door lock/unlock patterns, window position limits, and lighting timeout configurations across vehicle platforms.

IC Role / Device Role / Timing Role: Shared configuration hub for multiple CAN nodes; accessed via discrete GPIO-controlled Microwire bus.

Use Value: Fixed 8-bit interface simplifies integration with cost-sensitive 8-bit MCUs common in BCM designs.

Equivalent & Alternatives

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

Alternative Part	Technical Difference	Application Difference	Selection Advice
93C66B-E/SN	16-bit organization (x256), same V_CC/temp specs, identical package - ORG pin absent but internal mapping differs	Requires host firmware rework for 16-bit addressing and data framing; incompatible with existing 8-bit drivers	Select only if migrating to wider word access and redesigning controller interface logic
AT25DF041A-SHN-T	SPI interface (4-wire), 4 Mbit density, 2.7–3.6 V supply, industrial temp only - no Microwire compatibility	Not drop-in: needs SPI master, different command set, and voltage translation for 5 V systems	Consider for new designs prioritizing higher density and faster throughput, not for 93C66CT-E/SN replacement

Compared with 93C66B-E/SN and AT25DF041A-SHN-T, the 93C66CT-E/SN uniquely combines automotive qualification, Microwire compatibility, fixed 8-bit operation, and 4.5–5.5 V native support - making it irreplaceable in legacy 5 V automotive subsystems without interface redesign.

Availability

93C66CT-E/SN is available at Aetrix Electronics and suitable for engine control units, anti-lock braking systems, and infotainment head units requiring stable component supply across extended automotive production lifecycles.

Supply support for 93C66CT-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, serving automotive, industrial, and consumer markets with high-reliability semiconductor products.

The 93C66CT-E/SN belongs to Microchip's legacy 93XX serial EEPROM family, designed specifically for cost-sensitive, low-pin-count automotive and industrial applications requiring robust nonvolatile storage with minimal external components.

FAQ

What is the memory organization of the 93C66CT-E/SN?

The 93C66CT-E/SN has a fixed 512 × 8-bit organization (x8 mode). It is an 'A'-variant device, meaning the ORG pin is not implemented - eliminating configuration ambiguity and ensuring deterministic 8-bit data framing without external logic.

Does the 93C66CT-E/SN support 16-bit operation?

No. The 93C66CT-E/SN does not support 16-bit operation. Its part number suffix 'A' and absence of ORG pin confirm exclusive 8-bit interface. For 16-bit capability, Microchip offers the 93C66B-E/SN (x256) or 93C66C-E/SN (pin-configurable x8/x16).

What is the minimum V_CC required for reliable write operations on the 93C66CT-E/SN?

The 93C66CT-E/SN requires V_CC ≥ 4.5 V for all operations, with a power-on reset (POR) threshold of 3.8 V. Writes are inhibited below this threshold - preventing data corruption during power ramp-up or brown-out conditions in automotive electrical systems.

How does write protection work on the 93C66CT-E/SN?

The 93C66CT-E/SN powers up in Erase/Write Disable (EWDS) mode. An explicit EWEN command must precede any ERASE or WRITE instruction. After each write, issuing EWDS re-enables hardware protection - a critical safeguard against firmware bugs or EMI-induced spurious commands.

Is the 93C66CT-E/SN pin-compatible with other 93XX66 devices in SOIC-8 packaging?

Yes - the 93C66CT-E/SN shares identical 8-lead SOIC (SN) pinout with all 93XX66A/B/C variants, including CS/CLK/DI/DO/VSS/NC/NC/VCC mapping. However, functional compatibility depends on organization (A/B/C), V_CC range, and temperature grade - verify datasheet tables before substitution.

93C66CT-E/SN Specifications

Product attributes: Attribute value

Manufacturer:: Microchip Technology

Series:: -

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

93C66CT-E/SN FAQ

1.How can I place an order for 93C66CT-E/SN through Aetrix?

Please submit a Request for Quotation (RFQ) for 93C66CT-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 93C66CT-E/SN reliable?

The price and inventory of 93C66CT-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 93C66CT-E/SN is usually 5 days.

3.What payment methods are accepted for 93C66CT-E/SN?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for 93C66CT-E/SN transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for 93C66CT-E/SN?

93C66CT-E/SN orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your 93C66CT-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 93C66CT-E/SN?

For technical support, including 93C66CT-E/SN datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your 93C66CT-E/SN requirements.

6.How does Aetrix verify that 93C66CT-E/SN is sourced from the original manufacturer or authorized distributors?

All 93C66CT-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 93C66CT-E/SN meets industry standards.

7.What is the process for return or replacement of 93C66CT-E/SN?

All 93C66CT-E/SN units undergo pre-shipment inspection (PSI). If there is an issue with 93C66CT-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 93C66CT-E/SN part is unused and in its original packaging.

Return procedure for 93C66CT-E/SN:

1.Submit a request within 90 days.

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

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