AT93C66-10SC-2.7 EEPROM Memory IC Equivalent & Substitute Parts

Part Overview

The AT93C66-10SC-2.7 is a 4Kbit EEPROM memory IC manufactured by Microchip Technology, featuring 3-Wire Serial interface with 2 MHz clock frequency and 8-SOIC surface mount packaging. This part is classified as obsolete, making equivalent and substitute parts necessary for new designs and ongoing production requirements. The 4Kbit capacity with 512 x 8 or 256 x 16 memory organization serves applications requiring non-volatile serial memory storage in compact form factors.

Key Parameters

Parameter	Value
Memory Size	4Kbit
Memory Organization	512 x 8, 256 x 16
Memory Interface	3-Wire Serial
Clock Frequency	2 MHz
Write Cycle Time	10ms
Voltage Supply Range	2.7V ~ 5.5V
Operating Temperature	0°C ~ 70°C
Package / Case	8-SOIC (0.154", 3.90mm Width)
Mounting Type	Surface Mount
RoHS Status	RoHS non-compliant

Substitute Part Grouping Explanation

Substitution for the AT93C66-10SC-2.7 is determined by the following critical parameters:

Primary Compatibility Criteria:

Memory Size: 4Kbit (mandatory match)
Memory Organization: 512 x 8 or 256 x 16 (mandatory match)
Package / Case: 8-SOIC form factor (mandatory match)
Memory Interface: 3-Wire Serial or Microwire (functionally compatible serial protocols)
Voltage Supply Range: Must encompass or overlap with 2.7V ~ 5.5V
Operating Temperature: Must support minimum 0°C ~ 70°C range

Secondary Compatibility Factors:

Clock Frequency: 2 MHz or higher (backward compatible)
Write Cycle Time: 10ms or faster (performance improvement acceptable)
RoHS Compliance: Active parts preferred for new designs
Product Status: Active status preferred over obsolete

All substitute parts listed maintain identical memory capacity, organization, and 8-SOIC packaging. Interface compatibility is achieved through Microwire protocol support, which is functionally compatible with 3-Wire Serial applications. Voltage and temperature ranges of substitutes either match or exceed the original specification.

Parameter Comparison

Parameter	AT93C66-10SC-2.7	93AA66CT-I/SN	CAT93C66VI-G	CAT93C66VI-GT3	M93C66-RMN3TP/K	M93C66-WMN6P	M93C66-WMN6TP
Manufacturer	Microchip Technology	Microchip Technology	onsemi	onsemi	STMicroelectronics	STMicroelectronics	STMicroelectronics
Memory Size	4Kbit	4Kbit	4Kbit	4Kbit	4Kbit	4Kbit	4Kbit
Memory Organization	512 x 8, 256 x 16	512 x 8, 256 x 16	512 x 8, 256 x 16	512 x 8, 256 x 16	512 x 8, 256 x 16	512 x 8, 256 x 16	512 x 8, 256 x 16
Memory Interface	3-Wire Serial	Microwire	Microwire	Microwire	Microwire	Microwire	Microwire
Clock Frequency	2 MHz	3 MHz	2 MHz	2 MHz	2 MHz	2 MHz	2 MHz
Write Cycle Time	10ms	6ms	—	—	5ms	5ms	5ms
Voltage Supply Range	2.7V ~ 5.5V	1.8V ~ 5.5V	1.8V ~ 5.5V	1.8V ~ 5.5V	1.8V ~ 5.5V	2.5V ~ 5.5V	2.5V ~ 5.5V
Operating Temperature	0°C ~ 70°C	-40°C ~ 85°C	-40°C ~ 85°C	-40°C ~ 85°C	-40°C ~ 125°C	-40°C ~ 85°C	-40°C ~ 85°C
Package / Case	8-SOIC	8-SOIC	8-SOIC	8-SOIC	8-SOIC	8-SOIC	8-SOIC
Product Status	Obsolete	Active	Active	Active	Active	Active	Active
RoHS Status	RoHS non-compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant

Engineering Selection Recommendations

Primary Recommendation: 93AA66CT-I/SN (Microchip Technology)

The 93AA66CT-I/SN is the manufacturer-recommended primary substitute. It maintains Microchip Technology as the original manufacturer, ensuring design continuity and supply chain consistency. This part is active, ROHS3 compliant, and offers improved performance with 3 MHz clock frequency and 6ms write cycle time. Voltage supply range (1.8V ~ 5.5V) encompasses the original specification. Operating temperature range (-40°C ~ 85°C) exceeds the original requirement.

Secondary Recommendations: CAT93C66VI-G and CAT93C66VI-GT3 (onsemi)

Both onsemi parts provide active status and ROHS3 compliance. CAT93C66VI-GT3 offers higher inventory availability (24,792 pcs) in Tape & Reel packaging, suitable for high-volume production. CAT93C66VI-G is available in Tube packaging. Both maintain 2 MHz clock frequency matching the original specification and support the required voltage and temperature ranges.

Automotive-Grade Option: M93C66-RMN3TP/K (STMicroelectronics)

For applications requiring automotive qualification, M93C66-RMN3TP/K provides AEC-Q100 certification and extended operating temperature range (-40°C ~ 125°C). This part is suitable for automotive and industrial environments requiring enhanced reliability.

High-Volume Production Options: M93C66-WMN6TP and M93C66-WMN6P (STMicroelectronics)

M93C66-WMN6TP offers the highest inventory availability (35,100 pcs) in Cut Tape & Digi-Reel packaging, optimized for automated assembly. M93C66-WMN6P provides alternative packaging in Tube format. Both are verified as DiGi-Electronics programmable and offer 5ms write cycle time improvement.

Frequently Asked Questions (FAQ)

Q: Can I use a Microwire interface part as a direct replacement for the 3-Wire Serial AT93C66-10SC-2.7?

A: Yes. Microwire is functionally compatible with 3-Wire Serial protocol for EEPROM memory applications. Both protocols support the same memory organization (512 x 8, 256 x 16) and serial communication structure. Existing firmware and hardware interfaces designed for 3-Wire Serial will operate with Microwire-based substitutes without modification.

Q: What is the impact of higher clock frequency (3 MHz vs. 2 MHz) on system compatibility?

A: Higher clock frequency is backward compatible. The 93AA66CT-I/SN operates at 3 MHz, which is faster than the original 2 MHz specification. Systems designed for 2 MHz operation will function correctly with 3 MHz parts; data transfer rates will be faster, improving overall system performance without compatibility issues.

Q: Are all substitute parts RoHS compliant?

A: All listed substitute parts are ROHS3 compliant. The original AT93C66-10SC-2.7 is RoHS non-compliant. For new designs and applications subject to RoHS regulations, any of the listed substitutes satisfy compliance requirements.

Q: Which substitute part offers the best availability for immediate production?

A: M93C66-WMN6TP (STMicroelectronics) provides the highest inventory level at 35,100 pcs in Cut Tape & Digi-Reel packaging, optimized for automated assembly lines. CAT93C66VI-GT3 (onsemi) offers 24,792 pcs in Tape & Reel format as an alternative high-availability option.

Q: Can I use parts with extended temperature ranges (-40°C ~ 125°C) in applications requiring only 0°C ~ 70°C?

A: Yes. Extended temperature range parts are fully compatible with narrower temperature requirements. M93C66-RMN3TP/K with -40°C ~ 125°C range will operate correctly in 0°C ~ 70°C applications, providing additional design margin and reliability.

Q: What is the difference between Cut Tape & Digi-Reel and Tube packaging?

A: Cut Tape & Digi-Reel packaging is optimized for automated pick-and-place assembly, suitable for high-volume production. Tube packaging is suitable for manual assembly or lower-volume applications. Both packaging formats contain identical components; selection depends on assembly process requirements.

Q: Are there any voltage supply considerations when substituting parts?

A: The original AT93C66-10SC-2.7 requires 2.7V ~ 5.5V supply. Most substitutes support 1.8V ~ 5.5V or 2.5V ~ 5.5V ranges. Verify your system supply voltage falls within the selected substitute's specification. M93C66-WMN6P and M93C66-WMN6TP require minimum 2.5V, matching the original lower limit more closely than parts supporting 1.8V minimum.

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