AT93C66-10SC-2.5 Equivalent & Substitute Parts

Part Overview

The AT93C66-10SC-2.5 is a 4Kbit EEPROM memory IC manufactured by Microchip Technology, featuring a 3-Wire Serial interface with 2 MHz clock frequency in an 8-SOIC surface mount package. This part is classified as obsolete, which necessitates identification of functionally equivalent alternatives for new designs and ongoing production support. Substitute parts must maintain compatibility across memory capacity, interface protocol, package form factor, and electrical operating parameters to ensure direct replacement capability.

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	2.5V ~ 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 eligibility is determined by strict adherence to the following parameters:

Critical Parameters (Must Match):

Memory Size: 4Kbit
Memory Organization: 512 x 8, 256 x 16
Package / Case: 8-SOIC (0.154", 3.90mm Width)
Mounting Type: Surface Mount

Compatible Interface Protocols: The AT93C66-10SC-2.5 uses 3-Wire Serial interface. Substitute parts using Microwire protocol are functionally compatible, as Microwire is a superset of 3-Wire Serial communication that maintains backward compatibility with 3-Wire devices.

Allowable Parameter Variations:

Clock Frequency: 2 MHz or higher
Write Cycle Time: 10ms or faster
Voltage Supply Range: Must encompass or exceed 2.5V ~ 5.5V
Operating Temperature: May extend beyond 0°C ~ 70°C
Product Status: Active parts preferred over obsolete

Parameter Comparison

Part Number	Manufacturer	Memory Size	Interface	Clock Frequency	Write Cycle Time	Voltage Supply	Operating Temperature	Package	Product Status	RoHS Status
AT93C66-10SC-2.5	Microchip Technology	4Kbit	3-Wire Serial	2 MHz	10ms	2.5V ~ 5.5V	0°C ~ 70°C	8-SOIC	Obsolete	Non-compliant
93AA66/SN	Microchip Technology	4Kbit	Microwire	2 MHz	10ms	1.8V ~ 5.5V	0°C ~ 70°C	8-SOIC	Active	ROHS3 Compliant
93AA66CT-I/SN	Microchip Technology	4Kbit	Microwire	3 MHz	6ms	1.8V ~ 5.5V	-40°C ~ 85°C	8-SOIC	Active	ROHS3 Compliant
CAT93C66VI-G	onsemi	4Kbit	Microwire	2 MHz	—	1.8V ~ 5.5V	-40°C ~ 85°C	8-SOIC	Active	ROHS3 Compliant
CAT93C66VI-GT3	onsemi	4Kbit	Microwire	2 MHz	—	1.8V ~ 5.5V	-40°C ~ 85°C	8-SOIC	Active	ROHS3 Compliant
M93C66-RMN3TP/K	STMicroelectronics	4Kbit	Microwire	2 MHz	5ms	1.8V ~ 5.5V	-40°C ~ 125°C	8-SOIC	Active	ROHS3 Compliant
M93C66-WMN6P	STMicroelectronics	4Kbit	Microwire	2 MHz	5ms	2.5V ~ 5.5V	-40°C ~ 85°C	8-SOIC	Active	ROHS3 Compliant
M93C66-WMN6TP	STMicroelectronics	4Kbit	Microwire	2 MHz	5ms	2.5V ~ 5.5V	-40°C ~ 85°C	8-SOIC	Active	ROHS3 Compliant

Engineering Selection Recommendations

All identified substitute parts are active products with ROHS3 compliance, addressing the obsolescence and regulatory limitations of the AT93C66-10SC-2.5.

Microchip Technology 93AA66 Series: The 93AA66/SN and 93AA66CT-I/SN maintain Microchip sourcing continuity. The 93AA66CT-I/SN offers enhanced performance with 3 MHz clock frequency and 6ms write cycle time, along with extended operating temperature range (-40°C to 85°C) and unlimited moisture sensitivity rating.

onsemi CAT93C66 Series: The CAT93C66VI-G and CAT93C66VI-GT3 provide cross-manufacturer alternatives with extended temperature range (-40°C to 85°C) and lower supply voltage floor (1.8V). Packaging differentiation exists between tube (VI-G) and tape & reel (VI-GT3) formats.

STMicroelectronics M93C66 Series: The M93C66-RMN3TP/K qualifies for automotive applications with AEC-Q100 certification and extended temperature range to 125°C. The M93C66-WMN6P and M93C66-WMN6TP variants maintain the original supply voltage range (2.5V ~ 5.5V) with improved write cycle time (5ms) and extended operating temperature (-40°C to 85°C).

Frequently Asked Questions (FAQ)

Q: Why is the AT93C66-10SC-2.5 classified as obsolete? A: The AT93C66-10SC-2.5 is an older generation EEPROM that is no longer in active production. Microchip Technology has transitioned to newer memory architectures. Active alternatives with equivalent or superior specifications are available from multiple manufacturers.

Q: Can Microwire interface parts directly replace 3-Wire Serial parts? A: Yes. Microwire protocol is a superset of 3-Wire Serial communication. Devices using Microwire interface maintain full backward compatibility with 3-Wire Serial protocol, allowing direct functional replacement in existing designs.

Q: What is the difference between the packaging options (Tube, Cut Tape, Tape & Reel)? A: Packaging affects order quantity and handling. Tube packaging is suitable for smaller quantities and manual assembly. Cut Tape (CT) & Digi-Reel® and Tape & Reel (TR) formats are optimized for automated pick-and-place assembly and higher volume production.

Q: Which substitute part best matches the original AT93C66-10SC-2.5 specifications? A: The M93C66-WMN6TP maintains the closest electrical match with identical supply voltage range (2.5V ~ 5.5V), 2 MHz clock frequency, and 8-SOIC package. It offers improved write cycle time (5ms vs. 10ms) and extended operating temperature range (-40°C to 85°C vs. 0°C to 70°C).

Q: Are all substitute parts RoHS compliant? A: Yes. All identified substitute parts are ROHS3 compliant, addressing the RoHS non-compliance limitation of the obsolete AT93C66-10SC-2.5.

Q: What is the significance of the AEC-Q100 qualification on the M93C66-RMN3TP/K? A: AEC-Q100 qualification indicates the part meets automotive industry reliability and quality standards. This variant is suitable for automotive applications requiring enhanced temperature range (-40°C to 125°C) and automotive-grade component certification.

Q: Can I use a part with a higher clock frequency as a substitute? A: Yes. The 93AA66CT-I/SN operates at 3 MHz, which exceeds the 2 MHz requirement of the original part. Higher clock frequency provides improved performance and does not create compatibility issues in designs using the original 2 MHz specification.

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