93C66C-E/ST EEPROM Memory IC Equivalent & Substitute Parts

Part Overview

The 93C66C-E/ST is a 4Kbit EEPROM memory IC manufactured by Microchip Technology, featuring Microwire serial interface protocol and 8-TSSOP surface mount packaging. This non-volatile memory device operates at 3 MHz clock frequency with a 4.5V to 5.5V supply voltage range and supports industrial temperature range operation from -40°C to 125°C. The part is currently in active production status with ROHS3 compliance and unlimited moisture sensitivity level rating.

Equivalent and substitute parts are identified based on matching core functional parameters: 4Kbit memory capacity, EEPROM technology, Microwire interface protocol, 8-TSSOP package form factor, and compatible operating temperature specifications.

Key Parameters

Parameter	Specification
Memory Size	4Kbit
Memory Format	EEPROM
Memory Interface	Microwire
Memory Organization	512 x 8, 256 x 16
Clock Frequency	3 MHz
Voltage Supply Range	4.5V ~ 5.5V
Operating Temperature	-40°C ~ 125°C
Package Type	8-TSSOP
Write Cycle Time	2ms
Product Status	Active

Substitute Part Grouping Explanation

Substitute parts for the 93C66C-E/ST are qualified based on the following mandatory compatibility criteria:

Core Functional Requirements:

Memory capacity: 4Kbit
Memory technology: EEPROM
Serial interface: Microwire protocol
Memory organization: 512 x 8 or 256 x 16 bit configuration
Package: 8-TSSOP form factor with 0.173" width (4.40mm)

Electrical Compatibility Criteria:

Supply voltage range must encompass or overlap with 4.5V ~ 5.5V
Operating temperature range must support -40°C minimum and 125°C maximum
Clock frequency and write cycle time parameters must be functionally compatible with system timing requirements

Manufacturing & Compliance:

ROHS3 compliance required
Active product status
Moisture sensitivity level MSL-1 (unlimited)

The identified substitute parts meet these criteria while originating from different manufacturers (STMicroelectronics) or featuring alternative packaging configurations (Tape & Reel, Cut Tape & Digi-Reel).

Parameter Comparison

Parameter	93C66C-E/ST (Microchip)	M93C66-RDW3TP/K (STMicroelectronics)	M93C66-WDW6TP (STMicroelectronics)
Memory Size	4Kbit	4Kbit	4Kbit
Memory Format	EEPROM	EEPROM	EEPROM
Memory Interface	Microwire	Microwire	Microwire
Memory Organization	512 x 8, 256 x 16	512 x 8, 256 x 16	512 x 8, 256 x 16
Clock Frequency	3 MHz	2 MHz	2 MHz
Voltage Supply Range	4.5V ~ 5.5V	1.8V ~ 5.5V	2.5V ~ 5.5V
Operating Temperature	-40°C ~ 125°C	-40°C ~ 125°C	-40°C ~ 85°C
Write Cycle Time	2ms	5ms	5ms
Package Type	8-TSSOP	8-TSSOP	8-TSSOP
Packaging Format	Tube	Tape & Reel (TR)	Cut Tape (CT) & Digi-Reel®
RoHS Status	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant
Product Status	Active	Active	Active

Engineering Selection Recommendations

M93C66-RDW3TP/K (STMicroelectronics): This substitute part maintains full compatibility with the 93C66C-E/ST across all core functional parameters. The extended supply voltage range (1.8V ~ 5.5V) provides additional design flexibility. The part carries AEC-Q100 automotive qualification and Automotive grade designation, indicating enhanced reliability screening. Operating temperature range matches the original specification (-40°C ~ 125°C). The 2 MHz clock frequency and 5ms write cycle time are functionally compatible with systems designed for the 3 MHz / 2ms original part. Available in Tape & Reel packaging format.

M93C66-WDW6TP (STMicroelectronics): This substitute part matches all core functional requirements with identical memory capacity, interface protocol, and package form factor. The supply voltage range (2.5V ~ 5.5V) encompasses the original 4.5V ~ 5.5V specification. The operating temperature range is limited to -40°C ~ 85°C, which does not extend to the original 125°C maximum. This temperature limitation must be evaluated against specific application requirements. The part is verified for DiGi-Electronics programmability and available in high inventory quantity (105,200 pcs) with Cut Tape and Digi-Reel packaging options.

Frequently Asked Questions (FAQ)

Q: Can M93C66-RDW3TP/K replace 93C66C-E/ST in all applications?

A: Yes, M93C66-RDW3TP/K is functionally compatible across all core parameters. The extended supply voltage range (1.8V ~ 5.5V) and automotive qualification provide additional design margin. The 2 MHz clock frequency and 5ms write cycle time are compatible with systems designed for the original 3 MHz / 2ms specification.

Q: What is the temperature limitation of M93C66-WDW6TP?

A: M93C66-WDW6TP operates from -40°C to 85°C, which does not reach the original part's 125°C maximum. Applications requiring operation above 85°C must use 93C66C-E/ST or M93C66-RDW3TP/K.

Q: Are all substitute parts available in the same packaging format?

A: No. The original 93C66C-E/ST is supplied in Tube packaging. M93C66-RDW3TP/K is available in Tape & Reel format. M93C66-WDW6TP is available in Cut Tape and Digi-Reel packaging. Packaging format selection depends on assembly process requirements and volume specifications.

Q: Do the substitute parts maintain ROHS3 compliance?

A: Yes, both M93C66-RDW3TP/K and M93C66-WDW6TP are ROHS3 compliant with MSL-1 (unlimited) moisture sensitivity level, matching the original part's environmental compliance status.

Q: What is the significance of the 2 MHz vs. 3 MHz clock frequency difference?

A: The substitute parts operate at 2 MHz clock frequency compared to the original 3 MHz. This represents a lower maximum data rate. Systems designed for 3 MHz operation will function correctly at 2 MHz, as the lower frequency is backward compatible. However, applications requiring maximum 3 MHz throughput must use the original 93C66C-E/ST.

Q: Is M93C66-RDW3TP/K suitable for automotive applications?

A: Yes, M93C66-RDW3TP/K carries AEC-Q100 qualification and Automotive grade designation, making it suitable for automotive-grade applications. The original 93C66C-E/ST does not carry automotive qualification.

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