93C66CT-E/ST EEPROM Memory IC Equivalent & Substitute Parts

Part Overview

The 93C66CT-E/ST is a 4Kbit non-volatile EEPROM memory IC manufactured by Microchip Technology, featuring Microwire serial interface protocol. This component is actively produced and widely used in embedded systems requiring persistent data storage with low power consumption. The part is packaged in 8-TSSOP surface mount configuration and operates across industrial temperature ranges (-40°C to 125°C). Equivalent and substitute parts are identified based on matching memory capacity, interface protocol, package type, and electrical operating parameters to ensure functional compatibility in system designs.

Key Parameters

Parameter	Specification
Memory Size	4Kbit
Memory Format	EEPROM
Memory Organization	512 x 8, 256 x 16
Memory Interface	Microwire
Clock Frequency	3 MHz
Voltage Supply Range	4.5V ~ 5.5V
Operating Temperature	-40°C ~ 125°C
Package Type	8-TSSOP (0.173", 4.40mm Width)
Write Cycle Time	2ms
RoHS Status	ROHS3 Compliant

Substitute Part Grouping Explanation

Substitute parts for the 93C66CT-E/ST are qualified based on the following critical parameters:

Memory Capacity & Organization: All substitutes maintain 4Kbit capacity with 512 x 8 or 256 x 16 organization to ensure data structure compatibility
Interface Protocol: Microwire serial interface is mandatory for protocol-level compatibility with host controllers
Package Configuration: 8-TSSOP surface mount package ensures mechanical and electrical pin compatibility with PCB layouts
Supply Voltage Range: Substitutes must operate within overlapping voltage windows to function in existing power supply designs
Temperature Rating: Operating temperature range must encompass or exceed the application's thermal requirements
RoHS Compliance: All listed substitutes maintain ROHS3 compliance for regulatory alignment

The identified substitutes from STMicroelectronics (M93C66 series) meet these core criteria while offering variations in clock frequency, write cycle timing, and voltage supply ranges that may provide advantages in specific application contexts.

Parameter Comparison

Parameter	93C66CT-E/ST (Microchip)	M93C66-RDW3TP/K (STMicroelectronics)	M93C66-WDW6TP (STMicroelectronics)
Memory Size	4Kbit	4Kbit	4Kbit
Memory Organization	512 x 8, 256 x 16	512 x 8, 256 x 16	512 x 8, 256 x 16
Memory Interface	Microwire	Microwire	Microwire
Clock Frequency	3 MHz	2 MHz	2 MHz
Write Cycle Time	2ms	5ms	5ms
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
Package Type	8-TSSOP	8-TSSOP	8-TSSOP
RoHS Status	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant
Product Status	Active	Active	Active

Engineering Selection Recommendations

M93C66-RDW3TP/K (STMicroelectronics): This substitute is qualified to AEC-Q100 automotive standards and supports an extended lower voltage supply range (1.8V minimum) compared to the primary part. The automotive-grade qualification makes this option suitable for applications requiring enhanced reliability documentation. Operating temperature range matches the primary part (-40°C to 125°C). Clock frequency is reduced to 2 MHz with corresponding 5ms write cycle time, which is acceptable for non-time-critical data storage applications.

M93C66-WDW6TP (STMicroelectronics): This substitute offers the highest inventory availability and is verified for DiGi-Electronics programmability. Supply voltage range extends to 2.5V minimum, providing flexibility for lower-power system designs. Operating temperature range is limited to -40°C to 85°C, making this option suitable only for applications not requiring the full 125°C upper temperature specification of the primary part. Clock frequency and write cycle timing are identical to the M93C66-RDW3TP/K variant.

Frequently Asked Questions (FAQ)

Q: Can M93C66-RDW3TP/K replace 93C66CT-E/ST in all applications?

A: Yes, for applications operating within -40°C to 125°C temperature range and requiring 4.5V to 5.5V supply voltage. The lower clock frequency (2 MHz vs. 3 MHz) and longer write cycle time (5ms vs. 2ms) are acceptable for most embedded systems where data write operations are not time-critical. The automotive-grade qualification provides additional reliability assurance.

Q: What is the key difference between the two STMicroelectronics substitutes?

A: M93C66-RDW3TP/K maintains the full -40°C to 125°C operating temperature range and includes AEC-Q100 automotive qualification. M93C66-WDW6TP has a reduced upper temperature limit of 85°C but offers significantly higher inventory availability and verified programmability support. Select based on temperature requirements and supply chain priorities.

Q: Are all three parts pin-compatible?

A: Yes. All three parts use identical 8-TSSOP package configuration with matching pin assignments for Microwire protocol operation. PCB layouts designed for 93C66CT-E/ST require no modification to accommodate either STMicroelectronics substitute.

Q: Does the reduced clock frequency of substitute parts affect system performance?

A: Clock frequency reduction from 3 MHz to 2 MHz affects data transfer rate during read and write operations. For applications with non-critical timing requirements or where data access is infrequent, this difference is negligible. Applications requiring maximum data throughput should retain the primary part or conduct timing analysis to confirm compatibility.

Q: Are all parts RoHS compliant?

A: Yes. The primary part (93C66CT-E/ST) and both substitutes (M93C66-RDW3TP/K and M93C66-WDW6TP) are ROHS3 compliant and REACH unaffected, meeting current environmental and regulatory requirements.

Request Quote (Ships tomorrow)

Part Number

Quantity

Company

Contact Name

E-mail

Message