93LC66CT-E/ST EEPROM Memory IC Equivalent & Substitute Parts

Part Overview

The 93LC66CT-E/ST is a 4Kbit non-volatile EEPROM memory IC manufactured by Microchip Technology, featuring Microwire serial interface protocol. This component is designed for applications requiring persistent data storage with low power consumption and high reliability across industrial and commercial temperature ranges. The device operates at 3 MHz clock frequency with a 6ms write cycle time and supports supply voltages from 2.5V to 5.5V.

The 93LC66CT-E/ST maintains Active product status and is RoHS3 compliant with unlimited moisture sensitivity rating. Substitute parts are identified based on functional equivalence in memory capacity, interface protocol, package form factor, and electrical operating parameters.

Substiute Parts

93LC66CT-E/ST

Microchip TechnologyIn Stock: 499693LC66CT-E/ST Datasheet

Current PartRFQ

M93C66-RDW3TP/K

STMicroelectronicsIn Stock: 2020M93C66-RDW3TP/K Datasheet

MFR RecommendedRFQ

M93C66-WDW6TP

STMicroelectronicsIn Stock: 105244M93C66-WDW6TP Datasheet

MFR RecommendedRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitute parts for the 93LC66CT-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, ensuring direct functional replacement without firmware modification.

Interface Protocol: All substitutes implement Microwire serial interface, maintaining protocol-level compatibility with existing circuit designs.

Package Form Factor: All substitutes use 8-TSSOP surface mount packaging with identical 0.173" width (4.40mm), enabling direct PCB footprint compatibility.

Supply Voltage Compatibility: Substitute parts operate within overlapping voltage ranges (minimum 1.8V to 2.5V, maximum 5.5V), ensuring compatibility with standard 3.3V and 5V logic systems.

Temperature Range: Substitutes support the industrial temperature range of -40°C to 125°C or -40°C to 85°C, with the latter representing a subset suitable for standard commercial applications.

Clock Frequency: Substitutes operate at 2 MHz, which is lower than the main part's 3 MHz specification but remains compatible with Microwire protocol timing requirements.

Write Cycle Time: Substitutes feature 5ms write cycle time, which is faster than the main part's 6ms specification, providing improved performance characteristics.

Parameter Comparison

Engineering Selection Recommendations

M93C66-RDW3TP/K Selection Criteria: This STMicroelectronics substitute is qualified to AEC-Q100 automotive standard with Automotive grade designation, making it suitable for applications requiring automotive-level reliability and traceability. The extended supply voltage range (1.8V minimum) provides additional flexibility for low-power applications. Operating temperature range matches the main part (-40°C to 125°C). Programmability status is not verified by DiGi-Electronics. Packaging is Tape & Reel format.

M93C66-WDW6TP Selection Criteria: This STMicroelectronics substitute offers the highest inventory availability (105,200 pieces) and is verified as programmable by DiGi-Electronics. Supply voltage range matches the main part (2.5V to 5.5V). Operating temperature range is limited to -40°C to 85°C, suitable for standard commercial and industrial applications within this thermal envelope. Packaging is Cut Tape and Digi-Reel format. This option provides optimal availability and verified programmability for standard applications.

Both substitutes maintain full functional compatibility through identical memory capacity, Microwire interface protocol, and 8-TSSOP package form factor. Selection between substitutes depends on specific application requirements regarding automotive qualification, temperature range, and packaging format preferences.

Frequently Asked Questions (FAQ)

Q: Can M93C66-RDW3TP/K or M93C66-WDW6TP be used as direct replacements for 93LC66CT-E/ST?

A: Yes, both STMicroelectronics parts are functionally equivalent substitutes. They maintain identical 4Kbit memory capacity, 512 x 8 / 256 x 16 organization, Microwire serial interface, and 8-TSSOP surface mount package. Circuit-level compatibility is assured for standard applications operating within the overlapping supply voltage range (2.5V to 5.5V) and temperature specifications of the selected substitute.

Q: What is the difference in clock frequency between the main part and substitutes?

A: The 93LC66CT-E/ST operates at 3 MHz maximum clock frequency, while both M93C66 substitutes operate at 2 MHz. The lower frequency of substitute parts does not prevent compatibility; Microwire protocol timing remains valid at 2 MHz operation. Applications designed for 3 MHz operation will function correctly with 2 MHz substitutes, though data transfer rates will be proportionally reduced.

Q: Are there temperature range limitations when selecting a substitute?

A: The M93C66-RDW3TP/K maintains the full industrial temperature range (-40°C to 125°C) matching the main part. The M93C66-WDW6TP is limited to -40°C to 85°C, which covers standard commercial and industrial applications but excludes high-temperature environments above 85°C. Select M93C66-RDW3TP/K for applications requiring operation above 85°C.

Q: What is the significance of the AEC-Q100 qualification on M93C66-RDW3TP/K?

A: AEC-Q100 qualification indicates the part meets automotive industry reliability and quality standards. This certification is relevant only for automotive applications or systems requiring automotive-grade component traceability. For non-automotive applications, this qualification provides no functional advantage.

Q: How do write cycle times affect system performance?

A: The main part specifies 6ms write cycle time, while both substitutes specify 5ms. The faster write cycle of substitutes represents improved performance and does not create compatibility issues. Systems designed for 6ms write timing will operate correctly with 5ms write cycle parts.

Q: Are all three parts RoHS3 compliant?

A: Yes, the 93LC66CT-E/ST, M93C66-RDW3TP/K, and M93C66-WDW6TP are all RoHS3 compliant with unlimited moisture sensitivity rating (MSL 1), meeting environmental and regulatory requirements for commercial and industrial applications.

Q: What packaging format differences exist between substitutes?

A: The 93LC66CT-E/ST uses standard 8-TSSOP surface mount package. M93C66-RDW3TP/K is supplied in Tape & Reel format for automated assembly. M93C66-WDW6TP is supplied in Cut Tape and Digi-Reel format. All three maintain identical 8-TSSOP footprint compatibility; packaging format differences relate only to supply and handling methods, not PCB integration.