93C66AT-I/ST EEPROM Memory IC Equivalent & Substitute Parts

Part Overview

The 93C66AT-I/ST is a 4Kbit EEPROM memory integrated circuit manufactured by Microchip Technology, designed for non-volatile data storage applications requiring Microwire serial interface communication. This device operates at 2 MHz clock frequency with a supply voltage range of 4.5V to 5.5V and is housed in an 8-TSSOP surface mount package. The part maintains active product status and is ROHS3 compliant. Substitute parts are identified when equivalent memory capacity, interface protocol, package form factor, and operating specifications align within acceptable electrical and mechanical tolerances.

Substiute Parts

93C66AT-I/ST

Microchip TechnologyIn Stock: 80093C66AT-I/ST Datasheet

Current PartRFQ

93LC66A-I/ST

Microchip TechnologyIn Stock: 225693LC66A-I/ST Datasheet

MFR RecommendedRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution eligibility for the 93C66AT-I/ST is determined by the following critical parameters:

Memory Capacity & Organization: The substitute part must provide 4Kbit storage capacity with 512 x 8 bit organization to maintain functional equivalence in data storage applications.

Serial Interface Protocol: The Microwire interface is mandatory for communication compatibility with existing circuit designs and firmware implementations.

Package Compatibility: The 8-TSSOP surface mount package with 0.173" width (4.40mm) ensures mechanical and electrical compatibility with PCB layouts designed for the original part.

Operating Temperature Range: The -40°C to 85°C operating range must be maintained to ensure reliable operation across specified environmental conditions.

Supply Voltage Compatibility: While the main part operates at 4.5V to 5.5V, substitute parts with extended voltage ranges (such as 2.5V to 5.5V) remain compatible when used within the original part's voltage specification window.

The 93LC66A-I/ST meets all substitution criteria and is identified as the manufacturer-recommended equivalent.

Parameter Comparison

Engineering Selection Recommendations

Both the 93C66AT-I/ST and 93LC66A-I/ST maintain active product status from Microchip Technology and satisfy ROHS3 and REACH compliance requirements. The 93LC66A-I/ST is designated as the manufacturer-recommended substitute and carries verified programmability status. Selection between these parts should be based on application-specific requirements regarding write cycle timing and supply voltage operating range. The 93LC66A-I/ST provides extended lower voltage operation (2.5V minimum) compared to the main part (4.5V minimum), making it suitable for low-power applications. The extended write cycle time of 6ms versus 2ms for the main part must be evaluated against application timing constraints.

Frequently Asked Questions (FAQ)

Q: Can the 93LC66A-I/ST be used as a direct replacement for the 93C66AT-I/ST?

A: Yes. Both parts share identical memory capacity (4Kbit), organization (512 x 8), Microwire interface, clock frequency (2 MHz), package form factor (8-TSSOP), and operating temperature range (-40°C to 85°C). The 93LC66A-I/ST is the manufacturer-recommended equivalent.

Q: What is the difference in write cycle time between these parts?

A: The 93C66AT-I/ST has a write cycle time of 2ms, while the 93LC66A-I/ST has a write cycle time of 6ms. Applications requiring faster write operations should retain the original part specification.

Q: Does the extended voltage range of the 93LC66A-I/ST affect compatibility?

A: No. The 93LC66A-I/ST operates across 2.5V to 5.5V, which encompasses the original part's 4.5V to 5.5V range. When used in circuits designed for 4.5V to 5.5V operation, the substitute part functions identically.

Q: Are the packaging and pinout identical?

A: Yes. Both parts use the 8-TSSOP surface mount package with 0.173" width (4.40mm). Pinout and mechanical dimensions are identical, allowing direct PCB substitution without layout modifications.

Q: What compliance certifications apply to both parts?

A: Both the 93C66AT-I/ST and 93LC66A-I/ST are ROHS3 compliant, REACH unaffected, and carry Moisture Sensitivity Level 1 (unlimited). Both maintain active product status.