93AA66C-I/ST EEPROM Memory IC Equivalent & Substitute Parts

Part Overview

The 93AA66C-I/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 wide voltage operation range. The part is currently in active production status with RoHS3 compliance and unlimited moisture sensitivity rating. Substitute parts are identified when equivalent memory capacity, compatible serial interface protocols, matching package form factors, and overlapping voltage specifications are maintained across the component lifecycle and supply chain variations.

Substiute Parts

93AA66C-I/ST

Microchip TechnologyIn Stock: 103593AA66C-I/ST Datasheet

Current PartRFQ

AT93C66B-XHM-B

Microchip TechnologyIn Stock: 3124AT93C66B-XHM-B Datasheet

MFR RecommendedRFQ

M93C66-RDW3TP/K

STMicroelectronicsIn Stock: 2020M93C66-RDW3TP/K Datasheet

MFR RecommendedRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution eligibility for the 93AA66C-I/ST is determined by the following critical parameters:

Memory Capacity & Organization: All substitute parts must maintain 4Kbit capacity with 512 x 8 or 256 x 16 organization to ensure data structure compatibility.

Serial Interface Protocol: The 93AA66C-I/ST uses Microwire protocol. Substitutes using alternative serial protocols (such as 3-Wire Serial) require protocol-level compatibility verification at the system design level and are listed as cross-protocol alternatives.

Package Form Factor: All candidates must use 8-TSSOP surface mount packaging (0.173", 4.40mm width) to maintain PCB layout compatibility.

Voltage Supply Range: Substitute parts must support the minimum 1.8V lower bound and 5.5V upper bound of the primary part, or operate within a subset of this range if the application voltage is constrained.

Operating Temperature Range: The primary part operates -40°C to 85°C. Substitutes with extended temperature ranges (such as -40°C to 125°C) are compatible for standard applications and provide additional margin for harsh environments.

Compliance & Status: All parts must maintain active production status and RoHS3 compliance for new design qualification.

Parameter Comparison

Engineering Selection Recommendations

Direct Microwire Protocol Substitute: The M93C66-RDW3TP/K from STMicroelectronics maintains identical Microwire serial interface protocol as the primary part. This substitute is suitable for applications requiring protocol-level compatibility without firmware modification. The extended operating temperature range (-40°C to 125°C) and AEC-Q100 automotive qualification provide additional environmental margin. Clock frequency is reduced from 3 MHz to 2 MHz; this does not impact functionality in standard applications but should be verified if timing-critical operations depend on maximum clock speed.

Cross-Protocol Alternative: The AT93C66B-XHM-B from Microchip Technology uses 3-Wire Serial protocol instead of Microwire. This part is electrically compatible in terms of memory capacity, package, and voltage specifications, but requires protocol-level compatibility assessment at the system design level. Selection of this part is appropriate only when the application firmware or hardware interface supports 3-Wire Serial protocol or when protocol conversion is implemented.

Supply Chain & Packaging Considerations: The primary part is supplied in Tube packaging, while the M93C66-RDW3TP/K is supplied in Tape & Reel format. Both formats are suitable for production environments; Tape & Reel is standard for automated assembly processes. The AT93C66B-XHM-B maintains Tube packaging consistency with the primary part.

Compliance & Production Status: All three parts maintain active production status and ROHS3 compliance, ensuring long-term availability and regulatory alignment for new designs.

Frequently Asked Questions (FAQ)

Q: Can the AT93C66B-XHM-B replace the 93AA66C-I/ST directly without firmware changes?

A: The AT93C66B-XHM-B uses 3-Wire Serial protocol while the primary part uses Microwire protocol. Direct replacement requires that the application firmware and hardware interface support 3-Wire Serial communication. If the system is designed exclusively for Microwire protocol, firmware and interface modifications are necessary.

Q: What is the impact of reduced clock frequency in the M93C66-RDW3TP/K?

A: The M93C66-RDW3TP/K operates at 2 MHz compared to the primary part's 3 MHz. This reduction does not affect memory capacity, data retention, or write cycle time. Applications with timing-critical serial communication loops should verify that 2 MHz clock speed meets system requirements.

Q: Are all three parts suitable for automotive applications?

A: The M93C66-RDW3TP/K carries AEC-Q100 automotive qualification. The 93AA66C-I/ST and AT93C66B-XHM-B are standard industrial-grade parts. For automotive applications, the M93C66-RDW3TP/K is the qualified choice.

Q: What is the difference between Tube and Tape & Reel packaging?

A: Tube packaging is suitable for manual handling and small-volume assembly. Tape & Reel packaging is optimized for automated pick-and-place assembly in high-volume production. Both formats contain identical components; packaging selection depends on manufacturing process requirements.

Q: Can I use the extended temperature range of the M93C66-RDW3TP/K in standard applications?

A: Yes. The extended operating range (-40°C to 125°C) is a superset of the primary part's range (-40°C to 85°C). The M93C66-RDW3TP/K is fully compatible with applications designed for the primary part's temperature specifications and provides additional margin for harsh environment exposure.

Q: Are voltage supply ranges compatible across all three parts?

A: The 93AA66C-I/ST and M93C66-RDW3TP/K both support 1.8V to 5.5V. The AT93C66B-XHM-B supports 1.7V to 5.5V, providing slightly lower minimum voltage operation. All three parts are compatible with standard 3.3V and 5V supply systems.