FT93C46A-ISR-T Equivalent & Substitute Parts

Part Overview

The FT93C46A-ISR-T is a 1Kbit EEPROM memory IC with 3-Wire Serial interface operating at 2 MHz, manufactured by Fremont Micro Devices Ltd in 8-SOP surface mount packaging. This part is discontinued at DiGi Electronics, necessitating identification of functionally equivalent alternatives. Substitute parts must maintain compatibility across memory capacity, interface protocol, package form factor, and electrical operating ranges to ensure direct replacement capability in existing designs.

Key Parameters

Parameter	FT93C46A-ISR-T
Memory Size	1Kbit
Memory Organization	128 x 8, 64 x 16
Memory Interface	3-Wire Serial
Clock Frequency	2 MHz
Voltage Supply Range	1.8V ~ 5.5V
Operating Temperature	-40°C ~ 85°C
Write Cycle Time	10ms
Package / Case	8-SOIC (0.154", 3.90mm Width)
Mounting Type	Surface Mount
RoHS Status	ROHS3 Compliant

Substitute Part Grouping Explanation

Substitution eligibility is determined by the following criteria:

Direct Substitutes maintain identical memory capacity (1Kbit), memory organization (128 x 8, 64 x 16), interface protocol (3-Wire Serial), package form factor (8-SOIC), and mounting type (Surface Mount). Clock frequency may vary within application tolerance. Voltage supply range and operating temperature must encompass or match the original specification.

Compatible Alternatives share the same memory capacity, organization, and package but employ Microwire interface protocol instead of 3-Wire Serial. Microwire is functionally equivalent for 1Kbit EEPROM applications with compatible pinout mapping. These parts operate at higher clock frequencies (3 MHz) and may have different voltage or temperature ranges.

Key Parameters for Substitution:

Memory Size: 1Kbit (mandatory)
Memory Organization: 128 x 8, 64 x 16 (mandatory)
Package / Case: 8-SOIC (mandatory)
Interface Protocol: 3-Wire Serial or Microwire (functionally compatible)
Mounting Type: Surface Mount (mandatory)

Parameter Comparison

Part Number	Manufacturer	Memory Size	Interface	Clock Frequency	Voltage Supply	Operating Temperature	Write Cycle Time	Package	Product Status
FT93C46A-ISR-T	Fremont Micro Devices Ltd	1Kbit	3-Wire Serial	2 MHz	1.8V ~ 5.5V	-40°C ~ 85°C	10ms	8-SOIC	Discontinued
FT93C46A-USR-T	Fremont Micro Devices Ltd	1Kbit	3-Wire Serial	1 MHz	4.5V ~ 5.5V	-40°C ~ 85°C	10ms	8-SOIC	Active
93AA46CX-I/SN	Microchip Technology	1Kbit	Microwire	3 MHz	1.8V ~ 5.5V	-40°C ~ 85°C	6ms	8-SOIC	Active
93AA46CXT-I/SN	Microchip Technology	1Kbit	Microwire	3 MHz	1.8V ~ 5.5V	-40°C ~ 85°C	6ms	8-SOIC	Active
93LC46CX-E/SN	Microchip Technology	1Kbit	Microwire	3 MHz	2.5V ~ 5.5V	-40°C ~ 125°C	6ms	8-SOIC	Active
93LC46CX-I/SN	Microchip Technology	1Kbit	Microwire	3 MHz	2.5V ~ 5.5V	-40°C ~ 85°C	6ms	8-SOIC	Active
93LC46CXT-E/SN	Microchip Technology	1Kbit	Microwire	3 MHz	2.5V ~ 5.5V	-40°C ~ 125°C	6ms	8-SOIC	Active
93LC46CXT-I/SN	Microchip Technology	1Kbit	Microwire	3 MHz	2.5V ~ 5.5V	-40°C ~ 85°C	6ms	8-SOIC	Active

Engineering Selection Recommendations

Primary Recommendation: FT93C46A-USR-T

The FT93C46A-USR-T is the direct equivalent from the same manufacturer (Fremont Micro Devices Ltd) with identical 3-Wire Serial interface and 8-SOIC package. This part maintains full protocol compatibility and is currently in active production status. The reduced clock frequency (1 MHz versus 2 MHz) does not impact functionality in applications where the original 2 MHz specification was not a critical design requirement. Voltage supply range is narrower (4.5V ~ 5.5V), requiring verification that system supply voltages remain within this window. Write cycle time and operating temperature range are identical to the original part.

Secondary Recommendations: Microchip 93AA46 and 93LC46 Series

The Microchip 93AA46CX-I/SN and 93AA46CXT-I/SN parts provide full functional equivalence with Microwire interface protocol and identical voltage supply range (1.8V ~ 5.5V) to the original FT93C46A-ISR-T. These parts are actively produced and ROHS3 compliant. The Microwire protocol is functionally compatible with 3-Wire Serial for 1Kbit EEPROM applications. Higher clock frequency (3 MHz) and faster write cycle time (6ms) provide performance improvement.

The Microchip 93LC46 series (93LC46CX-E/SN, 93LC46CX-I/SN, 93LC46CXT-E/SN, 93LC46CXT-I/SN) extends operating temperature to -40°C ~ 125°C and reduces minimum supply voltage to 2.5V, offering enhanced environmental performance. These parts are suitable for applications requiring extended temperature operation.

All recommended substitutes are ROHS3 compliant and REACH unaffected, matching the original part's regulatory status.

Frequently Asked Questions (FAQ)

Q: Can FT93C46A-USR-T directly replace FT93C46A-ISR-T in all applications?

A: Yes, with one consideration. The FT93C46A-USR-T maintains identical interface protocol (3-Wire Serial), memory capacity, organization, package, and operating temperature range. The voltage supply range is narrower (4.5V ~ 5.5V versus 1.8V ~ 5.5V). Verify that your system supply voltage remains within 4.5V ~ 5.5V. The reduced clock frequency (1 MHz) is functionally compatible unless your application specifically requires 2 MHz operation.

Q: What is the difference between 3-Wire Serial and Microwire interfaces?

A: Both protocols are serial communication standards for EEPROM devices with compatible pinout mapping for 1Kbit memory ICs in 8-SOIC packages. Microwire is functionally equivalent for read/write operations in this memory class. Microchip's 93AA46 and 93LC46 series employ Microwire protocol and are direct functional replacements for 3-Wire Serial devices in this application category.

Q: Why do some substitutes have faster write cycle times (6ms versus 10ms)?

A: The Microchip alternatives (93AA46 and 93LC46 series) feature optimized write cycle timing of 6ms compared to the original 10ms specification. This represents improved performance and does not affect compatibility. Applications designed for 10ms write cycles will function correctly with 6ms write cycle devices.

Q: Are all recommended substitutes available in both Tube and Tape & Reel packaging?

A: The Microchip 93AA46 and 93LC46 series are available in both Tube and Tape & Reel (TR) packaging options. Select packaging based on your procurement and assembly requirements. Both packaging formats contain identical die and electrical specifications.

Q: Which substitute should I select for extended temperature applications?

A: The Microchip 93LC46CX-E/SN and 93LC46CXT-E/SN parts operate across -40°C ~ 125°C, extending the upper temperature limit from 85°C to 125°C. These parts are suitable for industrial and automotive applications requiring enhanced thermal performance.

Q: Are all substitutes ROHS3 compliant?

A: Yes. All recommended substitutes (FT93C46A-USR-T, 93AA46CX-I/SN, 93AA46CXT-I/SN, 93LC46CX-E/SN, 93LC46CX-I/SN, 93LC46CXT-E/SN, 93LC46CXT-I/SN) are ROHS3 compliant and REACH unaffected, matching the regulatory status of the original FT93C46A-ISR-T.

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