FT24C64A-USR-T Equivalent & Substitute Parts

Part Overview

The FT24C64A-USR-T is a 64Kbit EEPROM memory IC with I2C interface manufactured by Fremont Micro Devices Ltd. This part operates at 800 kHz clock frequency with 700 ns access time, supporting supply voltages from 1.8V to 5.5V across the industrial temperature range of -40°C to 85°C. The device is packaged in 8-SOIC (0.154", 3.90mm width) surface mount configuration and is ROHS3 compliant.

The FT24C64A-USR-T has been discontinued at DiGi Electronics. Direct substitutes and functionally equivalent alternatives are available from both the same manufacturer and alternative suppliers to maintain design continuity and ensure component availability for production and maintenance applications.

Key Parameters

Parameter	Value
Memory Size	64Kbit
Memory Organization	8K x 8
Memory Interface	I2C
Clock Frequency	800 kHz
Access Time	700 ns
Write Cycle Time	5ms
Voltage Supply Range	1.8V ~ 5.5V
Operating Temperature	-40°C ~ 85°C
Package / Case	8-SOIC (0.154", 3.90mm Width)
Mounting Type	Surface Mount
RoHS Status	ROHS3 Compliant
Moisture Sensitivity Level	1 (Unlimited)

Substitute Part Grouping Explanation

Substitution eligibility for the FT24C64A-USR-T is determined by strict adherence to the following parameters:

Critical Parameters (Must Match):

Memory Size: 64Kbit
Memory Organization: 8K x 8
Memory Interface: I2C
Package / Case: 8-SOIC (0.154", 3.90mm Width)
Mounting Type: Surface Mount

Compatible Parameter Ranges (May Vary):

Clock Frequency: 800 kHz or higher (backward compatible)
Access Time: 700 ns or faster (backward compatible)
Voltage Supply Range: Must encompass 1.8V ~ 5.5V or be a subset within this range
Operating Temperature: Must support at least -40°C ~ 85°C
Write Cycle Time: 5ms or faster (backward compatible)

Substitute parts are grouped into two categories:

Direct Manufacturer Substitutes: Parts from Fremont Micro Devices Ltd with identical electrical specifications and package, differing only in product status or packaging format.

Functionally Equivalent Alternatives: Parts from Microchip Technology with identical memory capacity, organization, and interface, but with different performance characteristics (clock frequency, access time) or temperature ratings. These parts are electrically compatible and pin-compatible within the 8-SOIC package.

Parameter Comparison

Part Number	Manufacturer	Memory Size	Clock Frequency	Access Time	Voltage Supply	Operating Temperature	Package	Product Status
FT24C64A-USR-T	Fremont Micro Devices Ltd	64Kbit	800 kHz	700 ns	1.8V ~ 5.5V	-40°C ~ 85°C	8-SOIC	Discontinued
FT24C64A-USG-T	Fremont Micro Devices Ltd	64Kbit	800 kHz	700 ns	1.8V ~ 5.5V	-40°C ~ 85°C	8-SOIC	Active
24AA64-E/SN	Microchip Technology	64Kbit	400 kHz	900 ns	1.7V ~ 5.5V	-40°C ~ 125°C	8-SOIC	Active
24AA64F-I/SN	Microchip Technology	64Kbit	400 kHz	900 ns	1.7V ~ 5.5V	-40°C ~ 85°C	8-SOIC	Active
24AA64FT-I/SN	Microchip Technology	64Kbit	400 kHz	900 ns	1.7V ~ 5.5V	-40°C ~ 85°C	8-SOIC	Active
24AA64T-E/SN	Microchip Technology	64Kbit	400 kHz	900 ns	1.7V ~ 5.5V	-40°C ~ 125°C	8-SOIC	Active
24AA64T-I/SN	Microchip Technology	64Kbit	400 kHz	900 ns	1.7V ~ 5.5V	-40°C ~ 85°C	8-SOIC	Active
24AA64T-I/SNG	Microchip Technology	64Kbit	400 kHz	900 ns	1.7V ~ 5.5V	-40°C ~ 85°C	8-SOIC	Active
24FC64-I/SN	Microchip Technology	64Kbit	1 MHz	400 ns	1.7V ~ 5.5V	-40°C ~ 85°C	8-SOIC	Active
24FC64F-I/SN	Microchip Technology	64Kbit	1 MHz	400 ns	1.7V ~ 5.5V	-40°C ~ 85°C	8-SOIC	Active
24FC64FT-I/SN	Microchip Technology	64Kbit	1 MHz	400 ns	1.7V ~ 5.5V	-40°C ~ 85°C	8-SOIC	Active

Engineering Selection Recommendations

Primary Recommendation: FT24C64A-USG-T

The FT24C64A-USG-T is the direct substitute for the discontinued FT24C64A-USR-T. Both parts are manufactured by Fremont Micro Devices Ltd with identical electrical specifications, memory organization, and package configuration. The FT24C64A-USG-T is currently in active production status with 1037 units in stock. This part requires no design modifications and maintains full compatibility with existing PCB layouts and firmware implementations. Both parts are ROHS3 compliant with MSL rating of 1 (Unlimited).

Secondary Recommendation: Microchip Technology 24AA64 Series

The Microchip 24AA64-E/SN, 24AA64F-I/SN, 24AA64FT-I/SN, 24AA64T-E/SN, 24AA64T-I/SN, and 24AA64T-I/SNG are functionally equivalent alternatives. These parts maintain the same 64Kbit capacity, 8K x 8 organization, and I2C interface within the 8-SOIC package. The 24AA64 series operates at 400 kHz clock frequency with 900 ns access time, which is slower than the FT24C64A-USR-T but remains fully compatible for I2C bus operation. All variants are in active production with substantial inventory availability. These parts are ROHS3 compliant.

Tertiary Recommendation: Microchip Technology 24FC64 Series

The Microchip 24FC64-I/SN, 24FC64F-I/SN, and 24FC64FT-I/SN offer enhanced performance with 1 MHz clock frequency and 400 ns access time. These parts exceed the performance specifications of the FT24C64A-USR-T while maintaining full I2C compatibility and 8-SOIC packaging. The 24FC64 series is suitable for applications requiring faster data access. All variants are in active production and ROHS3 compliant.

All recommended substitutes support the voltage supply range of 1.8V to 5.5V and operate across the industrial temperature range of -40°C to 85°C, ensuring compatibility with the original design specifications.

Frequently Asked Questions (FAQ)

Q: Can I directly replace FT24C64A-USR-T with FT24C64A-USG-T without any modifications?

A: Yes. Both parts are manufactured by Fremont Micro Devices Ltd with identical electrical specifications, memory capacity, clock frequency, access time, voltage supply range, operating temperature range, and 8-SOIC package configuration. No PCB layout changes or firmware modifications are required.

Q: What is the difference between the FT24C64A-USR-T and the Microchip 24AA64 series?

A: The primary difference is clock frequency and access time. The FT24C64A-USR-T operates at 800 kHz with 700 ns access time, while the 24AA64 series operates at 400 kHz with 900 ns access time. Both are I2C compatible and pin-compatible in the 8-SOIC package. The 24AA64 series is slower but fully functional for standard I2C applications. The 24AA64 series also supports an extended temperature range up to 125°C on select variants.

Q: Can I use the faster Microchip 24FC64 series as a substitute?

A: Yes. The 24FC64 series operates at 1 MHz with 400 ns access time, exceeding the performance of the FT24C64A-USR-T. These parts are pin-compatible in the 8-SOIC package and fully compatible with I2C bus operation. The faster performance makes them suitable for applications requiring higher data throughput.

Q: Are all substitute parts ROHS3 compliant?

A: Yes. The FT24C64A-USG-T and all Microchip alternatives (24AA64 and 24FC64 series) are ROHS3 compliant, matching the compliance status of the original FT24C64A-USR-T.

Q: What is the difference between packaging options like Tube, Tape & Reel, and Cut Tape?

A: Packaging format affects order quantity and handling. Tube packaging is typically for smaller quantities. Tape & Reel (TR) is standard for automated assembly lines. Cut Tape (CT) & Digi-Reel® provides flexibility for mixed quantities. All packaging formats contain electrically identical parts; the choice depends on manufacturing process requirements and order volume.

Q: Does the voltage supply range difference between 1.8V ~ 5.5V and 1.7V ~ 5.5V affect compatibility?

A: The Microchip alternatives support 1.7V minimum, which is lower than the FT24C64A-USR-T specification of 1.8V. For applications operating at 1.8V or higher, both specifications are compatible. For applications requiring operation below 1.8V, the Microchip parts provide additional margin. The upper limit of 5.5V is identical across all parts.

Q: What is the Moisture Sensitivity Level (MSL) and why does it matter?

A: MSL indicates the maximum time a component can be exposed to moisture before soldering. MSL 1 (Unlimited) means no time restriction. MSL 3 (168 Hours) means the component must be soldered within 168 hours of opening the package. The FT24C64A-USR-T and most alternatives have MSL 1, providing maximum handling flexibility. Some Microchip variants have MSL 3, requiring adherence to moisture control procedures.

Q: Are there any firmware or software changes needed when switching to a substitute part?

A: No. All substitute parts maintain I2C protocol compatibility and identical memory organization (8K x 8). Firmware and software require no modifications. The I2C bus will automatically operate at the speed supported by the slowest device on the bus, ensuring transparent operation.

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