FT25C64A-USR-T EEPROM 64Kbit SPI Memory IC Equivalent & Substitute Parts

Part Overview

The FT25C64A-USR-T is a 64Kbit EEPROM memory IC manufactured by Fremont Micro Devices Ltd, featuring SPI interface operation at 20 MHz with supply voltage range of 1.8V to 5.5V. This non-volatile memory device is classified as Active product status and is RoHS3 compliant. Substitute parts are necessary when the primary part becomes unavailable, when alternative packaging formats are required for manufacturing processes, or when specific operational parameters such as clock frequency or supply voltage ranges need adjustment for system requirements.

Key Parameters

Parameter	Value
Memory Size	64Kbit
Memory Organization	8K x 8
Memory Interface	SPI
Clock Frequency	20 MHz
Write Cycle Time	5ms
Voltage Supply Range	1.8V ~ 5.5V
Operating Temperature	-40°C ~ 85°C
Package Type	8-SOIC (0.154", 3.90mm Width)
Mounting Type	Surface Mount
RoHS Status	ROHS3 Compliant

Substitute Part Grouping Explanation

Substitution eligibility for the FT25C64A-USR-T is determined by strict alignment with the following critical parameters:

Core Compatibility Requirements:

Memory Size: 64Kbit (mandatory)
Memory Organization: 8K x 8 (mandatory)
Memory Interface: SPI (mandatory)
Package Type: 8-SOIC form factor (mandatory)
Voltage Supply Range: Must encompass or match 1.8V ~ 5.5V
Operating Temperature: Must support -40°C ~ 85°C minimum
Write Cycle Time: 5ms or faster

Secondary Consideration Parameters:

Clock Frequency: 20 MHz or higher (backward compatible at lower frequencies)
Mounting Type: Surface Mount (mandatory)
RoHS Compliance: ROHS3 Compliant (mandatory)

Substitute parts are grouped by clock frequency capability and voltage supply specifications. Parts operating at 20 MHz provide direct functional equivalence. Parts rated at lower clock frequencies (10 MHz, 5 MHz, 1 MHz) remain compatible in applications where the system clock does not exceed the part's maximum frequency rating. Parts with narrower voltage supply ranges (2.5V ~ 5.5V) are suitable only for systems operating within that voltage window.

Parameter Comparison

Part Number	Manufacturer	Clock Frequency	Voltage Supply	Write Cycle Time	Operating Temp	Package	Packaging Format	Product Status
FT25C64A-USR-T	Fremont Micro Devices Ltd	20 MHz	1.8V ~ 5.5V	5ms	-40°C ~ 85°C	8-SOIC	Tape & Reel (TR)	Active
25AA640-I/SN	Microchip Technology	1 MHz	1.8V ~ 5.5V	5ms	-40°C ~ 85°C	8-SOIC	Tube	Active
25AA640A-I/SN	Microchip Technology	10 MHz	1.8V ~ 5.5V	5ms	-40°C ~ 85°C	8-SOIC	Tube	Active
25AA640AT-I/SN	Microchip Technology	10 MHz	1.8V ~ 5.5V	5ms	-40°C ~ 85°C	8-SOIC	Cut Tape (CT) & Digi-Reel®	Active
25AA640T-I/SN	Microchip Technology	1 MHz	1.8V ~ 5.5V	5ms	-40°C ~ 85°C	8-SOIC	Cut Tape (CT) & Digi-Reel®	Active
25LC640A-I/SN	Microchip Technology	10 MHz	2.5V ~ 5.5V	5ms	-40°C ~ 85°C	8-SOIC	Tube	Active
AT25640B-SSHL-T	Microchip Technology	20 MHz	1.8V ~ 5.5V	5ms	-40°C ~ 85°C	8-SOIC	Cut Tape (CT) & Digi-Reel®	Active
BR25L640FJ-WE2	Rohm Semiconductor	5 MHz	1.8V ~ 5.5V	5ms	-40°C ~ 85°C	8-SOIC	Tape & Reel (TR)	Active
BR25S640FJ-WE2	Rohm Semiconductor	20 MHz	1.7V ~ 5.5V	5ms	-40°C ~ 85°C	8-SOIC	Tape & Reel (TR)	Active
CAT25640VI-GT3	onsemi	20 MHz	1.8V ~ 5.5V	5ms	-40°C ~ 85°C	8-SOIC	Cut Tape (CT) & Digi-Reel®	Active
M95640-DRMN3TP/K	STMicroelectronics	20 MHz	1.8V ~ 5.5V	4ms	-40°C ~ 125°C	8-SOIC	Cut Tape (CT) & Digi-Reel®	Active

Engineering Selection Recommendations

Direct Equivalents (20 MHz, 1.8V ~ 5.5V Supply):

The AT25640B-SSHL-T, CAT25640VI-GT3, and M95640-DRMN3TP/K provide full functional equivalence to the FT25C64A-USR-T. All three parts maintain identical memory capacity, SPI interface, clock frequency, and voltage supply specifications. The M95640-DRMN3TP/K extends the operating temperature range to -40°C ~ 125°C and includes AEC-Q100 automotive qualification, making it suitable for extended temperature applications. All three maintain RoHS3 compliance and Active product status.

Frequency-Reduced Alternatives (10 MHz, 1.8V ~ 5.5V Supply):

The 25AA640A-I/SN and 25AA640AT-I/SN operate at 10 MHz and are suitable for applications where the system clock does not exceed this frequency. Both maintain the full 1.8V ~ 5.5V supply range and -40°C ~ 85°C operating temperature. The 25AA640AT-I/SN is available in Cut Tape & Digi-Reel® packaging, while 25AA640A-I/SN is supplied in Tube format.

Lower Frequency Alternatives (5 MHz and Below):

The BR25L640FJ-WE2 operates at 5 MHz, and the 25AA640-I/SN and 25AA640T-I/SN operate at 1 MHz. These parts are compatible with systems operating at their respective maximum frequencies or lower. All maintain the 1.8V ~ 5.5V supply range and -40°C ~ 85°C operating temperature.

Voltage-Restricted Alternative:

The 25LC640A-I/SN operates at 10 MHz with a narrower supply voltage range of 2.5V ~ 5.5V. This part is suitable only for systems that do not require operation below 2.5V supply voltage.

Packaging Considerations:

The FT25C64A-USR-T is supplied in Tape & Reel format. Equivalent parts in alternative packaging formats (Cut Tape & Digi-Reel®, Tube) are available from multiple manufacturers and may be selected based on manufacturing process requirements.

Frequently Asked Questions (FAQ)

Q: Can I use a 10 MHz part as a substitute for the 20 MHz FT25C64A-USR-T?

A: Yes, if your system clock does not exceed 10 MHz. The 25AA640A-I/SN and 25AA640AT-I/SN are fully compatible in applications operating at 10 MHz or lower. The memory capacity, organization, interface, voltage supply range, and operating temperature remain identical.

Q: What is the difference between the 25AA640 and 25LC640 series?

A: The primary difference is the minimum supply voltage. The 25AA640 series operates from 1.8V, while the 25LC640A-I/SN operates from 2.5V. Both maintain identical memory specifications and SPI interface. Select 25AA640 for systems requiring operation below 2.5V.

Q: Is the M95640-DRMN3TP/K suitable for automotive applications?

A: Yes. The M95640-DRMN3TP/K carries AEC-Q100 automotive qualification and extends the operating temperature range to -40°C ~ 125°C, making it suitable for automotive and extended temperature industrial applications.

Q: What packaging formats are available for 64Kbit SPI EEPROM substitutes?

A: Substitute parts are available in Tape & Reel (TR), Cut Tape (CT) & Digi-Reel®, and Tube formats. Select based on your manufacturing assembly process requirements. All formats maintain identical electrical specifications.

Q: Can I substitute a part with a faster clock frequency than the original?

A: Yes. A part rated at 20 MHz can operate in applications designed for 20 MHz or lower frequencies. However, a part rated at 10 MHz cannot be used in a 20 MHz application. Always ensure the substitute part's maximum clock frequency meets or exceeds your system requirement.

Q: Are all listed substitutes RoHS3 compliant?

A: Yes. All substitute parts listed maintain RoHS3 compliance and are suitable for applications requiring RoHS certification.

Q: What is the significance of the write cycle time difference between parts?

A: The FT25C64A-USR-T and most substitutes specify 5ms write cycle time. The M95640-DRMN3TP/K specifies 4ms, which is faster. Both are compatible; the faster write cycle time does not create incompatibility issues.

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