25LC040AX-E/ST EEPROM Memory IC Equivalent & Substitute Parts

Part Overview

The 25LC040AX-E/ST is a 4Kbit Serial Peripheral Interface (SPI) EEPROM memory IC manufactured by Microchip Technology. This non-volatile memory device operates at 10 MHz clock frequency with a supply voltage range of 2.5V to 5.5V and is housed in an 8-TSSOP surface mount package. The part is currently active in production with RoHS3 compliance and unlimited moisture sensitivity rating (MSL 1).

Substitute parts are necessary when the original part number becomes unavailable, when alternative packaging formats are required for manufacturing processes, or when enhanced performance specifications (such as higher clock frequency or extended temperature ranges) are needed for specific applications.

Substiute Parts

25LC040AX-E/ST

Microchip TechnologyIn Stock: 69325LC040AX-E/ST Datasheet

Current PartRFQ

AT25040B-XHL-B

Microchip TechnologyIn Stock: 2863AT25040B-XHL-B Datasheet

MFR RecommendedRFQ

AT25040B-XHL-T

Microchip TechnologyIn Stock: 18688AT25040B-XHL-T Datasheet

MFR RecommendedRFQ

M95040-DRDW3TP/K

STMicroelectronicsIn Stock: 18961M95040-DRDW3TP/K Datasheet

MFR RecommendedRFQ

M95040-DRDW8TP/K

STMicroelectronicsIn Stock: 4569M95040-DRDW8TP/K Datasheet

MFR RecommendedRFQ

M95040-RDW6TP

STMicroelectronicsIn Stock: 16047M95040-RDW6TP Datasheet

MFR RecommendedRFQ

M95040-WDW6TP

STMicroelectronicsIn Stock: 1544M95040-WDW6TP Datasheet

MFR RecommendedRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution eligibility for the 25LC040AX-E/ST is determined by the following critical parameters:

Core Compatibility Requirements:

• Memory Size: 4Kbit (512 x 8 organization)
• Memory Interface: SPI
• Package / Case: 8-TSSOP (0.173", 4.40mm Width)
• Mounting Type: Surface Mount
• Memory Format: EEPROM

Performance Parameters (Allowable Variations):

• Clock Frequency: 10 MHz or higher
• Write Cycle Time: 5ms or faster
• Supply Voltage Range: Must encompass 2.5V ~ 5.5V or be compatible with this range
• Operating Temperature: Must support -40°C minimum and 125°C maximum, or narrower ranges within these limits

Compliance Parameters:

• RoHS3 Compliance required
• REACH Unaffected status required
• Part Status: Active

Substitute parts may differ in packaging format (Tube, Tape & Reel, Cut Tape & Digi-Reel), manufacturer, MSL rating, and automotive qualification status, provided the core compatibility and performance requirements are met.

Parameter Comparison

Engineering Selection Recommendations

Direct Substitutes (Highest Compatibility):

M95040-DRDW3TP/K and M95040-DRDW8TP/K are the most suitable substitutes for the 25LC040AX-E/ST. Both parts maintain MSL 1 (Unlimited) rating, support the full operating temperature range of -40°C to 125°C (or 105°C), and offer improved performance with 20 MHz clock frequency and faster write cycle times (4ms). M95040-DRDW3TP/K is available in Cut Tape & Digi-Reel format, while M95040-DRDW8TP/K is supplied in Tape & Reel format. Both are AEC-Q100 qualified automotive-grade components manufactured by STMicroelectronics.

Alternative Substitutes (Conditional Compatibility):

AT25040B-XHL-B and AT25040B-XHL-T provide equivalent 4Kbit SPI EEPROM functionality with doubled clock frequency (20 MHz). These Microchip Technology parts are available in Tube and Tape & Reel packaging respectively. However, both parts have MSL 3 (168 Hours) rating and operate within a narrower temperature range (-40°C to 85°C), which may not satisfy applications requiring the full 125°C upper temperature limit of the original part.

M95040-RDW6TP and M95040-WDW6TP are STMicroelectronics alternatives with 20 MHz clock frequency and MSL 1 rating. M95040-RDW6TP operates to 85°C, while M95040-WDW6TP maintains the original 2.5V to 5.5V supply voltage range. Both are suitable for applications where the narrower temperature range is acceptable.

Selection Criteria:

• For applications requiring full -40°C to 125°C temperature range: Select M95040-DRDW3TP/K or M95040-DRDW8TP/K
• For applications with -40°C to 85°C temperature requirement: Select AT25040B-XHL-B, AT25040B-XHL-T, M95040-RDW6TP, or M95040-WDW6TP
• For automotive applications: Select M95040-DRDW3TP/K or M95040-DRDW8TP/K (AEC-Q100 qualified)
• For tape and reel assembly processes: Select AT25040B-XHL-T, M95040-DRDW8TP/K, or M95040-WDW6TP
• For cut tape and digi-reel processes: Select M95040-DRDW3TP/K or M95040-RDW6TP

All substitute parts maintain RoHS3 compliance and REACH Unaffected status consistent with the original part.

Frequently Asked Questions (FAQ)

Q: Can I use AT25040B-XHL-B as a direct replacement for 25LC040AX-E/ST in all applications?

A: AT25040B-XHL-B is functionally compatible for SPI EEPROM applications requiring 4Kbit storage in 8-TSSOP packaging. However, it has two limitations: MSL 3 (168 Hours) rating versus MSL 1 (Unlimited) on the original part, and operating temperature range of -40°C to 85°C versus -40°C to 125°C. Use this substitute only if your application operates within the 85°C maximum temperature and your manufacturing process accommodates the MSL 3 moisture sensitivity requirement.

Q: What is the difference between M95040-DRDW3TP/K and M95040-DRDW8TP/K?

A: Both parts are STMicroelectronics M95040 4Kbit SPI EEPROM devices with identical electrical specifications (20 MHz clock, 4ms write cycle, 1.8V ~ 5.5V supply, MSL 1 rating, AEC-Q100 qualification). The primary difference is packaging format: M95040-DRDW3TP/K is supplied in Cut Tape & Digi-Reel format, while M95040-DRDW8TP/K is supplied in Tape & Reel format. M95040-DRDW8TP/K also supports a slightly narrower operating temperature range (-40°C to 105°C) compared to M95040-DRDW3TP/K (-40°C to 125°C).

Q: Why does M95040-WDW6TP have a different supply voltage range than other M95040 variants?

A: M95040-WDW6TP is specified with 2.5V ~ 5.5V supply voltage range, matching the original 25LC040AX-E/ST part. Other M95040 variants (DRDW3TP/K, DRDW8TP/K, RDW6TP) support extended low-voltage operation down to 1.8V. Select M95040-WDW6TP if your application requires the 2.5V minimum supply voltage specification.

Q: Are all substitute parts RoHS3 compliant?

A: Yes. All substitute parts listed (AT25040B-XHL-B, AT25040B-XHL-T, M95040-DRDW3TP/K, M95040-DRDW8TP/K, M95040-RDW6TP, M95040-WDW6TP) are RoHS3 compliant and REACH Unaffected, consistent with the original 25LC040AX-E/ST part.

Q: Can I use these substitutes in automotive applications?

A: M95040-DRDW3TP/K and M95040-DRDW8TP/K are AEC-Q100 qualified automotive-grade components and are suitable for automotive applications. The Microchip AT25040B variants and STMicroelectronics M95040-RDW6TP and M95040-WDW6TP are not specified with automotive qualification in the provided data and should not be assumed suitable for automotive use without additional verification.

Q: What is the significance of MSL rating differences?

A: MSL (Moisture Sensitivity Level) rating indicates the maximum time a component can be exposed to moisture before soldering. MSL 1 (Unlimited) means the part has no time restriction and can be stored indefinitely in normal conditions. MSL 3 (168 Hours) means the part must be soldered within 168 hours of exposure to moisture. If your manufacturing process involves extended storage or high-humidity environments, select parts with MSL 1 rating (25LC040AX-E/ST, M95040-DRDW3TP/K, M95040-DRDW8TP/K, M95040-RDW6TP, M95040-WDW6TP).

Q: Is the 20 MHz clock frequency of substitute parts backward compatible with 10 MHz designs?

A: Yes. All substitute parts with 20 MHz clock frequency are backward compatible with designs using 10 MHz operation. The SPI interface allows clock frequency to be set lower than the maximum rated frequency. However, verify that your system firmware or hardware configuration supports the selected substitute part's other specifications (voltage range, temperature range, write cycle time).