Equivalent & Substitute Parts for 25LC040AT-E/SN

Part Overview

The 25LC040AT-E/SN is a 4Kbit EEPROM memory IC manufactured by Microchip Technology, featuring SPI interface operation at 10 MHz with 8-SOIC surface mount packaging. This device operates across a supply voltage range of 2.5V to 5.5V and supports operating temperatures from -40°C to 125°C. The part is currently in active production status with ROHS3 compliance and unlimited moisture sensitivity rating.

Equivalent and substitute parts are identified based on matching core electrical parameters: memory capacity (4Kbit), memory organization (512 x 8), interface protocol (SPI), package type (8-SOIC or compatible variants), voltage supply range compatibility, and operating temperature specifications. Substitutes may vary in clock frequency, write cycle time, and specific package dimensions while maintaining functional equivalence for standard applications.

Key Parameters

Parameter	Value
Memory Size	4Kbit
Memory Organization	512 x 8
Memory Interface	SPI
Clock Frequency	10 MHz
Voltage Supply Range	2.5V ~ 5.5V
Operating Temperature	-40°C ~ 125°C
Write Cycle Time	5ms
Package Type	8-SOIC (0.154", 3.90mm Width)
Mounting Type	Surface Mount
RoHS Status	ROHS3 Compliant

Substitute Part Grouping Explanation

Substitute parts are grouped into three categories based on electrical and mechanical compatibility with the 25LC040AT-E/SN:

Category 1: Direct Electrical Equivalents (Identical Core Parameters) Parts matching all critical parameters: 4Kbit capacity, 512 x 8 organization, SPI interface, 10 MHz clock frequency, 2.5V–5.5V supply range, -40°C to 125°C operating temperature, and 8-SOIC package. These parts are functionally interchangeable without design modification.

Category 2: Enhanced Performance Variants (Higher Clock Frequency) Parts with identical memory capacity, organization, and package but operating at 20 MHz clock frequency. These parts feature reduced voltage supply range (1.8V–5.5V) and narrower operating temperature range (-40°C to 85°C). Higher clock frequency provides performance headroom but requires verification of application timing requirements.

Category 3: Legacy and Automotive-Grade Alternatives (Reduced Clock Frequency) Parts with 4Kbit capacity and SPI interface but operating at 5 MHz clock frequency. These include automotive-qualified variants with AEC-Q100 certification. Package variants include 8-SOP and 8-SOP-J configurations with slightly different physical dimensions (0.173", 4.40mm width). Reduced clock frequency and modified voltage/temperature ranges require application-level compatibility assessment.

Parameter Comparison

Part Number	Manufacturer	Memory Size	Clock Frequency	Voltage Supply	Operating Temp	Package	Status	Inventory
25LC040AT-E/SN	Microchip	4Kbit	10 MHz	2.5V–5.5V	-40°C–125°C	8-SOIC (3.90mm)	Active	11405
25LC040A-E/SN	Microchip	4Kbit	10 MHz	2.5V–5.5V	-40°C–125°C	8-SOIC (3.90mm)	Active	5100
AT25040B-SSHL-B	Microchip	4Kbit	20 MHz	1.8V–5.5V	-40°C–85°C	8-SOIC (3.90mm)	Active	9000
AT25040B-SSHL-T	Microchip	4Kbit	20 MHz	1.8V–5.5V	-40°C–85°C	8-SOIC (3.90mm)	Active	31335
BR25H040F-2CE2	Rohm	4Kbit	10 MHz	2.5V–5.5V	-40°C–125°C	8-SOP (4.40mm)	Active	1731
BR25H040F-2LBH2	Rohm	4Kbit	10 MHz	2.5V–5.5V	-40°C–125°C	8-SOP (4.40mm)	Active	1296
BR25H040FJ-2CE2	Rohm	4Kbit	10 MHz	2.5V–5.5V	-40°C–125°C	8-SOP-J (3.90mm)	Active	3173
BR25L040F-WE2	Rohm	4Kbit	5 MHz	1.8V–5.5V	-40°C–85°C	8-SOP (4.40mm)	Not For New Designs	1234
BR25L040FJ-WE2	Rohm	4Kbit	5 MHz	1.8V–5.5V	-40°C–85°C	8-SOP-J (3.90mm)	Not For New Designs	807
CAT25040VI-G	onsemi	4Kbit	Not Specified	1.8V–5.5V	-40°C–85°C	8-SOIC (3.90mm)	Obsolete	696
CAT25040VI-GT3	onsemi	4Kbit	Not Specified	1.8V–5.5V	-40°C–85°C	8-SOIC (3.90mm)	Active	49300

Engineering Selection Recommendations

For Direct Replacement (No Design Changes Required)

The 25LC040A-E/SN provides identical electrical and mechanical specifications to the 25LC040AT-E/SN with the same 10 MHz clock frequency, 2.5V–5.5V supply range, and -40°C to 125°C operating temperature. This part is the primary direct substitute and maintains full compatibility with existing PCB layouts and firmware implementations.

For Performance Enhancement Applications

The AT25040B-SSHL-T and AT25040B-SSHL-B variants operate at 20 MHz, providing doubled clock frequency for applications requiring faster data access. These parts reduce the voltage supply range to 1.8V–5.5V and narrow the operating temperature range to -40°C to 85°C. Selection requires confirmation that the application operates within these reduced specifications. The AT25040B-SSHL-T variant offers superior inventory availability (31335 units) compared to the -B variant.

For Automotive and Extended Temperature Applications

The BR25H040FJ-2CE2 from Rohm Semiconductor provides AEC-Q100 automotive qualification while maintaining the original 10 MHz clock frequency and -40°C to 125°C operating temperature range. This part uses 8-SOP-J packaging with identical 3.90mm width to the original part, ensuring PCB compatibility. The automotive-grade qualification supports applications requiring automotive-level reliability and traceability.

For Legacy System Maintenance

The BR25L040FJ-WE2 operates at reduced 5 MHz clock frequency with 8-SOP-J packaging matching the original 3.90mm width. This part is marked "Not For New Designs" and should be used only for maintenance of existing systems where the lower clock frequency is acceptable. The reduced frequency may impact data throughput in timing-critical applications.

For onsemi-Based Supply Chains

The CAT25040VI-GT3 from onsemi provides active production status with high inventory availability (49300 units). This part operates within the 1.8V–5.5V supply range and -40°C to 85°C temperature range. Clock frequency is not specified in the provided data; application-level compatibility assessment is required before selection.

Frequently Asked Questions (FAQ)

Q: Can I use the AT25040B-SSHL-T as a direct replacement for the 25LC040AT-E/SN?

A: The AT25040B-SSHL-T is electrically compatible for applications operating within its reduced specifications: 1.8V–5.5V supply voltage and -40°C to 85°C operating temperature. The doubled clock frequency (20 MHz vs. 10 MHz) provides performance headroom. If your application requires the full -40°C to 125°C temperature range or operates at supply voltages below 1.8V, this part is not suitable. The 8-SOIC package dimensions are identical, ensuring PCB compatibility.

Q: What is the difference between 8-SOIC, 8-SOP, and 8-SOP-J packages?

A: All three are 8-pin surface mount packages with different physical dimensions. The 8-SOIC (0.154", 3.90mm width) and 8-SOP-J (0.154", 3.90mm width) are mechanically identical and interchangeable on PCBs designed for either package. The 8-SOP (0.173", 4.40mm width) is wider and requires PCB layout verification before substitution. Pin pitch and lead configuration remain consistent across all variants.

Q: Why would I choose a 5 MHz part like BR25L040FJ-WE2 over the 10 MHz original?

A: The BR25L040FJ-WE2 should be selected only for maintenance of existing systems already using this part. For new designs, the 10 MHz variants provide superior performance without additional cost or complexity. The 5 MHz part is marked "Not For New Designs" and represents legacy technology. Reduced clock frequency may limit data throughput in applications requiring rapid sequential memory access.

Q: Are the Rohm BR25H040 variants compatible with the Microchip 25LC040AT-E/SN?

A: The BR25H040FJ-2CE2 and BR25H040F-2LBH2 are electrically compatible, maintaining the 10 MHz clock frequency, 2.5V–5.5V supply range, and -40°C to 125°C operating temperature. The BR25H040FJ-2CE2 includes AEC-Q100 automotive qualification. Package dimensions differ slightly (8-SOP vs. 8-SOIC), requiring PCB layout verification. The BR25H040F-2CE2 variant includes automotive qualification and is suitable for automotive applications.

Q: What does "Not For New Designs" status mean?

A: Parts marked "Not For New Designs" are in production but are not recommended for new product development. These parts typically represent older technology or are being phased out by manufacturers. Existing inventory may be available for maintenance and repair of legacy systems. New designs should select parts with "Active" status to ensure long-term supply availability and manufacturer support.

Q: Can I substitute the onsemi CAT25040VI-GT3 for the Microchip 25LC040AT-E/SN?

A: The CAT25040VI-GT3 is electrically compatible within its specified operating range: 1.8V–5.5V supply voltage and -40°C to 85°C operating temperature. The 8-SOIC package dimensions are identical. Clock frequency is not specified in the provided data; application timing requirements must be assessed independently. The part is in active production with high inventory availability (49300 units).

Q: What compliance certifications should I verify before substitution?

A: All listed parts maintain ROHS3 compliance and REACH unaffected status, matching the original 25LC040AT-E/SN. The BR25H040FJ-2CE2 and BR25H040F-2CE2 include AEC-Q100 automotive qualification for applications requiring automotive-grade reliability. Moisture sensitivity levels vary: most parts are rated MSL 1 (Unlimited), while AT25040B-SSHL-B is rated MSL 3 (168 Hours). Verify moisture handling requirements for your manufacturing process before selection.

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