LE25FU406BMB-TLM-H Equivalent & Substitute Parts

Part Overview

The LE25FU406BMB-TLM-H is a 4Mbit SPI FLASH memory IC manufactured by onsemi, designed for non-volatile data storage applications requiring serial peripheral interface communication. This device operates at 30 MHz clock frequency with a supply voltage range of 2.3V to 3.6V and is housed in an 8-SOIC package. The product is classified as obsolete, making identification of functionally compatible alternatives essential for ongoing system support and new design implementations.

Key Parameters

Parameter	Value
Memory Size	4Mbit
Memory Organization	512K x 8
Memory Interface	SPI
Clock Frequency	30 MHz
Voltage Supply Range	2.3V ~ 3.6V
Operating Temperature	0°C ~ 70°C
Package Type	8-SOIC (0.154", 3.90mm Width)
Write Cycle Time	2.5ms
Moisture Sensitivity Level	3 (168 Hours)

Substitute Part Grouping Explanation

Substitution of the LE25FU406BMB-TLM-H is determined by the following critical parameters:

Memory Capacity: 4Mbit (512K x 8 organization) — substitute must match this capacity
Interface Protocol: SPI — substitute must support identical serial communication protocol
Package Footprint: 8-SOIC with 0.154" width and 3.90mm body — substitute must be mechanically compatible
Supply Voltage: 2.3V ~ 3.6V — substitute must operate within or encompass this range
Pin Configuration: 8-pin SOIC package — substitute must maintain identical pinout

The LE25U40CMDTWG qualifies as a direct substitute based on matching memory capacity, SPI interface, identical package dimensions, and overlapping supply voltage specifications. Enhanced clock frequency (40 MHz vs. 30 MHz) and extended operating temperature range (-40°C ~ 85°C vs. 0°C ~ 70°C) represent functional improvements that maintain backward compatibility.

Parameter Comparison

Parameter	LE25FU406BMB-TLM-H	LE25U40CMDTWG
Manufacturer	onsemi	onsemi
Memory Size	4Mbit	4Mbit
Memory Organization	512K x 8	512K x 8
Memory Interface	SPI	SPI
Clock Frequency	30 MHz	40 MHz
Write Cycle Time	2.5ms	5ms
Voltage Supply Range	2.3V ~ 3.6V	2.3V ~ 3.6V
Operating Temperature	0°C ~ 70°C	-40°C ~ 85°C
Package Type	8-SOIC (0.154", 3.90mm Width)	8-SOIC (0.154", 3.90mm Width)
Product Status	Obsolete	Obsolete
Moisture Sensitivity Level	3 (168 Hours)	2 (1 Year)
RoHS Status	Not specified	ROHS3 Compliant

Engineering Selection Recommendations

The LE25U40CMDTWG is a qualified substitute for the LE25FU406BMB-TLM-H based on identical memory capacity, organization, interface protocol, and package footprint. Both devices are manufactured by onsemi and share the same supply voltage specification.

The substitute device provides enhanced specifications: increased clock frequency (40 MHz), extended operating temperature range (-40°C ~ 85°C), improved moisture sensitivity rating (MSL 2 vs. MSL 3), and RoHS3 compliance certification. These enhancements do not introduce incompatibility with existing designs specified for the original part.

Both parts are classified as obsolete. Selection between these devices should be based on application-specific requirements for operating temperature range, clock frequency margin, and compliance certifications. The LE25U40CMDTWG is suitable for applications requiring extended temperature operation or enhanced environmental protection.

Frequently Asked Questions (FAQ)

Q: Can LE25U40CMDTWG directly replace LE25FU406BMB-TLM-H in existing designs?

A: Yes. Both devices share identical memory capacity (4Mbit), organization (512K x 8), SPI interface, 8-SOIC package footprint, and supply voltage range (2.3V ~ 3.6V). Pin configuration and functional operation are compatible.

Q: What are the key differences between these parts?

A: The substitute operates at 40 MHz clock frequency versus 30 MHz, supports extended temperature range (-40°C ~ 85°C vs. 0°C ~ 70°C), has improved moisture sensitivity rating (MSL 2 vs. MSL 3), and carries RoHS3 compliance certification.

Q: Are there package compatibility concerns?

A: No. Both devices use 8-SOIC packaging with identical dimensions (0.154" width, 3.90mm body). PCB footprints and assembly processes are interchangeable.

Q: Does the higher clock frequency of the substitute affect compatibility?

A: No. The substitute's 40 MHz capability is a functional enhancement. Systems designed for 30 MHz operation remain fully compatible, as the substitute supports all lower clock frequencies.

Q: What is the significance of the MSL rating difference?

A: The substitute has MSL 2 (1 Year floor life) versus MSL 3 (168 Hours floor life) for the original part. This indicates improved moisture tolerance and extended shelf life for the substitute device.

Q: Are both parts still in production?

A: Both devices are classified as obsolete. Availability should be verified with authorized distributors before design implementation.

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