LM2575-3.3BU TR Equivalent & Substitute Parts

Part Overview

The LM2575-3.3BU TR is a buck switching regulator IC manufactured by Microchip Technology, designed to deliver a fixed 3.3V output at 1A from input voltages ranging from 4V to 40V. This device operates at a switching frequency of 52kHz and is housed in a TO-263-6 (D2PAK) surface mount package with 5 leads plus tab. The part is classified as obsolete, which necessitates identification of active equivalent and substitute components for new designs and ongoing production requirements. Substitute parts are selected based on matching electrical specifications, package compatibility, and functional equivalence in buck regulator topology.

Key Parameters

Parameter	Value
Function	Step-Down (Buck)
Output Configuration	Positive
Output Type	Fixed
Output Voltage	3.3V
Output Current	1A
Input Voltage Range	4V to 40V
Switching Frequency	52kHz
Package Type	TO-263-6 (D2PAK, 5 Leads + Tab)
Mounting Type	Surface Mount
Operating Temperature	-40°C to 125°C (TJ)
Synchronous Rectifier	No
Part Status	Obsolete

Substitute Part Grouping Explanation

Substitute parts for the LM2575-3.3BU TR are grouped into two categories based on electrical and mechanical compatibility:

Category 1: Direct Functional Equivalents (1A Output Current) These parts maintain the same 1A output current specification and 52kHz switching frequency as the original part. They are suitable for direct replacement in applications where the 1A current rating is sufficient.

Category 2: Enhanced Performance Substitutes (2A and 3A Output Current) These parts provide higher output current ratings (2A or 3A) while maintaining the same 3.3V fixed output voltage and compatible TO-263-6 package. These are suitable for applications requiring higher current delivery or where design margin is desired.

Key Parameters Determining Substitution:

Output voltage: 3.3V (fixed)
Package type: TO-263-6 (D2PAK, 5 Leads + Tab)
Mounting type: Surface Mount
Operating temperature range: -40°C to 125°C
Output configuration: Positive
Topology: Buck (Step-Down)
Number of outputs: 1

Parameter Comparison

Part Number	Manufacturer	Status	Output Current	Input Voltage (Min)	Input Voltage (Max)	Switching Frequency	Package	RoHS Compliance
LM2575-3.3BU TR	Microchip Technology	Obsolete	1A	4V	40V	52kHz	TO-263-6	Non-compliant
LM2575-3.3WU-TR	Microchip Technology	Active	1A	4V	40V	52kHz	TO-263-6	ROHS3 Compliant
TL2575-33IKTTR	Texas Instruments	Active	1A	4.75V	40V	52kHz	TO-263-6	ROHS3 Compliant
LM2592HVS-3.3/NOPB	Texas Instruments	Active	2A	4.5V	60V	150kHz	TO-263-6	ROHS3 Compliant
LM2592HVSX-3.3/NOPB	Texas Instruments	Active	2A	4.5V	60V	150kHz	TO-263-6	ROHS3 Compliant
LM2596S-3.3/NOPB	Texas Instruments	Active	3A	4.5V	40V	150kHz	TO-263-6	ROHS3 Compliant
LM2596SX-3.3/NOPB	Texas Instruments	Active	3A	4.5V	40V	150kHz	TO-263-6	ROHS3 Compliant

Engineering Selection Recommendations

For Direct Replacement (1A Applications):

The LM2575-3.3WU-TR is the primary direct substitute for the obsolete LM2575-3.3BU TR. Both parts are manufactured by Microchip Technology, share identical electrical specifications (1A output, 4V to 40V input range, 52kHz switching frequency), and use the same TO-263-6 package. The LM2575-3.3WU-TR is active in production and ROHS3 compliant, making it suitable for new designs and production continuity.

The TL2575-33IKTTR from Texas Instruments is an alternative direct replacement with equivalent 1A output current and 52kHz switching frequency. This part has a minimum input voltage specification of 4.75V (compared to 4V for the original), which should be evaluated against specific application requirements. The TL2575-33IKTTR is active and ROHS3 compliant.

For Enhanced Performance (Higher Current Applications):

The LM2592HVS-3.3/NOPB and LM2592HVSX-3.3/NOPB provide 2A output current with extended input voltage range (4.5V to 60V) and higher switching frequency (150kHz). These parts are suitable for applications requiring higher current delivery or improved transient response.

The LM2596S-3.3/NOPB and LM2596SX-3.3/NOPB deliver 3A output current, providing maximum design margin. Both maintain the 3.3V output voltage and TO-263-6 package compatibility. The input voltage range is 4.5V to 40V, matching the original part's maximum specification.

All substitute parts are active in production status and ROHS3 compliant, supporting modern manufacturing and environmental requirements.

Frequently Asked Questions (FAQ)

Q: Can the LM2575-3.3WU-TR be used as a direct replacement for the LM2575-3.3BU TR?

A: Yes. Both parts are manufactured by Microchip Technology and share identical electrical specifications: 1A output current, 4V to 40V input voltage range, 52kHz switching frequency, and TO-263-6 package. The LM2575-3.3WU-TR is active in production and ROHS3 compliant, whereas the original part is obsolete and non-compliant.

Q: What is the difference between the 1A and 2A/3A substitute options?

A: The 1A substitutes (LM2575-3.3WU-TR and TL2575-33IKTTR) maintain the original output current specification. The 2A substitutes (LM2592 series) and 3A substitutes (LM2596 series) provide higher current capacity. Selection depends on application current requirements. Higher-rated parts can be used in lower-current applications but will occupy the same board space and package footprint.

Q: Are all substitute parts compatible with the same PCB layout?

A: Yes. All substitute parts use the TO-263-6 (D2PAK) package with 5 leads plus tab, ensuring mechanical and electrical pin compatibility. PCB layouts designed for the LM2575-3.3BU TR can accommodate any of the listed substitutes without modification.

Q: What is the minimum input voltage difference between the original part and substitutes?

A: The LM2575-3.3BU TR and LM2575-3.3WU-TR specify 4V minimum input voltage. The TL2575-33IKTTR specifies 4.75V minimum. The LM2592 and LM2596 series specify 4.5V minimum. Applications operating below 4.5V input voltage should use the Microchip LM2575 variants.

Q: Do the higher switching frequency substitutes (150kHz vs. 52kHz) affect circuit design?

A: The LM2592 and LM2596 series operate at 150kHz compared to the original 52kHz. Higher switching frequency allows for smaller external filter components but may require PCB layout optimization to minimize EMI. Existing filter component values designed for 52kHz operation should be evaluated for the higher frequency parts.

Q: Which substitute offers the best inventory availability?

A: The LM2596SX-3.3/NOPB has the highest inventory level at 25,400 pieces. The LM2596S-3.3/NOPB has 2,700 pieces. Both provide excellent availability for production requirements.

Q: Are all substitutes ROHS3 compliant?

A: Yes. All active substitute parts listed are ROHS3 compliant. The original LM2575-3.3BU TR is RoHS non-compliant. For applications requiring RoHS compliance, any of the listed substitutes is suitable.

Q: What is the difference between tube and tape & reel packaging options?

A: Tube packaging is suitable for manual assembly and lower-volume applications. Tape & Reel (TR) and Cut Tape (CT) & Digi-Reel packaging are designed for automated pick-and-place assembly. Selection depends on manufacturing process requirements. All packaging options contain the same die and electrical specifications.

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