LM2576BU Buck Switching Regulator IC Equivalent & Substitute Parts

Part Overview

The LM2576BU is a buck switching regulator IC manufactured by Microchip Technology, designed for positive adjustable output applications with 3A output current capability. This part operates in the TO-263-6 (D2PAK) package and is classified as obsolete. Due to its obsolete status, identifying functionally equivalent and mechanically compatible substitute parts is essential for design continuity, procurement flexibility, and long-term product support.

Key Parameters

Parameter	Value
Function	Step-Down (Buck)
Output Configuration	Positive
Output Type	Adjustable
Number of Outputs	1
Voltage - Input (Min)	4V
Voltage - Input (Max)	40V
Voltage - Output (Min/Fixed)	1.23V
Voltage - Output (Max)	37V
Current - Output	3A
Frequency - Switching	52kHz
Synchronous Rectifier	No
Operating Temperature	-40°C ~ 125°C (TJ)
Mounting Type	Surface Mount
Package / Case	TO-263-6, D2PAK (5 Leads + Tab)
Moisture Sensitivity Level (MSL)	3 (168 Hours)

Substitute Part Grouping Explanation

Substitute parts for the LM2576BU are grouped based on strict electrical and mechanical compatibility criteria. The primary substitution parameters are:

Topology & Function: Buck (step-down) switching regulator
Output Configuration: Positive adjustable output
Output Current: 3A capability
Input Voltage Range: 4V to 40V minimum compatibility
Output Voltage Range: 1.23V to 37V minimum compatibility
Package: TO-263-6 (D2PAK, 5 Leads + Tab)
Switching Frequency: 52kHz nominal operation
Temperature Range: -40°C to 125°C

Parts are classified into two categories:

Category 1 - Direct Electrical & Mechanical Equivalents (3A Output Current)

LM2576WU (Microchip Technology) - Active status, identical electrical specifications
AP1501-K5G-13 (Diodes Incorporated) - Active status, identical output current, higher switching frequency (150kHz)
LM2596DSADJG (onsemi) - Active status, multi-topology capable, identical output current
LM2596DSADJR4G (onsemi) - Active status, multi-topology capable, identical output current

Category 2 - Reduced Output Current Substitutes (1A Output Current)

LM2575S-ADJ/NOPB (Texas Instruments) - Active status, reduced output current to 1A
LM2575SX-ADJ/NOPB (Texas Instruments) - Active status, reduced output current to 1A
TL2575-ADJIKTTR (Texas Instruments) - Active status, reduced output current to 1A
TL2575-ADJIKTTRG3 (Texas Instruments) - Active status, reduced output current to 1A
TL2575HV-ADJIKTTR (Texas Instruments) - Active status, reduced output current to 1A, extended input voltage to 60V

Parameter Comparison

Part Number	Manufacturer	Product Status	Output Current	Input Voltage (Min)	Input Voltage (Max)	Output Voltage (Min)	Output Voltage (Max)	Switching Frequency	Package	RoHS Status
LM2576BU	Microchip Technology	Obsolete	3A	4V	40V	1.23V	37V	52kHz	TO-263-6	RoHS Non-Compliant
LM2576WU	Microchip Technology	Active	3A	4V	40V	1.23V	37V	52kHz	TO-263-6	RoHS3 Compliant
AP1501-K5G-13	Diodes Incorporated	Active	3A	4.5V	40V	1.23V	37V	150kHz	TO-263-6	RoHS3 Compliant
LM2596DSADJG	onsemi	Active	3A	4.5V	40V	1.23V	37V	150kHz	TO-263-6	RoHS3 Compliant
LM2596DSADJR4G	onsemi	Active	3A	4.5V	40V	1.23V	37V	150kHz	TO-263-6	RoHS3 Compliant
LM2575S-ADJ/NOPB	Texas Instruments	Active	1A	4V	40V	1.23V	37V	52kHz	TO-263-6	RoHS3 Compliant
LM2575SX-ADJ/NOPB	Texas Instruments	Active	1A	4V	40V	1.23V	37V	52kHz	TO-263-6	RoHS3 Compliant
TL2575-ADJIKTTR	Texas Instruments	Active	1A	4.75V	40V	1.23V	37V	52kHz	TO-263-6	RoHS3 Compliant
TL2575-ADJIKTTRG3	Texas Instruments	Active	1A	4.75V	40V	1.23V	37V	52kHz	TO-263-6	RoHS3 Compliant
TL2575HV-ADJIKTTR	Texas Instruments	Active	1A	4.75V	60V	1.23V	57V	52kHz	TO-263-6	RoHS3 Compliant

Engineering Selection Recommendations

For Direct Replacement (3A Output Current Requirement)

LM2576WU is the primary direct substitute. It maintains identical electrical specifications to the LM2576BU while offering active product status and RoHS3 compliance. Both parts operate at 52kHz switching frequency with matching input/output voltage ranges and 3A output current capability.

AP1501-K5G-13 and LM2596DSADJG/LM2596DSADJR4G are functionally equivalent alternatives with 3A output current. These parts operate at 150kHz switching frequency, which may require circuit design review for EMI characteristics and component selection. All three alternatives are in active production with RoHS3 compliance.

For Reduced Current Applications (1A Output Current)

When application requirements permit reduced output current to 1A, the LM2575 and TL2575 series provide active alternatives. LM2575S-ADJ/NOPB and LM2575SX-ADJ/NOPB maintain the 52kHz switching frequency and 4V minimum input voltage of the original part. TL2575-ADJIKTTR and TL2575-ADJIKTTRG3 operate at 4.75V minimum input voltage. All are RoHS3 compliant and in active production.

TL2575HV-ADJIKTTR extends the input voltage range to 60V maximum, suitable for applications requiring higher input voltage tolerance beyond the standard 40V specification.

Compliance Considerations

The LM2576BU is RoHS non-compliant. All substitute parts listed are RoHS3 compliant, meeting modern regulatory requirements for new designs and procurement.

Frequently Asked Questions (FAQ)

Q: Can LM2576WU directly replace LM2576BU without circuit modifications?

A: Yes. LM2576WU is electrically and mechanically identical to LM2576BU. Both operate at 52kHz with 3A output current, identical input/output voltage ranges, and the same TO-263-6 package. The primary difference is product status (active vs. obsolete) and RoHS compliance.

Q: What is the impact of switching frequency differences between 52kHz and 150kHz?

A: Higher switching frequency (150kHz in AP1501-K5G-13 and LM2596 series) reduces output filter component size but may increase EMI emissions and switching losses. Circuit design review is required to confirm compatibility with existing PCB layouts and filter designs.

Q: Can I use a 1A output current part (LM2575 series) in place of the 3A LM2576BU?

A: Only if your application requires maximum output current of 1A or less. The LM2575 series is not suitable for applications requiring the full 3A capability of the LM2576BU. Exceeding the rated output current will cause thermal shutdown and circuit failure.

Q: What is the minimum input voltage difference between LM2576BU and TL2575 series?

A: LM2576BU and LM2575S-ADJ/NOPB operate at 4V minimum input voltage. TL2575-ADJIKTTR and TL2575-ADJIKTTRG3 require 4.75V minimum input voltage. Applications operating below 4.75V must use the LM2575S or LM2576WU variants.

Q: Are all substitute parts available in the same packaging options?

A: All substitute parts listed are available in TO-263-6 (D2PAK, 5 Leads + Tab) surface mount package. Packaging options (Tube, Tape & Reel, Cut Tape) vary by manufacturer and part number. Confirm packaging availability with your supplier for procurement requirements.

Q: What is the MSL (Moisture Sensitivity Level) consideration for these parts?

A: LM2576BU, LM2576WU, and TL2575 series are MSL 3 (168 Hours). LM2596DSADJG and LM2596DSADJR4G are MSL 1 (Unlimited). MSL 1 parts have no moisture sensitivity restrictions and are preferred for long-term storage and high-humidity environments.

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