LM2576BT Equivalent & Substitute Parts

Part Overview

The LM2576BT is a buck switching regulator IC from Microchip Technology designed for step-down voltage conversion with positive adjustable output. It delivers 3A output current across an input voltage range of 4V to 40V, with adjustable output from 1.23V to 37V. The device operates at a fixed switching frequency of 52kHz and is housed in a TO-220-5 through-hole package.

The LM2576BT is classified as obsolete. Identifying equivalent and substitute parts is necessary to ensure design continuity, maintain supply chain reliability, and access components with active manufacturing status and current compliance certifications.

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 to 125°C (TJ)
Package / Case	TO-220-5
Mounting Type	Through Hole

Substitute Part Grouping Explanation

Substitution of the LM2576BT is determined by the following critical parameters:

Electrical Compatibility: Input voltage range (4V to 40V minimum), adjustable output voltage range (1.23V to 37V), switching frequency (52kHz), and output current capability must meet or exceed the original specification.

Mechanical Compatibility: Package type (TO-220-5) and mounting method (through hole) must be identical to ensure PCB layout compatibility without redesign.

Functional Equivalence: Buck topology, positive output configuration, single output, and non-synchronous rectifier design must be maintained.

Substitute parts are grouped into two categories:

Direct Equivalent: Parts with identical electrical specifications and package, differing only in manufacturer or product status.

Functional Equivalent: Parts with compatible electrical specifications within the allowed parameter ranges, same package, but potentially different output current ratings or input voltage minimums.

Parameter Comparison

Parameter	LM2576BT (Main)	LM2576WT (Direct Equivalent)	LM2575T-ADJG (Functional Equivalent)
Manufacturer	Microchip Technology	Microchip Technology	onsemi
Product Status	Obsolete	Active	Active
Function	Step-Down	Step-Down	Step-Down
Output Configuration	Positive	Positive	Positive
Output Type	Adjustable	Adjustable	Adjustable
Number of Outputs	1	1	1
Voltage - Input (Min)	4V	4V	4.75V
Voltage - Input (Max)	40V	40V	40V
Voltage - Output (Min/Fixed)	1.23V	1.23V	1.23V
Voltage - Output (Max)	37V	37V	37V
Current - Output	3A	3A	1A
Frequency - Switching	52kHz	52kHz	52kHz
Synchronous Rectifier	No	No	No
Operating Temperature	-40°C to 125°C (TJ)	-40°C to 125°C (TJ)	-40°C to 125°C (TJ)
Package / Case	TO-220-5	TO-220-5	TO-220-5
Mounting Type	Through Hole	Through Hole	Through Hole
RoHS Status	RoHS non-compliant	ROHS3 Compliant	ROHS3 Compliant

Engineering Selection Recommendations

LM2576WT (Direct Equivalent - Recommended Primary Choice)

The LM2576WT is manufactured by Microchip Technology and maintains identical electrical specifications to the LM2576BT: 3A output current, 4V to 40V input range, 1.23V to 37V adjustable output, and 52kHz switching frequency. The device is housed in the same TO-220-5 package. The LM2576WT holds active product status and is ROHS3 compliant, providing access to current manufacturing and regulatory compliance. This part is the direct functional and electrical replacement with no design modifications required.

LM2575T-ADJG (Functional Equivalent - Alternative Option)

The LM2575T-ADJG is manufactured by onsemi and provides functional equivalence with the following considerations: it maintains the same adjustable output voltage range (1.23V to 37V), switching frequency (52kHz), and TO-220-5 package. However, the output current is rated at 1A compared to the LM2576BT's 3A, and the minimum input voltage is 4.75V versus 4V. The LM2575T-ADJG is suitable only for applications where the required output current does not exceed 1A and the input voltage remains at or above 4.75V. This part is active and ROHS3 compliant. Selection of this part requires verification that application current requirements do not exceed 1A.

Frequently Asked Questions (FAQ)

Q: Can the LM2576WT be used as a direct replacement for the LM2576BT without PCB modifications?

A: Yes. The LM2576WT is electrically and mechanically identical to the LM2576BT. Both devices use the TO-220-5 package, have identical pin configurations, and share the same electrical specifications. No PCB layout changes are required.

Q: What is the key limitation of the LM2575T-ADJG compared to the LM2576BT?

A: The LM2575T-ADJG has a maximum output current rating of 1A, whereas the LM2576BT is rated for 3A. Additionally, the LM2575T-ADJG requires a minimum input voltage of 4.75V compared to 4V for the LM2576BT. These differences restrict the LM2575T-ADJG to lower-power applications.

Q: Why is the LM2576BT classified as obsolete?

A: The LM2576BT is no longer in active production. The LM2576WT serves as the current active equivalent from Microchip Technology and should be used for new designs and ongoing supply requirements.

Q: Are there compliance differences between the substitute parts and the original LM2576BT?

A: Yes. The LM2576BT is RoHS non-compliant. Both substitute parts, LM2576WT and LM2575T-ADJG, are ROHS3 compliant. All three parts are REACH unaffected and carry the same ECCN and HTSUS classifications.

Q: Can the LM2575T-ADJG be used in applications originally designed for the LM2576BT?

A: Only if the application's maximum output current requirement does not exceed 1A and the minimum input voltage is 4.75V or higher. If the original design requires 3A output current or operates with input voltages below 4.75V, the LM2575T-ADJG is not suitable. The LM2576WT is the appropriate choice for full compatibility.

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