LM2575-12BU Equivalent & Substitute Parts

Part Overview

The LM2575-12BU is a buck switching regulator IC from Microchip Technology designed for step-down voltage conversion with a fixed 12V output and 1A current capacity. This device operates across a 4V to 40V input range and is housed in a TO-263-6 D2PAK package with 5 leads plus tab. The LM2575-12BU is classified as obsolete, making equivalent and substitute parts necessary for new designs and ongoing production requirements.

Key Parameters

Parameter	Value
Function	Step-Down (Buck)
Output Configuration	Positive
Output Type	Fixed
Output Voltage	12V
Number of Outputs	1
Input Voltage Range	4V to 40V
Output Current	1A
Switching Frequency	52kHz
Operating Temperature	-40°C to 125°C (TJ)
Package Type	TO-263-6, D2PAK (5 Leads + Tab)
Mounting Type	Surface Mount
Product Status	Obsolete

Substitute Part Grouping Explanation

Substitution for the LM2575-12BU is determined by the following critical parameters:

Output Voltage: 12V fixed output (non-negotiable)
Package Compatibility: TO-263-6 D2PAK (5 Leads + Tab) footprint
Topology: Buck switching regulator
Output Configuration: Positive fixed output
Operating Temperature Range: -40°C to 125°C (TJ)
Mounting Type: Surface Mount

Substitute parts are grouped into two categories based on output current capacity:

Category 1 - Direct Current Rating (1A Output): Parts maintaining the original 1A output current specification with identical switching frequency (52kHz) and input voltage range compatibility.

Category 2 - Enhanced Current Rating (3A Output): Parts with increased output current capacity (3A) while maintaining the same 12V fixed output, package footprint, and operating temperature range. These parts operate at higher switching frequency (150kHz) but remain pin-compatible and functionally equivalent for applications not requiring the full 1A specification.

Parameter Comparison

Parameter	LM2575-12BU	LM2575-12WU	LM2596S-12/NOPB	LM2596SX-12/NOPB	NCV2575D2T-12R4G	TL2575-12IKTTR
Manufacturer	Microchip	Microchip	Texas Instruments	Texas Instruments	onsemi	Texas Instruments
Output Voltage	12V	12V	12V	12V	12V	12V
Output Current	1A	1A	3A	3A	1A	1A
Input Voltage (Min)	4V	4V	4.5V	4.5V	4.75V	4.75V
Input Voltage (Max)	40V	40V	40V	40V	40V	40V
Switching Frequency	52kHz	52kHz	150kHz	150kHz	52kHz	52kHz
Operating Temperature	-40°C to 125°C	-40°C to 125°C	-40°C to 125°C	-40°C to 125°C	-40°C to 125°C	-40°C to 125°C
Package	TO-263-6	TO-263-6	TO-263-6	TO-263-6	TO-263-6	TO-263-6
Product Status	Obsolete	Active	Active	Active	Obsolete	Active
RoHS Status	Non-compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant

Engineering Selection Recommendations

Primary Recommendation - LM2575-12WU (Microchip Technology)

The LM2575-12WU is the direct equivalent to the LM2575-12BU, maintaining identical electrical specifications including 1A output current and 52kHz switching frequency. This part is currently in active production status with ROHS3 compliance, addressing the obsolescence of the original part. The LM2575-12WU is available in tube packaging with 7400 units in stock, providing immediate availability for production requirements.

Secondary Recommendation - TL2575-12IKTTR (Texas Instruments)

The TL2575-12IKTTR offers equivalent performance with 1A output current and 52kHz switching frequency. This part maintains active product status with ROHS3 compliance and is available in cut tape and Digi-Reel packaging. Input voltage minimum specification is 4.75V compared to the original 4V, which is acceptable for most applications within the 4V to 40V operating range.

Alternative for Higher Current Applications - LM2596S-12/NOPB or LM2596SX-12/NOPB (Texas Instruments)

For applications requiring increased current capacity, the LM2596S-12/NOPB and LM2596SX-12/NOPB provide 3A output current while maintaining the same 12V fixed output and TO-263-6 package footprint. These parts operate at 150kHz switching frequency and are ROHS3 compliant with active product status. The LM2596SX-12/NOPB variant offers superior inventory availability with 35401 units in stock.

Tertiary Option - NCV2575D2T-12R4G (onsemi)

The NCV2575D2T-12R4G maintains 1A output current and 52kHz switching frequency specifications. Although classified as obsolete, this part is ROHS3 compliant with 5800 units available. Input voltage minimum is 4.75V. This option is suitable only when other active alternatives are unavailable.

Frequently Asked Questions (FAQ)

Q: Can I use LM2596S-12/NOPB or LM2596SX-12/NOPB as direct replacements for LM2575-12BU?

A: Yes, these parts are pin-compatible and functionally equivalent. Both maintain the same 12V fixed output and TO-263-6 package. The primary differences are increased output current capacity (3A versus 1A) and higher switching frequency (150kHz versus 52kHz). These differences do not prevent substitution; the higher current rating provides additional design margin, and the higher switching frequency may reduce output filter component sizes.

Q: What is the minimum input voltage difference between the LM2575-12BU and substitute parts?

A: The LM2575-12BU specifies 4V minimum input voltage. The LM2596S-12/NOPB, LM2596SX-12/NOPB, NCV2575D2T-12R4G, and TL2575-12IKTTR specify 4.75V minimum. The LM2575-12WU maintains 4V minimum. For applications requiring operation below 4.75V, use LM2575-12WU or verify that your input voltage remains above 4.75V.

Q: Are all substitute parts ROHS3 compliant?

A: All active substitute parts (LM2575-12WU, LM2596S-12/NOPB, LM2596SX-12/NOPB, and TL2575-12IKTTR) are ROHS3 compliant. The NCV2575D2T-12R4G is also ROHS3 compliant but is classified as obsolete. The original LM2575-12BU is RoHS non-compliant.

Q: Does switching frequency affect circuit design when substituting parts?

A: Switching frequency differences (52kHz versus 150kHz) may affect output filter design and EMI characteristics. Higher switching frequency typically allows smaller filter components but may require different PCB layout considerations. Verify that your circuit design accommodates the substitute part's switching frequency before implementation.

Q: Which substitute part offers the best inventory availability?

A: The LM2596SX-12/NOPB from Texas Instruments offers the highest inventory availability with 35401 units in stock. The LM2575-12WU from Microchip provides 7400 units, and the NCV2575D2T-12R4G from onsemi provides 5800 units.

Q: Can I use a 1A-rated part in an application designed for 3A output?

A: No. Using a 1A-rated part in a 3A application will result in thermal stress and potential device failure. Use only parts with output current ratings equal to or greater than your application requirement.

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