LM2575SX-3.3 Equivalent & Substitute Parts

Part Overview

The LM2575SX-3.3 is a buck switching regulator IC from Texas Instruments, part of the SIMPLE SWITCHER® series. It delivers a fixed 3.3V output at 1A from input voltages ranging from 4V to 40V, operating at a 52kHz switching frequency. The device is housed in a TO-263-6 (D2PAK) surface mount package with 5 leads plus tab.

This part is currently listed as obsolete. Identifying equivalent and substitute parts is necessary to maintain design continuity, ensure supply chain reliability, and support ongoing production or maintenance requirements.

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
Operating Temperature	-40°C to 125°C (TJ)
Package	TO-263-6, D2PAK (5 Leads + Tab)
Mounting Type	Surface Mount
Synchronous Rectifier	No

Substitute Part Grouping Explanation

Substitution for the LM2575SX-3.3 is determined by the following critical parameters:

Output Voltage: Must be fixed at 3.3V
Output Current: Minimum 1A capability
Input Voltage Range: Must accommodate 4V to 40V (or higher)
Package: TO-263-6 (D2PAK) surface mount configuration
Topology: Buck switching regulator
Switching Frequency: 52kHz operation
Temperature Range: -40°C to 125°C minimum

Substitute parts are grouped into two categories:

Direct Equivalents (1A Output): Parts with identical 1A output current rating, matching all core electrical specifications and package requirements.

Higher Current Alternatives (3A Output): Parts with 3A output capability, suitable for designs requiring increased current headroom while maintaining the same voltage regulation and package form factor.

Parameter Comparison

Part Number	Manufacturer	Output Current	Input Voltage (Min)	Input Voltage (Max)	Switching Frequency	Operating Temperature	Product Status	RoHS Status
LM2575SX-3.3	Texas Instruments	1A	4V	40V	52kHz	-40°C to 125°C	Obsolete	Non-compliant
LM2575SX-3.3/NOPB	Texas Instruments	1A	4V	40V	52kHz	-40°C to 125°C	Active	ROHS3 Compliant
TL2575-33IKTTR	Texas Instruments	1A	4.75V	40V	52kHz	-40°C to 125°C	Active	ROHS3 Compliant
TL2575HV-33IKTTR	Texas Instruments	1A	4.75V	60V	52kHz	-40°C to 125°C	Active	ROHS3 Compliant
LM2575-3.3WU	Microchip Technology	1A	4V	40V	52kHz	-40°C to 125°C	Active	ROHS3 Compliant
LM2576-3.3WU	Microchip Technology	3A	4V	40V	52kHz	-40°C to 125°C	Active	ROHS3 Compliant
LM2576-3.3WU-TR	Microchip Technology	3A	4V	40V	52kHz	-40°C to 125°C	Active	ROHS3 Compliant
MIC4576-3.3WU	Microchip Technology	3A	4V	36V	200kHz	-40°C to 85°C	Active	ROHS3 Compliant
MIC4576-3.3WU-TR	Microchip Technology	3A	4V	36V	200kHz	-40°C to 85°C	Active	ROHS3 Compliant

Engineering Selection Recommendations

Primary Recommendation: LM2575SX-3.3/NOPB (Texas Instruments)

This part is the direct equivalent of the obsolete LM2575SX-3.3, maintaining identical electrical specifications and package configuration. It is currently active in production and ROHS3 compliant, making it the preferred choice for direct replacement without design modification.

Secondary Recommendation: LM2575-3.3WU (Microchip Technology)

This part provides equivalent 1A output current and matching input voltage range (4V to 40V). It is active and ROHS3 compliant. The primary difference is packaging format (Tube vs. original packaging), which does not affect electrical performance or board-level compatibility.

Higher Current Alternative: LM2576-3.3WU or LM2576-3.3WU-TR (Microchip Technology)

These parts offer 3A output current capability while maintaining the same 3.3V output voltage, 52kHz switching frequency, and -40°C to 125°C operating range. They are suitable for designs requiring increased current capacity without changing the package footprint or topology. Available in both Tube and Tape & Reel packaging.

Extended Input Voltage Option: TL2575HV-33IKTTR (Texas Instruments)

This part supports input voltages up to 60V (compared to 40V for the original), while maintaining all other specifications. It is active and ROHS3 compliant. Use this variant only if your application requires the extended input voltage range.

Note on MIC4576 Series: The MIC4576-3.3WU and MIC4576-3.3WU-TR variants operate at 200kHz switching frequency and support maximum input voltage of 36V with a reduced operating temperature range (-40°C to 85°C). These differences may impact PCB layout, EMI characteristics, and thermal performance. Select only if these specifications align with your design requirements.

Frequently Asked Questions (FAQ)

Q: Can I use LM2575SX-3.3/NOPB as a direct replacement for LM2575SX-3.3?

A: Yes. LM2575SX-3.3/NOPB is electrically and mechanically identical to the obsolete LM2575SX-3.3. The primary difference is product status (Active vs. Obsolete) and RoHS compliance (ROHS3 Compliant vs. Non-compliant). No design changes are required.

Q: What is the difference between 1A and 3A output current variants?

A: The 1A variants (LM2575 series) are designed for applications requiring up to 1A output current. The 3A variants (LM2576 and MIC4576 series) provide higher current capability for more demanding loads. Both maintain the same 3.3V output voltage and TO-263-6 package. Select based on your application's current requirements.

Q: Why does TL2575HV-33IKTTR have a higher maximum input voltage (60V vs. 40V)?

A: The TL2575HV variant is designed for applications requiring extended input voltage range. The "HV" designation indicates high-voltage capability. Use this part only if your design requires input voltages above 40V. For standard 4V to 40V applications, the standard TL2575-33IKTTR is appropriate.

Q: What is the significance of the minimum input voltage difference (4V vs. 4.75V)?

A: The LM2575SX-3.3 and LM2575-3.3WU support minimum input voltage of 4V, while TL2575 variants specify 4.75V minimum. If your application operates below 4.75V input, use parts with 4V minimum specification. For applications above 4.75V, both are suitable.

Q: How does switching frequency affect my design?

A: The LM2575SX-3.3 operates at 52kHz. Most substitute parts maintain this frequency. The MIC4576 series operates at 200kHz, which typically results in smaller output filter components but may require different PCB layout considerations and EMI filtering. Verify compatibility with your existing board design before selecting the MIC4576 variant.

Q: What is the difference between Tube and Tape & Reel packaging?

A: Tube packaging is suitable for manual assembly or small-volume production. Tape & Reel (TR) packaging is optimized for automated pick-and-place assembly in high-volume manufacturing. Both contain identical components; the difference is in handling and assembly method. Select based on your production process.

Q: Can I use MIC4576-3.3WU if my application requires -40°C to 125°C operation?

A: No. The MIC4576 series is rated for -40°C to 85°C operating temperature. If your application requires operation up to 125°C, use LM2575, LM2576, or TL2575 variants, which all support the full -40°C to 125°C range.

Q: Are all substitute parts ROHS3 compliant?

A: All active substitute parts listed are ROHS3 compliant. The original LM2575SX-3.3 is listed as RoHS non-compliant. If RoHS compliance is required for your application, select from the active substitute parts.

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