LM2575D2T-3.3R4 Equivalent & Substitute Parts

Part Overview

The LM2575D2T-3.3R4 is a buck switching regulator IC manufactured by onsemi, delivering a fixed 3.3V output at 1A from input voltages ranging 4.75V to 40V. This component operates at 52kHz switching frequency in a TO-263-6 D2PAK package with 5 leads plus tab. The part is currently listed as obsolete, making equivalent and substitute parts necessary for ongoing design support and production continuity. Active alternatives with identical or enhanced electrical characteristics are available from multiple manufacturers including Microchip Technology and Texas Instruments.

Key Parameters

Parameter	Value
Function	Step-Down (Buck)
Output Voltage	3.3V Fixed
Output Current	1A
Input Voltage Range	4.75V to 40V
Switching Frequency	52kHz
Package Type	TO-263-6, D2PAK (5 Leads + Tab)
Operating Temperature	-40°C to 125°C (TJ)
Mounting Type	Surface Mount
Synchronous Rectifier	No

Substitute Part Grouping Explanation

Substitution for the LM2575D2T-3.3R4 is determined by the following critical parameters: fixed 3.3V output voltage, buck topology, TO-263-6 D2PAK package compatibility, and operating temperature range of -40°C to 125°C. Parts are grouped into two categories:

Direct Equivalents (1A Output Current): Parts maintaining the exact 1A output current specification with identical package and voltage characteristics. These include the LM2575D2T-3.3R4G (onsemi, active status), LM2575-3.3WU (Microchip Technology), LM2591HVS-3.3/NOPB (Texas Instruments), and LM2591HVSX-3.3/NOPB (Texas Instruments). All operate at fixed 3.3V output with TO-263-6 packaging.

Higher Current Alternatives (3A Output Current): Parts with enhanced output current capability (3A) while maintaining the same 3.3V fixed output, TO-263-6 package, and operating temperature range. These include LM2576-3.3WU, LM2576-3.3WU-TR (Microchip Technology), LM2596S-3.3/NOPB, and LM2596SX-3.3/NOPB (Texas Instruments). These are suitable for designs requiring increased current headroom.

Multi-Function Alternative: The MIC4575-3.3WU and MIC4575-3.3WU-TR (Microchip Technology) provide buck and buck-boost topology with 1.7A switch current, offering design flexibility for applications requiring step-up capability alongside step-down regulation.

Parameter Comparison

Part Number	Manufacturer	Output Voltage	Output Current	Input Voltage Range	Switching Frequency	Package	Product Status	RoHS Status
LM2575D2T-3.3R4	onsemi	3.3V	1A	4.75V–40V	52kHz	TO-263-6, D2PAK-5	Obsolete	Non-compliant
LM2575D2T-3.3R4G	onsemi	3.3V	1A	4.75V–40V	52kHz	TO-263-6, D2PAK-5	Active	ROHS3 Compliant
LM2575-3.3WU	Microchip Technology	3.3V	1A	4V–40V	52kHz	TO-263-6, D2PAK-5	Active	ROHS3 Compliant
LM2576-3.3WU	Microchip Technology	3.3V	3A	4V–40V	52kHz	TO-263-6, D2PAK-5	Active	ROHS3 Compliant
LM2576-3.3WU-TR	Microchip Technology	3.3V	3A	4V–40V	52kHz	TO-263-6, D2PAK-5	Active	ROHS3 Compliant
LM2591HVS-3.3/NOPB	Texas Instruments	3.3V	1A	4.5V–60V	150kHz	TO-263-6, D2PAK-5	Active	ROHS3 Compliant
LM2591HVSX-3.3/NOPB	Texas Instruments	3.3V	1A	4.5V–60V	150kHz	TO-263-6, D2PAK-5	Active	ROHS3 Compliant
LM2596S-3.3/NOPB	Texas Instruments	3.3V	3A	4.5V–40V	150kHz	TO-263-6, D2PAK-5	Active	ROHS3 Compliant
LM2596SX-3.3/NOPB	Texas Instruments	3.3V	3A	4.5V–40V	150kHz	TO-263-6, D2PAK-5	Active	ROHS3 Compliant
MIC4575-3.3WU	Microchip Technology	3.3V	1.7A (Switch)	4V–24V	200kHz	TO-263-6, D2PAK-5	Active	ROHS3 Compliant
MIC4575-3.3WU-TR	Microchip Technology	3.3V	1.7A (Switch)	4V–24V	200kHz	TO-263-6, D2PAK-5	Active	ROHS3 Compliant

Engineering Selection Recommendations

For Direct Replacement (1A Applications): The LM2575D2T-3.3R4G is the primary direct substitute, offering identical electrical specifications with active product status and ROHS3 compliance. This part is recommended when the original design parameters must be maintained without modification.

For Active Product Continuity: LM2575-3.3WU (Microchip Technology) provides equivalent 1A output with active status and ROHS3 compliance. The minimum input voltage is 4V versus 4.75V on the original part, providing broader input range compatibility.

For Higher Current Designs: LM2576-3.3WU, LM2576-3.3WU-TR, LM2596S-3.3/NOPB, and LM2596SX-3.3/NOPB support 3A output current while maintaining 3.3V fixed output and TO-263-6 packaging. These are suitable for designs requiring increased current capacity without PCB redesign.

For Extended Input Voltage Range: LM2591HVS-3.3/NOPB and LM2591HVSX-3.3/NOPB (Texas Instruments) accept input voltages up to 60V compared to 40V maximum on the original part, with 1A output current and ROHS3 compliance. Switching frequency is 150kHz versus 52kHz.

For Multi-Topology Applications: MIC4575-3.3WU and MIC4575-3.3WU-TR provide buck and buck-boost capability with 1.7A switch current. Input voltage range is limited to 4V–24V. These are suitable only for designs where the reduced input voltage range is acceptable and multi-topology functionality is required.

All recommended substitutes maintain the TO-263-6 D2PAK package, surface mount configuration, and -40°C to 125°C operating temperature range, ensuring PCB compatibility without layout modifications.

Frequently Asked Questions (FAQ)

Q: Can LM2575D2T-3.3R4G be used as a direct replacement for LM2575D2T-3.3R4?

A: Yes. The LM2575D2T-3.3R4G is a direct equivalent with identical electrical specifications: 3.3V fixed output, 1A output current, 4.75V–40V input range, 52kHz switching frequency, and TO-263-6 D2PAK packaging. The primary difference is product status (active versus obsolete) and RoHS compliance (ROHS3 compliant versus non-compliant).

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

A: Output current rating determines maximum continuous load current the regulator can supply. The 1A parts (LM2575-3.3WU, LM2591HVS-3.3/NOPB) are suitable for designs drawing up to 1A at 3.3V. The 3A parts (LM2576-3.3WU, LM2596S-3.3/NOPB) support loads up to 3A. Higher current parts are backward compatible with lower current designs but require appropriate thermal management and PCB layout for the increased power dissipation.

Q: Are all substitute parts in the same package?

A: Yes. All listed substitutes use the TO-263-6 D2PAK package with 5 leads plus tab, ensuring identical PCB footprint and pin compatibility. Packaging variants (Tube, Cut Tape, Tape & Reel) refer to supply format only and do not affect electrical or mechanical compatibility.

Q: What is the significance of switching frequency differences?

A: The original LM2575D2T-3.3R4 operates at 52kHz. Texas Instruments parts (LM2591, LM2596 series) operate at 150kHz, and MIC4575 operates at 200kHz. Higher switching frequency reduces output filter component size but may increase EMI. Lower frequency reduces EMI but requires larger filter components. Frequency selection depends on application requirements for noise, component size, and thermal performance.

Q: Can MIC4575-3.3WU be used in place of LM2575D2T-3.3R4?

A: MIC4575-3.3WU provides 3.3V output with 1.7A switch current in the same TO-263-6 package. However, the input voltage range is limited to 4V–24V compared to 4.75V–40V on the original part. This part is suitable only if the application input voltage remains within 4V–24V. The buck-boost topology adds design flexibility but is not required for simple buck applications.

Q: What does ROHS3 compliance mean for substitution?

A: ROHS3 compliance indicates the part meets Restriction of Hazardous Substances Directive requirements, restricting lead, cadmium, mercury, and other hazardous materials. The original LM2575D2T-3.3R4 is non-compliant. All active substitutes listed are ROHS3 compliant, making them suitable for applications with environmental or regulatory requirements for hazardous substance restriction.

Q: Are there packaging format differences between substitute parts?

A: Yes. Packaging format refers to supply method: Tube (loose components in tube), Cut Tape (CT) & Digi-Reel (individual tape strips), and Tape & Reel (TR) (full reel). These affect ordering and handling but do not change electrical specifications or PCB compatibility. Select based on production volume and assembly equipment requirements.

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