LM2575-3.3BU Equivalent & Substitute Parts

Part Overview

The LM2575-3.3BU is a buck switching regulator IC from Microchip Technology designed for positive fixed 3.3V output at 1A current capacity. This device operates across a 4V to 40V input range with a 52kHz switching frequency and is housed in a TO-263-6 (D2PAK) surface mount package. The LM2575-3.3BU is classified as obsolete, making equivalent and substitute parts necessary for new designs and ongoing production requirements. Substitute parts must maintain compatibility across input voltage range, output voltage specification, package form factor, and thermal operating range while meeting current application demands.

Key Parameters

Parameter	LM2575-3.3BU
Manufacturer	Microchip Technology
Function	Step-Down (Buck)
Output Voltage	3.3V Fixed
Output Current	1A
Input Voltage Range	4V to 40V
Switching Frequency	52kHz
Package	TO-263-6 (D2PAK, 5 Leads + Tab)
Operating Temperature	-40°C to 125°C (TJ)
Product Status	Obsolete
RoHS Status	RoHS Non-Compliant

Substitute Part Grouping Explanation

Substitution logic for the LM2575-3.3BU is based on the following critical parameters:

Direct Compatibility Parameters:

Output voltage: 3.3V fixed
Package form factor: TO-263-6 (D2PAK)
Operating temperature range: -40°C to 125°C
Output configuration: Positive
Topology: Buck
Mounting type: Surface mount

Allowable Variation Parameters:

Output current: Equal or greater than 1A
Input voltage range: Must encompass minimum 4V and maximum 40V
Switching frequency: May vary (52kHz or higher acceptable)
Product status: Active preferred over obsolete
RoHS compliance: ROHS3 compliant preferred

Substitute parts are grouped into two categories: direct pin-compatible replacements maintaining 1A output current specification, and higher-current alternatives providing enhanced performance headroom while maintaining identical package and voltage specifications.

Parameter Comparison

Parameter	LM2575-3.3BU	LM2575-3.3WU	TL2575-33IKTTR	LM2592HVS-3.3/NOPB	LM2592HVSX-3.3/NOPB	LM2596S-3.3/NOPB	LM2596SX-3.3/NOPB
Manufacturer	Microchip	Microchip	Texas Instruments	Texas Instruments	Texas Instruments	Texas Instruments	Texas Instruments
Output Voltage	3.3V	3.3V	3.3V	3.3V	3.3V	3.3V	3.3V
Output Current	1A	1A	1A	2A	2A	3A	3A
Input Voltage (Min)	4V	4V	4.75V	4.5V	4.5V	4.5V	4.5V
Input Voltage (Max)	40V	40V	40V	60V	60V	40V	40V
Switching Frequency	52kHz	52kHz	52kHz	150kHz	150kHz	150kHz	150kHz
Package	TO-263-6	TO-263-6	TO-263	TO-263-6	TO-263-6	TO-263-6	TO-263-6
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	-40°C to 125°C
Product Status	Obsolete	Active	Active	Active	Active	Active	Active
RoHS Status	Non-Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant

Engineering Selection Recommendations

Primary Direct Replacement: LM2575-3.3WU from Microchip Technology is the direct equivalent to LM2575-3.3BU. This part maintains identical electrical specifications (1A output, 52kHz switching frequency, 4V to 40V input range) and package form factor while offering active product status and ROHS3 compliance. The LM2575-3.3WU is available in tube packaging with 25,300 units in stock, providing supply continuity for existing designs.

Pin-Compatible Alternative: TL2575-33IKTTR from Texas Instruments provides pin-compatible substitution with identical 1A output current and 52kHz switching frequency. Input voltage minimum is specified at 4.75V (versus 4V for the original), which may require design verification for applications operating below 4.75V. This part is active, ROHS3 compliant, and available in tape and reel packaging.

Higher-Current Alternatives: LM2592HVS-3.3/NOPB and LM2592HVSX-3.3/NOPB (2A output) and LM2596S-3.3/NOPB and LM2596SX-3.3/NOPB (3A output) provide enhanced current capacity while maintaining 3.3V output voltage and TO-263-6 package compatibility. These parts operate at 150kHz switching frequency and support input voltage up to 60V (LM2592 series) or 40V (LM2596 series). All are active, ROHS3 compliant, and suitable for designs requiring additional current headroom.

Frequently Asked Questions (FAQ)

Q: Can LM2575-3.3WU be used as a direct drop-in replacement for LM2575-3.3BU? A: Yes. LM2575-3.3WU maintains identical electrical specifications, package form factor, and pin configuration. The primary difference is product status (active versus obsolete) and RoHS compliance (ROHS3 versus non-compliant).

Q: What is the minimum input voltage difference between TL2575-33IKTTR and the original LM2575-3.3BU? A: TL2575-33IKTTR specifies a minimum input voltage of 4.75V, compared to 4V for LM2575-3.3BU. Applications requiring operation below 4.75V must use LM2575-3.3WU or verify TL2575-33IKTTR performance at the lower voltage.

Q: Are the higher-current parts (LM2592 and LM2596 series) pin-compatible with LM2575-3.3BU? A: Yes. All substitute parts use the TO-263-6 (D2PAK) package with identical pin assignments. Higher-current parts can be used in applications designed for 1A output without modification, providing additional performance margin.

Q: What is the impact of switching frequency differences between 52kHz and 150kHz? A: Higher switching frequency (150kHz in LM2592 and LM2596 series) allows for smaller external filter components and reduced output ripple. This is a performance enhancement with no negative impact on compatibility. Existing PCB designs may benefit from component size reduction if redesigned.

Q: Which substitute part offers the best supply availability? A: LM2596SX-3.3/NOPB provides the highest inventory level at 25,400 units in stock. LM2575-3.3WU offers 25,300 units. Both parts ensure long-term supply continuity.

Q: Are all substitute parts ROHS3 compliant? A: Yes. All active substitute parts listed (LM2575-3.3WU, TL2575-33IKTTR, LM2592HVS-3.3/NOPB, LM2592HVSX-3.3/NOPB, LM2596S-3.3/NOPB, LM2596SX-3.3/NOPB) are ROHS3 compliant. The original LM2575-3.3BU is RoHS non-compliant.

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