LA5771MP-E Equivalent & Substitute Parts

Part Overview

The LA5771MP-E is a buck switching regulator IC manufactured by onsemi, designed to deliver 3.3V fixed output at 3.1A from input voltages ranging from 5.5V to 28V. This device operates at 160kHz switching frequency and is packaged in TO-252-6 DPAK format with 5 leads plus tab. The LA5771MP-E is currently obsolete, making equivalent substitute parts necessary for new designs and production continuity. Suitable alternatives must maintain the same output voltage, topology, and current handling capability while accommodating the available packaging options.

Substiute Parts

LA5771MP-E

onsemiIn Stock: 1037LA5771MP-E Datasheet

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LM2575-3.3WU

Microchip TechnologyIn Stock: 25332LM2575-3.3WU Datasheet

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LM2575-3.3WU-TR

Microchip TechnologyIn Stock: 1820LM2575-3.3WU-TR Datasheet

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LM2576-3.3WU

Microchip TechnologyIn Stock: 1261LM2576-3.3WU Datasheet

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LM2576-3.3WU-TR

Microchip TechnologyIn Stock: 3580LM2576-3.3WU-TR Datasheet

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MIC4575-3.3WU

Microchip TechnologyIn Stock: 4000MIC4575-3.3WU Datasheet

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MIC4575-3.3WU-TR

Microchip TechnologyIn Stock: 707MIC4575-3.3WU-TR Datasheet

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MIC4576-3.3WU

Microchip TechnologyIn Stock: 4001MIC4576-3.3WU Datasheet

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MIC4576-3.3WU-TR

Microchip TechnologyIn Stock: 3498MIC4576-3.3WU-TR Datasheet

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Key Parameters

Substitute Part Grouping Explanation

Substitution for the LA5771MP-E is based on the following critical parameters:

• Output voltage fixed at 3.3V
• Buck topology (step-down conversion)
• Output current capability at or above 3.1A
• Input voltage range compatibility (minimum 4V to maximum 28V or higher)
• Surface mount packaging in TO-263 or equivalent form factor
• Active product status for ongoing availability

The substitute parts are grouped into two categories based on current output capability:

Category 1: 3A Output Current (Closest Match)

• LM2576-3.3WU and LM2576-3.3WU-TR deliver 3A output current, matching the LA5771MP-E performance envelope
• MIC4576-3.3WU and MIC4576-3.3WU-TR also provide 3A output current with enhanced input voltage range (up to 36V)

Category 2: Lower Current Output (1A to 1.7A)

• LM2575-3.3WU and LM2575-3.3WU-TR deliver 1A output current
• MIC4575-3.3WU and MIC4575-3.3WU-TR deliver 1.7A output current with buck-boost topology capability

Parameter Comparison

Engineering Selection Recommendations

Primary Substitutes (Recommended for Direct Replacement)

LM2576-3.3WU and LM2576-3.3WU-TR are the most suitable direct replacements. Both deliver 3A output current, matching the LA5771MP-E performance specification. These parts are manufactured by Microchip Technology with active product status, ensuring long-term availability. The extended input voltage range (4V to 40V) provides greater design flexibility than the original 5.5V to 28V specification. Both variants are RoHS3 compliant and REACH unaffected. The tape & reel variant (LM2576-3.3WU-TR) is preferred for high-volume production.

Alternative Substitutes (Higher Performance)

MIC4576-3.3WU and MIC4576-3.3WU-TR deliver 3A output current with enhanced switching frequency (200kHz versus 160kHz) and extended input voltage range (4V to 36V). These parts offer improved performance characteristics while maintaining active product status and RoHS3 compliance. The higher switching frequency enables smaller external component sizing. The tape & reel variant (MIC4576-3.3WU-TR) is suitable for automated assembly.

Lower Current Alternatives (Current-Limited Applications)

LM2575-3.3WU and LM2575-3.3WU-TR deliver 1A output current, suitable only for applications where load current does not exceed 1A. MIC4575-3.3WU and MIC4575-3.3WU-TR deliver 1.7A output current with buck-boost topology capability, providing additional design flexibility for applications requiring step-up conversion. These lower-current variants are not suitable for direct replacement in designs requiring the full 3.1A output capability.

Frequently Asked Questions (FAQ)

Q: Can LM2576-3.3WU directly replace LA5771MP-E without PCB redesign?

A: The LM2576-3.3WU uses TO-263-6 D2PAK packaging versus the LA5771MP-E TO-252-6 DPAK packaging. While both are surface mount packages with 5 leads plus tab, the pinout and physical dimensions differ. PCB layout modification is required. Verify pinout compatibility before implementation.

Q: What is the difference between tube and tape & reel packaging?

A: Tube packaging (LM2576-3.3WU) is suitable for manual assembly and small-volume production. Tape & reel packaging (LM2576-3.3WU-TR) is designed for automated pick-and-place assembly and high-volume manufacturing. Both contain identical die and electrical specifications.

Q: Why does MIC4576-3.3WU have a lower maximum operating temperature than LM2576-3.3WU?

A: MIC4576-3.3WU operates to 85°C (TA) while LM2576-3.3WU operates to 125°C (TJ). This reflects different thermal specifications and package thermal characteristics. For applications requiring operation above 85°C ambient, LM2576-3.3WU is the appropriate selection.

Q: Can MIC4575-3.3WU substitute for LA5771MP-E in a 3.1A application?

A: MIC4575-3.3WU delivers 1.7A output current, which is insufficient for applications requiring 3.1A. This part is not suitable for direct replacement in current-limited designs. Use LM2576-3.3WU or MIC4576-3.3WU for full current capability.

Q: What is the significance of the switching frequency difference between LA5771MP-E (160kHz) and substitute parts (52kHz to 200kHz)?

A: Switching frequency affects external component sizing and electromagnetic interference characteristics. Lower frequencies (52kHz) require larger inductors and capacitors but generate less EMI. Higher frequencies (200kHz) enable smaller components but increase switching losses. Component selection must account for the actual switching frequency of the chosen substitute.

Q: Are all substitute parts RoHS3 compliant?

A: Yes. All Microchip Technology substitute parts listed are RoHS3 compliant and REACH unaffected, meeting current environmental and regulatory requirements.