LA5756-MDB-E Equivalent & Substitute Parts

Part Overview

The LA5756-MDB-E is a buck switching regulator IC manufactured by onsemi, designed for step-down voltage conversion applications. It delivers 4.2A output current with adjustable positive output voltage ranging from 1.26V to 32V, operating from a 4.5V to 32V input supply. The device is packaged in TO-220-5 Formed Leads configuration for through-hole mounting.

This part is classified as obsolete. Identifying equivalent and substitute components is necessary to maintain design continuity, ensure supply chain availability, and support ongoing production or maintenance requirements for systems utilizing this regulator.

Substiute Parts

LA5756-MDB-E

onsemiIn Stock: 2379LA5756-MDB-E Datasheet

Current PartRFQ

MC33167TG

onsemiIn Stock: 6746MC33167TG Datasheet

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Key Parameters

Substitute Part Grouping Explanation

Substitution of the LA5756-MDB-E is evaluated based on the following critical parameters:

• Input voltage range compatibility (minimum 4.5V, maximum 32V)
• Output voltage adjustability range (minimum 1.26V, maximum 32V)
• Output current capability (4.2A or greater)
• Package type (TO-220-5 configuration for mechanical and thermal compatibility)
• Topology (buck or buck-boost capable of step-down operation)
• Switching frequency stability (80kHz reference)
• Operating temperature range coverage

The MC33167TG qualifies as a substitute because it operates within compatible input and output voltage ranges, provides equal or greater output current capacity (5.5A), maintains the same package configuration (TO-220-5), and supports adjustable positive output voltage operation. While the MC33167TG offers additional boost capability and operates at a different switching frequency (72kHz), these differences do not prevent its use in applications requiring buck regulation with the specified electrical parameters.

Parameter Comparison

Engineering Selection Recommendations

Both the LA5756-MDB-E and MC33167TG are classified as obsolete products. Selection between these components should be based on application-specific requirements and supply chain availability.

The MC33167TG provides higher output current capacity (5.5A versus 4.2A) and extended maximum input voltage rating (40V versus 32V). However, the MC33167TG has a higher minimum input voltage requirement (7.5V versus 4.5V) and a higher minimum output voltage floor (5.05V versus 1.26V), which may limit its applicability in low-voltage output applications.

Both devices share identical REACH compliance status (REACH Unaffected) and export classification (EAR99). The MC33167TG carries RoHS3 compliance certification, whereas the LA5756-MDB-E compliance status is not specified in available documentation.

Frequently Asked Questions (FAQ)

Q: Can the MC33167TG directly replace the LA5756-MDB-E in all applications?

A: Direct substitution requires verification of three critical parameters: (1) minimum input voltage must not fall below 7.5V for the MC33167TG, whereas the LA5756-MDB-E operates from 4.5V; (2) minimum output voltage must be 5.05V or higher for the MC33167TG, whereas the LA5756-MDB-E supports output voltages as low as 1.26V; (3) PCB layout and thermal management may require adjustment due to different switching frequencies (72kHz versus 80kHz).

Q: Are there package compatibility concerns?

A: Both devices use TO-220-5 through-hole packages. The LA5756-MDB-E specifies "Formed Leads" while the MC33167TG uses standard TO-220-5 configuration. Pin assignments and lead spacing are compatible for direct PCB mounting without modification.

Q: What is the significance of the MC33167TG's boost capability?

A: The MC33167TG supports both buck and boost topologies, providing design flexibility beyond the LA5756-MDB-E's buck-only operation. In buck mode applications, this additional capability does not affect performance and does not require circuit modifications.

Q: How do switching frequency differences impact circuit design?

A: The LA5756-MDB-E operates at 80kHz while the MC33167TG operates at 72kHz. This 8kHz difference may require recalculation of output filter component values (inductors and capacitors) to maintain equivalent ripple voltage and current characteristics. Existing filter designs may require optimization for the substitute device.

Q: Are both devices suitable for new designs?

A: Both the LA5756-MDB-E and MC33167TG are classified as obsolete. Neither device is recommended for new design implementations. Current-generation alternatives from onsemi or other manufacturers should be evaluated for new applications requiring buck regulation functionality.