LM5642XMH Buck Regulator Controller IC Equivalent & Substitute Parts

Part Overview

The LM5642XMH is a buck regulator positive output step-down DC-DC controller IC manufactured by Texas Instruments in a 28-PowerTSSOP package. This device functions as a transistor driver for two-phase synchronous buck conversion with integrated current limiting, enable control, and soft-start features. The main part number LM5642XMH is classified as obsolete, making identification of active equivalent and substitute parts essential for ongoing design support and procurement.

Substiute Parts

LM5642XMH

Texas InstrumentsIn Stock: 5002LM5642XMH Datasheet

Current PartRFQ

LM5642XMH/NOPB

Texas InstrumentsIn Stock: 1444LM5642XMH/NOPB Datasheet

DirectRFQ

LM5642MH/NOPB

Texas InstrumentsIn Stock: 1295LM5642MH/NOPB Datasheet

Parametric EquivalentRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution of the LM5642XMH is determined by strict equivalence across the following critical parameters:

• Functional topology: Buck regulator controller with two-phase output
• Output configuration: Positive output, transistor driver type
• Supply voltage range: 4.5V ~ 36V
• Control features: Current limit, enable, soft start
• Package compatibility: 28-PowerTSSOP form factor
• Operating temperature: -40°C ~ 125°C

The substitute parts are grouped into two categories:

Direct Manufacturer Equivalent (LM5642XMH/NOPB): Identical part number with NOPB (No Lead/Pb-free) designation, differing only in packaging format (Tube) and product status (Active vs. Obsolete). All electrical and thermal parameters remain unchanged.

Parametric Equivalent (LM5642MH/NOPB): Same base product family with identical package, supply voltage, output configuration, and control features. The switching frequency differs (200kHz vs. 375kHz), which affects application-specific performance but maintains functional compatibility for buck regulation topology.

Parameter Comparison

Engineering Selection Recommendations

LM5642XMH/NOPB is the primary substitute for obsolete LM5642XMH. This part maintains identical electrical specifications and package form factor while offering active product status and ROHS3 compliance. The NOPB designation indicates lead-free construction, meeting modern environmental and regulatory requirements. This substitute is recommended for direct replacement in existing designs without circuit modification.

LM5642MH/NOPB serves as a parametric equivalent when switching frequency variation is acceptable within the application design. The reduced switching frequency (200kHz vs. 375kHz) affects output filter component sizing and electromagnetic interference characteristics but maintains functional buck regulation capability. This part is suitable for applications where lower switching frequency provides design advantages such as reduced EMI or simplified filtering requirements. ROHS3 compliance and active product status apply to this variant as well.

Both substitute parts carry identical supply voltage range, output configuration, control features, and thermal operating range, ensuring functional compatibility within the LM5642 controller family.

Frequently Asked Questions (FAQ)

Q: Can LM5642XMH/NOPB directly replace LM5642XMH in existing PCB designs?

A: Yes. LM5642XMH/NOPB is a direct equivalent with identical electrical parameters, package dimensions, and pin configuration. No circuit modifications are required. The primary differences are product status (Active vs. Obsolete) and RoHS compliance (ROHS3 vs. Non-Compliant).

Q: What is the significance of the switching frequency difference between LM5642XMH/NOPB (375kHz) and LM5642MH/NOPB (200kHz)?

A: Switching frequency affects the size and cost of output filter components (inductors and capacitors). Higher frequency (375kHz) allows smaller passive components; lower frequency (200kHz) requires larger components but may reduce electromagnetic interference. Circuit design must account for this parameter when selecting the parametric equivalent.

Q: Are all three parts pin-compatible?

A: Yes. All three parts use the 28-PowerTSSOP package with identical pin assignments and functionality. Physical PCB layout compatibility is maintained across all variants.

Q: What does NOPB designation mean?

A: NOPB indicates "No Lead/Pb-free" construction. This designation confirms the part meets lead-free soldering requirements and RoHS compliance standards, eliminating lead (Pb) from the component manufacturing process.

Q: Why is the original LM5642XMH classified as obsolete?

A: Product obsolescence typically results from manufacturer discontinuation decisions. Active equivalents (LM5642XMH/NOPB and LM5642MH/NOPB) are available from Texas Instruments to support ongoing applications and new designs.

Q: Can LM5642MH/NOPB be used as a drop-in replacement for LM5642XMH?

A: LM5642MH/NOPB is functionally compatible but requires circuit design review due to the 200kHz switching frequency. Output filter component values must be recalculated for the lower frequency. This is not a true drop-in replacement without design modification.

Q: What is the moisture sensitivity level (MSL) and why is it relevant?

A: MSL 1 (Unlimited) indicates the component has no moisture sensitivity restrictions. These parts can be stored indefinitely without special humidity control, simplifying inventory management and reducing handling costs.