LM2647LQ Equivalent & Substitute Parts

Part Overview

The LM2647LQ is a buck regulator positive output step-down DC-DC controller IC manufactured by Texas Instruments in a 28-WQFN (5x5) package. This dual synchronous buck regulator is designed for applications requiring efficient step-down voltage conversion with integrated control features including current limiting, enable control, frequency adjustment, power good monitoring, and soft start functionality. The product is currently classified as obsolete, making identification of compatible substitute parts essential for ongoing system support and new design implementations.

Substiute Parts

LM2647LQ

Texas InstrumentsIn Stock: 2219LM2647LQ Datasheet

Current PartRFQ

LM2647LQ/NOPB

National SemiconductorIn Stock: 1903LM2647LQ/NOPB Datasheet

DirectRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitute parts for the LM2647LQ are identified based on strict electrical and mechanical parameter matching. The following criteria determine substitution eligibility:

Critical Matching Parameters:

• Output topology: Step-down buck regulator with positive output configuration
• Number of outputs and phases: Dual output, 2-phase operation
• Supply voltage range: 5.5V ~ 28V input capability
• Switching frequency range: 200kHz ~ 500kHz operation
• Duty cycle maximum: 75%
• Synchronous rectifier: Integrated synchronous rectification
• Control feature set: Current limit, enable, frequency control, power good, soft start
• Operating temperature range: -5°C ~ 125°C
• Package specification: 28-WQFN with exposed pad, 5x5mm footprint
• Mounting technology: Surface mount compatibility

The LM2647LQ/NOPB qualifies as a direct substitute based on complete alignment across all electrical specifications and mechanical packaging requirements.

Parameter Comparison

Engineering Selection Recommendations

The LM2647LQ/NOPB is a direct functional and mechanical equivalent to the LM2647LQ. Both parts share identical electrical specifications across all critical parameters including supply voltage range, switching frequency capability, duty cycle limits, and control feature implementation. The physical package footprint remains consistent at 28-WQFN (5x5mm) with exposed pad configuration, ensuring PCB layout compatibility without redesign.

A significant advantage of the LM2647LQ/NOPB is its active product status, contrasting with the obsolete classification of the original LM2647LQ. This status difference provides improved long-term availability and supply chain reliability for new designs and production continuity.

Both parts carry identical export classification (ECCN: EAR99) and tariff codes (HTSUS: 8542.39.0001), indicating no regulatory or compliance barriers to substitution. The transition from Texas Instruments to National Semiconductor sourcing does not introduce electrical or mechanical incompatibilities.

Frequently Asked Questions (FAQ)

Q: Can the LM2647LQ/NOPB be used as a direct replacement for the LM2647LQ in existing designs?

A: Yes. The LM2647LQ/NOPB provides identical electrical performance and mechanical compatibility. The 28-WQFN (5x5) package footprint, pin configuration, and functional specifications are equivalent, allowing direct PCB substitution without circuit modification.

Q: What does the "/NOPB" suffix indicate in the part number LM2647LQ/NOPB?

A: The "/NOPB" suffix indicates "No Plumbum" (lead-free) packaging. This designation specifies the lead-free solder finish on the component leads, distinguishing it from leaded versions while maintaining identical electrical and mechanical specifications.

Q: Why is the original LM2647LQ classified as obsolete?

A: Product obsolescence typically results from manufacturer discontinuation decisions based on market demand, technology evolution, or product line consolidation. The availability of the functionally equivalent LM2647LQ/NOPB with active status provides a viable path for ongoing system support.

Q: Are there any differences in control features between the LM2647LQ and LM2647LQ/NOPB?

A: No. Both parts implement identical control features: current limit, enable control, frequency adjustment, power good output, and soft start functionality. The feature set and operational behavior are equivalent.

Q: What is the significance of the 28-WQFN package specification?

A: The 28-WQFN (5x5mm) package is a quad flat no-lead surface mount package with 28 pins and an exposed thermal pad. This package type is standard for power management ICs requiring efficient thermal dissipation. The "W" designation indicates the 5x5mm body size. Both substitute parts use this identical package specification.

Q: Can the LM2647LQ/NOPB operate across the same temperature range as the original part?

A: Yes. Both parts operate across the identical temperature range of -5°C to 125°C junction temperature (TJ), ensuring equivalent thermal performance characteristics in target applications.

Q: What supply voltage range does the LM2647LQ/NOPB support?

A: The LM2647LQ/NOPB accepts input supply voltages from 5.5V to 28V, matching the original LM2647LQ specification. This range supports diverse industrial and automotive power distribution architectures.