LM4905LDX Equivalent & Substitute Parts

Part Overview

The LM4905LDX is a Class AB mono audio amplifier IC manufactured by Texas Instruments, part of the Boomer® series. This device delivers 1.07W output power at 8Ω load in a compact 8-WSON (3x3) surface mount package. The LM4905LDX is classified as obsolete, necessitating identification of active equivalent parts for new designs and production continuity. Substitute parts must maintain functional compatibility across audio amplification applications while meeting current supply chain requirements.

Substiute Parts

LM4905LDX

Texas InstrumentsIn Stock: 34712LM4905LDX Datasheet

Current PartRFQ

LM4923LQ/NOPB

Texas InstrumentsIn Stock: 3502LM4923LQ/NOPB Datasheet

MFR RecommendedRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution of the LM4905LDX is determined by the following critical parameters:

Functional Equivalence Criteria:

• Amplifier type: Class AB mono configuration
• Output power capability: minimum 1.07W at 8Ω load
• Supply voltage compatibility: overlapping range with 2.2V ~ 5.5V
• Operating temperature range: -40°C ~ 85°C
• Core protection features: thermal protection and shutdown capability
• Surface mount technology with exposed pad design

Regulatory & Compliance Alignment:

• RoHS3 compliance status
• REACH unaffected classification
• ECCN EAR99 export control category
• HTSUS commodity code 8542.33.0001

The LM4923LQ/NOPB qualifies as a manufacturer-recommended substitute based on matching functional architecture, enhanced feature set, active product status, and maintained compliance certifications. Package geometry differences require PCB layout evaluation but do not preclude electrical substitution.

Parameter Comparison

Engineering Selection Recommendations

Primary Substitute: LM4923LQ/NOPB

The LM4923LQ/NOPB is the manufacturer-recommended substitute for the obsolete LM4905LDX. Selection is justified on the following engineering grounds:

Product Status & Supply Continuity: The LM4923LQ/NOPB maintains active production status with current inventory availability (3456 pcs), ensuring long-term supply chain reliability compared to the obsolete LM4905LDX.

Electrical Compatibility: Output power specification of 1.1W at 8Ω exceeds the original 1.07W requirement, providing performance margin. Supply voltage range of 2.4V ~ 5.5V encompasses the primary operating window of the original part, with the lower limit adjustment (2.4V vs. 2.2V) representing a minor constraint in ultra-low-voltage applications.

Regulatory & Compliance Alignment: Both parts maintain identical RoHS3 compliance, REACH unaffected status, EAR99 export classification, and HTSUS commodity coding, eliminating compliance-related substitution barriers.

Feature Enhancement: The LM4923LQ/NOPB incorporates differential input capability in addition to the core depop, shutdown, and thermal protection features present in the original part. This enhancement expands application flexibility without introducing incompatibility.

Package Consideration: The transition from 8-WSON (3x3) to 8-WQFN (2x2) requires PCB layout modification. Pin-to-pin functional mapping must be verified against application schematics. The smaller footprint may provide board space optimization benefits.

Frequently Asked Questions (FAQ)

Q1: Can the LM4923LQ/NOPB directly replace the LM4905LDX without PCB modification?

A: Electrical substitution is valid; however, package geometry differs (8-WQFN 2x2 vs. 8-WSON 3x3). PCB footprint redesign is required. Pin functionality mapping must be confirmed against the respective datasheets to ensure correct signal routing.

Q2: What is the impact of the supply voltage range difference (2.2V vs. 2.4V minimum)?

A: The LM4923LQ/NOPB minimum supply voltage of 2.4V is 0.2V higher than the LM4905LDX specification. Applications operating below 2.4V require design review. Most battery-powered and USB-powered applications operate within the 2.4V ~ 5.5V range and are unaffected.

Q3: Does the additional differential input feature on the LM4923LQ/NOPB affect compatibility?

A: The differential input capability is an enhancement that does not compromise single-ended input operation. Existing single-ended input configurations remain fully compatible. The feature provides design flexibility for future applications requiring differential signal processing.

Q4: What is the significance of the MSL rating difference (1 vs. 3)?

A: MSL 1 (unlimited) on the LM4905LDX indicates no moisture sensitivity constraints. MSL 3 (168 hours) on the LM4923LQ/NOPB requires standard moisture control during storage and handling per IPC-A-610 guidelines. Standard manufacturing and assembly practices accommodate this requirement.

Q5: Are there any export or regulatory restrictions affecting substitution?

A: Both parts carry identical EAR99 export classification and HTSUS commodity coding. No additional regulatory barriers exist for the substitution. RoHS3 and REACH compliance status remains consistent.

Q6: What inventory considerations apply to this substitution?

A: The LM4905LDX is obsolete with limited remaining stock (34650 pcs reported). The LM4923LQ/NOPB is actively manufactured with current inventory (3456 pcs). Long-term design transitions should prioritize the active part to ensure supply continuity beyond current stock depletion.