LM4900MM/NOPB Equivalent & Substitute Parts

Part Overview

The LM4900MM/NOPB is a Class AB mono audio amplifier IC manufactured by Texas Instruments, part of the Boomer® series. This device delivers 675mW output power at 8Ω load in a compact 8-VSSOP surface mount package. The LM4900MM/NOPB is classified as obsolete, making equivalent and substitute parts necessary for new designs and production continuity. Substitute parts must maintain functional compatibility across Class AB amplification topology, mono output configuration, and thermal/protection feature sets while accommodating modern active product status and supply chain availability.

Substiute Parts

LM4900MM/NOPB

Texas InstrumentsIn Stock: 1011LM4900MM/NOPB Datasheet

Current PartRFQ

TPA741DGNR

Texas InstrumentsIn Stock: 18214TPA741DGNR Datasheet

MFR RecommendedRFQ

TPA751DGNR

Texas InstrumentsIn Stock: 95427TPA751DGNR Datasheet

MFR RecommendedRFQ

TPA741DGN

Texas InstrumentsIn Stock: 1241TPA741DGN Datasheet

MFR RecommendedRFQ

TPA751DGN

Texas InstrumentsIn Stock: 2272TPA751DGN Datasheet

MFR RecommendedRFQ

TS4990IST

STMicroelectronicsIn Stock: 36641TS4990IST Datasheet

MFR RecommendedRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution eligibility for the LM4900MM/NOPB is determined by the following critical parameters:

Primary Compatibility Criteria:

• Amplifier topology: Class AB
• Output configuration: 1-Channel (Mono)
• Supply voltage range: Must encompass or overlap with 2V ~ 5.5V
• Operating temperature range: -40°C ~ 85°C (TA)
• Mounting type: Surface Mount
• Package footprint: 8-pin VSSOP/MSOP/HVSSOP family (0.118", 3.00mm Width)

Secondary Compatibility Criteria:

• Protection features: Thermal protection (mandatory); Shutdown capability (required); Depop functionality (preferred)
• Regulatory compliance: ROHS3 Compliant; REACH Unaffected; MSL 1 rating
• Output power: Minimum 675mW @ 8Ω (equal or greater acceptable)

Five substitute parts meet these criteria across two manufacturer sources: Texas Instruments (TPA741/TPA751 series) and STMicroelectronics (TS4990IST). All substitutes are active products with superior or equivalent electrical specifications and enhanced feature sets compared to the obsolete LM4900MM/NOPB.

Parameter Comparison

Engineering Selection Recommendations

Texas Instruments TPA741/TPA751 Series (Preferred for Direct Replacement):

The TPA741DGNR and TPA751DGNR represent the primary substitutes for the LM4900MM/NOPB. Both devices are active products manufactured by the original equipment supplier, ensuring long-term availability and design continuity. The TPA741 and TPA751 series deliver 700mW output power at 8Ω, exceeding the original 675mW specification. Supply voltage range is 2.5V ~ 5.5V, which covers the upper portion of the LM4900MM/NOPB range (2V minimum is not supported; designs operating below 2.5V require alternative evaluation). Both series incorporate differential input stages, short-circuit protection, and thermal protection. The TPA741 retains depop functionality matching the original device; the TPA751 omits depop but provides equivalent protection architecture.

Packaging variants are available: TPA741DGNR and TPA751DGNR in Tape & Reel format for production volumes; TPA741DGN and TPA751DGN in Tube format for lower-volume applications. All variants use 8-HVSSOP packages with exposed thermal pads, improving heat dissipation compared to the original 8-VSSOP package. PCB layout modifications may be required to accommodate the exposed pad design.

STMicroelectronics TS4990IST (Alternative for Enhanced Performance):

The TS4990IST provides an alternative substitute with enhanced output power capability (1.2W @ 8Ω). This device supports a lower minimum supply voltage (2.2V vs. 2.5V), extending compatibility to designs requiring operation near 2V. The TS4990IST incorporates differential inputs, depop functionality, and thermal protection. Standby mode replaces shutdown functionality, providing equivalent power management. The 8-MiniSO package maintains the 0.118" (3.00mm) width standard but uses a different pin configuration; PCB redesign is required for this substitution.

Compliance & Regulatory Status:

All substitute parts maintain ROHS3 compliance, REACH unaffected status, and MSL 1 (unlimited) moisture sensitivity ratings, matching the original device specifications. No regulatory barriers exist for substitution in existing designs.

Inventory Availability:

TPA751DGNR shows the highest inventory level (95,400 pcs), followed by TS4990IST (36,573 pcs) and TPA741DGNR (18,144 pcs), ensuring supply chain continuity for production requirements.

Frequently Asked Questions (FAQ)

Q: Can the TPA741DGNR or TPA751DGNR be used as direct pin-for-pin replacements for the LM4900MM/NOPB?

A: The TPA741 and TPA751 series use 8-HVSSOP packages with exposed thermal pads, while the LM4900MM/NOPB uses 8-VSSOP packaging. Pin count and signal assignments are compatible, but the exposed pad design requires PCB layout modifications. Thermal pad connection to ground plane is necessary for optimal performance. Electrical functionality is compatible without circuit modifications.

Q: What is the minimum supply voltage requirement for substitute parts?

A: The TPA741DGNR, TPA751DGNR, TPA741DGN, and TPA751DGN operate from 2.5V minimum. The TS4990IST supports 2.2V minimum. The original LM4900MM/NOPB operates from 2V minimum. Designs requiring operation below 2.5V cannot use the TPA741/TPA751 series and must evaluate the TS4990IST or alternative solutions.

Q: Does the absence of depop functionality in the TPA751 series affect audio quality?

A: Depop is a protection feature that suppresses audible transients during power-on and shutdown events. The TPA751 series includes short-circuit and thermal protection but omits depop. The TPA741 series retains depop functionality. Selection depends on application requirements for transient suppression during power cycling.

Q: Are PCB layout changes required when substituting the TS4990IST?

A: Yes. The TS4990IST uses 8-MiniSO packaging with a different pin configuration than the LM4900MM/NOPB and TPA741/TPA751 series. Complete PCB redesign is required. The TS4990IST is suitable for new designs rather than direct replacement scenarios.

Q: What is the significance of the exposed thermal pad in TPA741/TPA751 packages?

A: The exposed thermal pad improves heat dissipation by providing a direct thermal path to the PCB ground plane. This design enhancement allows higher sustained output power and improved thermal stability compared to the original 8-VSSOP package. PCB layout must include a thermal via pattern connecting the exposed pad to internal ground planes for effective heat transfer.

Q: Can substitute parts be mixed in production inventory?

A: All substitute parts are functionally compatible and meet identical regulatory and compliance standards. However, mixing different package types (HVSSOP vs. MiniSO) requires separate PCB designs. Within the TPA741/TPA751 series, packaging format differences (Tape & Reel vs. Tube) do not affect electrical performance and can be managed through procurement logistics.

Q: What output power margin exists when substituting with TPA741/TPA751 series?

A: The TPA741 and TPA751 deliver 700mW at 8Ω, providing a 25mW (3.7%) power margin above the original 675mW specification. The TS4990IST delivers 1.2W, providing a 525mW (77.8%) power margin. Designs operating at maximum output power of the LM4900MM/NOPB will operate within safe thermal limits with either substitute.

Q: Are there feature differences between TPA741DGNR and TPA741DGN?

A: TPA741DGNR and TPA741DGN are electrically identical. The difference is packaging format: DGNR is supplied in Tape & Reel (TR) format for automated assembly; DGN is supplied in Tube format for manual handling or lower-volume applications. Select based on production assembly method and volume requirements.