TPA731DR Equivalent & Substitute Parts

Part Overview

The TPA731DR is a Class AB mono audio amplifier IC manufactured by Texas Instruments, housed in an 8-SOIC surface mount package. This device delivers 700mW output power at 8Ohm load with a supply voltage range of 2.5V to 5.5V. The TPA731DR features differential inputs, short-circuit and thermal protection, and shutdown functionality. The product is currently in Last Time Buy status, indicating end-of-life phase. Identifying equivalent and substitute parts is necessary to ensure design continuity and maintain component availability for ongoing production and support requirements.

Substiute Parts

TPA731DR

Texas InstrumentsIn Stock: 1702TPA731DR Datasheet

Current PartRFQ

LM4818MX/NOPB

Texas InstrumentsIn Stock: 1267LM4818MX/NOPB Datasheet

MFR RecommendedRFQ

LM4819MX/NOPB

Texas InstrumentsIn Stock: 9913LM4819MX/NOPB Datasheet

MFR RecommendedRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitute parts for the TPA731DR are identified based on the following critical parameters that determine functional compatibility:

Package Compatibility: All substitute parts must use the 8-SOIC surface mount package to ensure direct PCB layout compatibility without redesign.

Amplifier Classification: All parts must be Class AB mono audio amplifiers to maintain equivalent operational characteristics and audio quality performance.

Supply Voltage Range: Substitute parts must operate within or encompass the 2.5V to 5.5V supply voltage specification of the original part.

Output Power Capability: While substitute parts may have different output power ratings at specified load impedances, they must be suitable for the intended application load conditions.

Protection Features: Substitute parts must include thermal protection and shutdown functionality as baseline safety requirements.

Compliance Standards: All substitute parts must maintain ROHS3 compliance and equivalent regulatory certifications.

The two identified substitute parts, LM4818MX/NOPB and LM4819MX/NOPB, meet these substitution criteria while offering active product status and improved inventory availability.

Parameter Comparison

Engineering Selection Recommendations

For LM4819MX/NOPB: This part is the preferred substitute when differential input capability is required. The LM4819MX/NOPB maintains the differential input feature present in the TPA731DR while offering active product status and significantly higher inventory availability (9841 pieces in stock). The lower output power rating (350mW @ 16Ohm versus 700mW @ 8Ohm) must be evaluated against specific application load impedance requirements. The extended lower supply voltage limit (2V minimum) provides additional design flexibility.

For LM4818MX/NOPB: This part is suitable for applications where differential inputs are not required. The LM4818MX/NOPB offers active product status and maintains core amplifier functionality with thermal protection and shutdown features. Lower inventory availability (1165 pieces) compared to LM4819MX/NOPB should be considered for long-term supply planning.

Compliance Basis: Both substitute parts maintain ROHS3 compliance, REACH unaffected status, and identical EAR99 export classification as the original TPA731DR, ensuring regulatory continuity in design transitions.

Frequently Asked Questions (FAQ)

Q: Can LM4818MX/NOPB or LM4819MX/NOPB be used as direct pin-for-pin replacements for TPA731DR?

A: Both parts use the 8-SOIC package with identical physical dimensions (0.154", 3.90mm width), enabling direct PCB layout compatibility without redesign. Pin configuration compatibility must be verified against specific application schematics.

Q: What is the primary difference between LM4818MX/NOPB and LM4819MX/NOPB?

A: The LM4819MX/NOPB includes differential input capability, matching the TPA731DR feature set. The LM4818MX/NOPB does not include differential inputs. Both parts deliver identical output power specifications (350mW @ 16Ohm) and thermal protection.

Q: Why is the output power rating lower in the substitute parts?

A: The LM4818MX/NOPB and LM4819MX/NOPB are rated at 350mW @ 16Ohm load impedance, while the TPA731DR is rated at 700mW @ 8Ohm. Output power delivery is load-dependent. Application compatibility depends on the actual load impedance and power requirements of the target circuit.

Q: Are there supply voltage compatibility concerns?

A: The substitute parts operate at 2V minimum supply voltage compared to 2.5V for the TPA731DR. Both support the full 5.5V upper limit. Applications operating at 2V to 2.5V range will function with substitutes but not with the original TPA731DR.

Q: What is the significance of the TPA731DR being in Last Time Buy status?

A: Last Time Buy status indicates the manufacturer is discontinuing this product. Existing inventory will be depleted without replenishment. Transitioning to active substitute parts (LM4818MX/NOPB or LM4819MX/NOPB) ensures long-term component availability and supply chain continuity.

Q: How should packaging format affect the selection between LM4818MX/NOPB and LM4819MX/NOPB?

A: Both substitute parts are available in Cut Tape (CT) and Digi-Reel® packaging formats. The TPA731DR is supplied in Tape & Reel (TR) format. Packaging selection should align with production equipment capabilities and volume requirements rather than substitution compatibility.

Q: Are there feature differences that would prevent substitution in specific applications?

A: The LM4818MX/NOPB lacks differential input capability present in both TPA731DR and LM4819MX/NOPB. Applications requiring differential input signal processing must use LM4819MX/NOPB. Both substitute parts include depop functionality not explicitly listed for TPA731DR.