TS421IDT Equivalent & Substitute Parts

Part Overview

The TS421IDT is a Class AB mono audio power amplifier IC manufactured by STMicroelectronics in an 8-SOIC surface mount package. This device delivers 367mW output power at 16Ohm load and operates across a 2V to 5.5V supply voltage range. The TS421IDT is classified as obsolete, making identification of equivalent and substitute parts essential for ongoing design support, production continuity, and component sourcing.

Substiute Parts

TS421IDT

STMicroelectronicsIn Stock: 1091TS421IDT Datasheet

Current PartRFQ

LM4889MA/NOPB

National SemiconductorIn Stock: 1301LM4889MA/NOPB Datasheet

SimilarRFQ

LM4889MAX/NOPB

Texas InstrumentsIn Stock: 32130LM4889MAX/NOPB Datasheet

SimilarRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution of the TS421IDT is determined by the following critical parameters:

Electrical Compatibility Criteria:

• Amplifier topology: Class AB mono configuration
• Single-channel (mono) output architecture
• Supply voltage range: 2V to 5.5V minimum overlap
• Operating temperature range: -40°C to 85°C
• Surface mount packaging: 8-SOIC form factor with identical 0.154" (3.90mm) width

Mechanical Compatibility Criteria:

• Package type: 8-SOIC (0.154", 3.90mm Width)
• Mounting type: Surface Mount

Regulatory Compliance:

• RoHS3 compliance
• ECCN: EAR99
• HTSUS: 8542.33.0001

The LM4889MA/NOPB and LM4889MAX/NOPB both satisfy these substitution criteria. Both devices are Class AB mono amplifiers in 8-SOIC packages with compatible supply voltage ranges and operating temperatures. The LM4889 series delivers higher output power (1W at 8Ohm) compared to the TS421IDT (367mW at 16Ohm), providing enhanced performance headroom for applications requiring the TS421IDT.

Parameter Comparison

Engineering Selection Recommendations

LM4889MAX/NOPB (Texas Instruments) - Primary Substitute

The LM4889MAX/NOPB is the recommended primary substitute for the obsolete TS421IDT. This device is currently in active production status with 32,044 units in stock. It maintains full electrical and mechanical compatibility through identical 8-SOIC packaging, matching operating temperature range (-40°C to 85°C), and overlapping supply voltage specifications (2.2V to 5.5V). The LM4889MAX/NOPB carries ROHS3 compliance and EAR99 classification, aligning with the original part's regulatory requirements. The higher output power specification (1W at 8Ohm versus 367mW at 16Ohm) provides performance margin for applications originally designed around the TS421IDT.

LM4889MA/NOPB (National Semiconductor) - Secondary Substitute

The LM4889MA/NOPB serves as a secondary substitute option. This device shares identical electrical topology, package form factor, and operating parameters with the LM4889MAX/NOPB. It is currently in active production with 1,245 units in stock. The supply voltage range (2.2V to 5.5V) and operating temperature specifications match the primary substitute. Selection between LM4889MA/NOPB and LM4889MAX/NOPB should be based on availability, lead time, and supply chain requirements, as both devices are functionally equivalent for TS421IDT replacement applications.

Frequently Asked Questions (FAQ)

Q: Can the LM4889MAX/NOPB directly replace the TS421IDT without PCB modifications?

A: Yes. Both devices use identical 8-SOIC (0.154", 3.90mm Width) packaging and surface mount configuration. Pin-to-pin compatibility and footprint alignment are maintained. No PCB layout changes are required for mechanical or electrical integration.

Q: What is the significance of the higher output power rating on the LM4889 series?

A: The LM4889 series delivers 1W at 8Ohm load, compared to the TS421IDT's 367mW at 16Ohm load. This represents increased power delivery capability. Applications originally designed for the TS421IDT will operate within the LM4889's performance envelope without modification. The higher power rating does not introduce compatibility issues; it provides additional headroom for signal handling.

Q: Are there supply voltage compatibility concerns between the TS421IDT and LM4889 substitutes?

A: The TS421IDT operates from 2V to 5.5V. The LM4889MA/NOPB and LM4889MAX/NOPB operate from 2.2V to 5.5V. The 0.2V minimum voltage difference is negligible for most applications. Designs operating above 2.2V supply voltage experience full compatibility. Designs operating between 2V and 2.2V require verification that the LM4889 minimum specification does not violate application requirements.

Q: What is the difference between LM4889MA/NOPB and LM4889MAX/NOPB?

A: Both devices are Class AB mono amplifiers in 8-SOIC packages with identical electrical specifications and operating parameters. The primary difference is manufacturer designation: LM4889MA/NOPB is National Semiconductor; LM4889MAX/NOPB is Texas Instruments. Both are functionally equivalent for TS421IDT replacement. Selection should be based on availability and supply chain considerations.

Q: Is the TS421IDT obsolescence a concern for long-term production?

A: Yes. The TS421IDT is classified as obsolete, indicating STMicroelectronics has discontinued production. For new designs or ongoing production requiring this amplifier topology, the LM4889MAX/NOPB or LM4889MA/NOPB are active production alternatives. Both substitute parts are currently manufactured and available in volume quantities.

Q: Do the substitute parts maintain RoHS3 compliance?

A: The LM4889MAX/NOPB is explicitly ROHS3 compliant. The LM4889MA/NOPB RoHS status is not specified in available documentation. For applications requiring certified RoHS3 compliance, the LM4889MAX/NOPB is the appropriate selection.

Q: Are there feature differences between the TS421IDT and LM4889 substitutes?

A: The TS421IDT includes Differential Inputs, Short-Circuit Protection, and Standby features. The LM4889 series includes Depop, Shutdown, and Thermal Protection features. Both device families provide protection mechanisms appropriate for audio amplifier applications. Feature sets differ in implementation but serve equivalent protective functions for audio signal amplification.