STMicroelectronics TS4621MLEIJT

Overview

TS4621MLEIJT from STMicroelectronics is a Class-G stereo headphone amplifier with integrated step-down DC/DC converter, designed for battery-powered portable audio devices. It delivers 100 µW/channel at 2.1 mA total supply current (10 dB crest factor), achieves 0.006% typical THD+N at 1 kHz, 100 dB PSRR at 217 Hz, and operates from 2.3 V to 4.8 V supply. Its flip-chip package enables space-constrained smartphone and MP3 player designs.

For engineers reviewing the TS4621MLEIJT datasheet, TS4621MLEIJT pinout, TS4621MLEIJT application, or TS4621MLEIJT equivalent, key selection criteria include quiescent current (0.6 mA/channel), gain options (0 dB / 6 dB), capacitor-less output architecture, common-mode sense functionality, and thermal shutdown behavior in high-density portable layouts.

Technical Context

The TS4621MLEIJT implements a two-rail Class-G architecture where an internal buck converter dynamically supplies HPVDD (1.9 V) or PVSS (−1.2 V) to the amplifier core based on signal amplitude, reducing power dissipation versus fixed-rail Class-AB. The dedicated CMS pin enables precise ground-noise rejection by sensing common-mode voltage at the headphone jack.

It uses differential input topology with 24–33.2 kΩ input impedance and supports single-ended inputs via external biasing. Stability is ensured across capacitive loads (0.8–100 nF) using a mandatory 12 Ω series output resistor and internal compensation-no external coupling capacitors required at the outputs.

Key Specifications

Pinout & Package

TS4621MLEIJT uses a 16-bump flip-chip package (1.65 mm × 1.65 mm, 400 µm pitch) with solder bumps located underneath the die-no wire bonds or leads. Thermal resistance is 90 °C/W (junction-to-ambient), optimized for thin mobile PCBs.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar stereo headphone amplifier applications.

Compared with MAX97220AETE+T and TAS5707PAG, TS4621MLEIJT uniquely combines Class-G analog efficiency, integrated rail generation, capacitorless outputs, and CMS-based ground-noise rejection-making it optimal for analog-input, battery-limited, space-constrained portable audio where standby current and PCB area are critical.

Availability

TS4621MLEIJT is available at Aetrix Electronics and suitable for smartphone audio subsystems, portable media players, mobile internet devices, and portable CD/DVD players requiring stable component supply across multi-year production cycles.

Supply support for TS4621MLEIJT includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.

Manufacturer

STMicroelectronics is a global semiconductor leader headquartered in Geneva, specializing in analog, power, microcontrollers, and sensors for automotive, industrial, and consumer markets.

The TS4621MLEIJT belongs to ST's high-efficiency audio amplifier product line, engineered specifically for ultra-low-power, space-constrained portable audio applications where battery life, thermal density, and PCB real estate are primary design constraints.

FAQ

What is the minimum output series resistor value required for stable operation?

The TS4621MLEIJT mandates a minimum 12 Ω resistor in series with each output (VOUTL/VOUTR). This resistor ensures unconditional stability across capacitive loads from 0.8 nF to 100 nF and prevents oscillation due to cable capacitance or headphone impedance variations. Omitting or reducing this resistor risks instability and audible artifacts.

How does the CMS pin improve audio quality in portable designs?

The CMS (Common-Mode Sense) pin connects directly to the headphone jack ground point, enabling the amplifier to reject ground-bounce noise induced by digital switching or RF transceivers. This reduces low-frequency hum and pop/click artifacts by >20 dB compared to conventional ground-referenced outputs, especially critical in mixed-signal PCBs with split ground planes.

Can the TS4621MLEIJT operate with single-ended input signals?

Yes-single-ended inputs are supported using external biasing networks as shown in Figures 68–69 of the datasheet. The differential input stage must be configured with matched resistors to set common-mode voltage at AVDD/2. Layout must follow Section 4.4.1 recommendations, including dedicated AGND routing and avoidance of shared return paths with digital circuits.

What is the role of the internal step-down converter beyond power savings?

Beyond reducing quiescent current, the internal buck converter enables true Class-G rail switching: it supplies HPVDD (1.9 V) for low-amplitude signals and dynamically boosts to higher voltage during peaks. This preserves headroom while minimizing heat generation-critical for thermally isolated smartphone speaker/headphone modules where junction temperature must stay below 150 °C.