STMicroelectronics DEMOTS4909Q

Overview

TS4909 from STMicroelectronics is a dual-mode stereo headphone amplifier IC designed for portable audio systems, delivering 158 mW into 16 Ω at 5 V (1% THD+N), operating from 2.2–5.5 V supply, featuring capacitor-less phantom-ground and single-ended output topologies with 10 nA standby current.

For engineers reviewing the TS4909 datasheet, TS4909 pinout, TS4909 application, or TS4909 equivalent, this page provides verified functional context, validated pin roles, confirmed dual-output mode behavior, real-world power efficiency trade-offs between SE and PHG configurations, and application-specific SNR/crosstalk performance metrics.

Technical Context

The TS4909 integrates two independent Class-AB amplifier channels with selectable output architecture: phantom-ground (PG) mode eliminates DC-blocking capacitors via internal virtual ground generation, while single-ended (SE) mode disables PG to reduce quiescent current by ~30%. It uses external resistive feedback (R_in/R_feed) for gain setting and includes dedicated SE/PHG and active-low STDBY control inputs.

Pop-and-click suppression is implemented via internal soft-start circuitry synchronized to wake-up timing (50 ms in PG, 100 ms in SE mode); PSRR reaches 72 dB at 1 kHz in PG configuration with grounded inputs and 1 µF bypass capacitor, and crosstalk exceeds 110 dB at 1 kHz for SE outputs.

Key Specifications

Pinout & Package

TS4909 is housed in a lead-free DFN10 (3 mm × 3 mm, 0.5 mm pitch) package with exposed thermal pad for enhanced power dissipation in space-constrained portable PCBs.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX4410ETE+ and TAS5707PAP, the TS4909 uniquely balances capacitor-less operation, ultra-low standby, and dual-mode flexibility-making it optimal for analog-input portable devices where board space, battery life, and acoustic quality are co-constrained.

Availability

TS4909 is available at Aetrix Electronics and suitable for mobile handset audio, portable media players, tablet audio subsystems, and wireless headphone dongles requiring stable component supply across extended production lifecycles.

Supply support for TS4909 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 specializing in microcontrollers, analog ICs, and power management solutions for automotive, industrial, and consumer markets.

The TS4909 belongs to ST's low-power audio amplifier product line, engineered specifically for space- and energy-constrained portable audio endpoints requiring high-fidelity output without bulky passive components.

FAQ

What is the minimum supply voltage for reliable operation of the TS4909?

The TS4909 is specified to operate down to 2.2 V per its absolute maximum ratings table. At 2.6 V, it delivers 38 mW into 16 Ω (1% THD+N); performance degrades gradually below this, but functionality remains stable across the full −40°C to +85°C temperature range.

How does the SE/PHG pin affect output configuration and power consumption?

When SE/PHG is pulled high, the device operates in single-ended mode: Vout3 is disabled, standby current drops ~30%, and output swing is reduced by ~15% versus phantom-ground mode. When pulled low, Vout3 becomes an active virtual ground node, enabling capacitor-less coupling and maximizing output power and voltage swing.

Can the TS4909 drive 32 Ω headphones effectively at 3.0 V?

Yes: in phantom-ground mode at 3.0 V, it delivers 31 mW into 32 Ω with <1% THD+N at 1 kHz, meeting loudness requirements for most consumer headphones. SNR remains 101 dB (A-weighted), ensuring clean audio reproduction without audible hiss.

Is external gain-setting required, and what resistor values are recommended?

Yes - gain is set externally via R_in and R_feed per channel (AV = −R_feed/R_in). For unity gain, 20 kΩ R_in and 20 kΩ R_feed are used in the typical application schematic; values scale linearly for higher gains, with stability maintained up to AV = 4 per ST's characterization data.