STMicroelectronics STA339BWTR

Overview

STA339BWTR from STMicroelectronics is a 2.1-channel high-efficiency digital audio system IC integrating FFX® Class-D amplification, 24-bit DSP processing, and I²C-controlled audio enhancement. It delivers 2 × 9 W + 1 × 20 W into 2 × 4 Ω / 1 × 8 Ω at 18 V (2.1 mode), supports 32–192 kHz sample rates, features dual-band DRC, 15 preset crossovers, and operates from 5–26 V supply. It targets compact home theater soundbars and active subwoofer systems requiring integrated digital audio processing and power output.

For engineers reviewing the STA339BWTR datasheet, STA339BWTR pinout, STA339BWTR application, or STA339BWTR equivalent, key selection considerations include its ternary PWM output architecture, LFE-dedicated processing path, thermal/short-circuit protection, and PowerSSO-36 slug-down package for high-power thermal dissipation in space-constrained audio PCBs.

Technical Context

The STA339BWTR implements a fully digital audio signal chain: dual-channel I²S input feeds a 96 kHz internal processing engine with 24–28-bit precision, configurable biquad EQ (up to 8 per channel), and two independent DRC blocks usable as B2DRC or separate limiters. Its FFX® modulation supports three output configurations-stereo binary, 2.1 ternary, or stereo ternary + line-out-each with programmable gain, mute, and soft-volume update.

Control is handled via I²C with selectable slave address; register mapping enables fine-grained configuration of PWM speed, noise-shaping topology, AM interference suppression, max power correction, and dedicated LFE bass boost (0.5 dB/step). Thermal warning recovery, zero-detect mute, and invalid-input detection are embedded hardware functions-not software-dependent.

Key Specifications

Pinout & Package

STA339BWTR uses the PowerSSO-36 (slug-down) package: a thermally enhanced 36-pin exposed-pad surface-mount housing with integrated heatsink contact on the underside. The slug-down configuration requires soldering the exposed thermal pad directly to a large copper pour for optimal thermal resistance (R_thJA = 3.5 °C/W typical).

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar 2.1-channel digital audio system applications.

Compared with TAS5756M and MAX98927, STA339BWTR uniquely integrates LFE-specific signal routing, ternary PWM for higher efficiency at low frequencies, and 15 factory-presets for crossover tuning-making it the only single-package solution for cost-sensitive, space-constrained 2.1 audio systems requiring no external DSP or amplifier stages.

Availability

STA339BWTR is available at Aetrix Electronics and suitable for soundbar manufacturing, active subwoofer production, and entry-tier home theater receiver design requiring stable component supply, long-term lifecycle assurance, and traceable sourcing.

Supply support for STA339BWTR 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, and microcontroller technologies for industrial, automotive, and consumer markets.

The STA339BWTR belongs to ST's FFX® digital audio system-on-chip product line, designed specifically for high-efficiency, low-BOM-count audio subsystems in space- and cost-constrained consumer electronics.

FAQ

What are the supported I²S data formats and clocking requirements?

The STA339BWTR supports I²S, left-justified, and DSP serial audio interface formats. It accepts MCLK at 256×, 384×, or 512× the LRCK rate, enabling compatibility with 32–192 kHz sample rates. LRCK polarity and data alignment are programmable via Configuration Register B (addr 0x01), and delay-clock-enable allows synchronization with source devices exhibiting variable setup times.

How does the dual-band DRC (B2DRC) function differ from standard limiter operation?

B2DRC splits the audio spectrum into low and high bands using configurable crossover points, then applies independent attack/release thresholds and gain reduction to each band. This prevents high-frequency masking during bass-heavy passages-unlike single-band limiters that compress the entire signal. Configuration is done via registers 0x12–0x15 and extended DRC mode (addr 0x36 bit 0).

Can the STA339BWTR drive 4 Ω loads in stereo mode, and what derating applies?

Yes-the device supports 4 Ω loads in stereo binary mode (OCFG=00), delivering 2 × 15 W at 18 V. However, thermal derating is required: above 65 °C ambient, output power must be reduced linearly per the PowerSSO-36 derating curve (Fig. 26), reaching 0 W at 115 °C. Adequate copper pour and airflow are mandatory for sustained 4 Ω operation.

Is the PowerSSO-36 slug-down package compatible with standard reflow profiles?

Yes-PowerSSO-36 (slug-down) is qualified for lead-free reflow per JEDEC J-STD-020. Peak temperature must not exceed 260 °C for ≤10 seconds. Critical process requirements include full solder coverage under the thermal slug (≥90% voiding allowed), minimum 0.2 mm stencil aperture for the exposed pad, and use of Type 3 or finer solder paste to prevent bridging on fine-pitch pins.