STMicroelectronics STA559BWSTR

Overview

STA559BWSTR from STMicroelectronics is a 2.1-channel high-efficiency digital audio system-on-chip (Sound Terminal®) integrating FFX™ ternary/binary PWM amplification, configurable DSP, and I²C-controlled audio processing. It delivers up to 2 × 0.7 W + 1 × 3 W into 4 Ω at 5 V (binary 2.1 mode), supports 32–192 kHz sample rates, and embeds thermal/short-circuit protection in PowerSSO-36 EPD package - used in compact stereo soundbars and portable multimedia docks.

For engineers reviewing the STA559BWSTR datasheet, STA559BWSTR pinout, STA559BWSTR application, or STA559BWSTR equivalent, key selection considerations include output configuration flexibility (ternary stereo + PWM, ternary stereo + line-out, or binary 2.1), integrated limiter/compressor control, user-programmable biquad filters per channel, and AM interference suppression for EMI-sensitive consumer audio designs.

Technical Context

The STA559BWSTR implements a multi-mode FFX™ PWM architecture with selectable ternary or binary output stages, enabling simultaneous optimization of power efficiency and THD+N across varying load impedances (2 Ω to 8 Ω). Its digital audio path includes dual I²S inputs, programmable input mapping, and three independent coefficient banks for fast EQ preset recall via I²C.

Real-time signal conditioning is handled by two independent limiters with configurable attack/release thresholds and rates, plus dynamic range compression or anti-clipping modes. The device integrates automatic invalid-input detect mute, zero-crossing soft volume update, and selectable high-pass filtering for DC blocking - all controllable through 72+ registers mapped to I²C addresses 0x00–0x2C.

Key Specifications

Pinout & Package

STA559BWSTR is housed in PowerSSO-36 EPD (Exposed Pad Down), a thermally enhanced surface-mount package with 36 leads and an internal thermal pad soldered to PCB ground plane for efficient heat dissipation in high-power-density audio modules.

Key Features

Applications

Equivalent & Alternatives

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

Compared with TAS5756MRTVR and MAX98357AETE+, STA559BWSTR uniquely combines ternary/binary mode flexibility, embedded AM suppression, and full 2.1 DSP in one die - reducing total solution size and eliminating external signal routing complexity in compact consumer audio products.

Availability

STA559BWSTR is available at Aetrix Electronics and suitable for compact soundbars, USB-C docking stations, smart TV audio modules, and portable Bluetooth speakers requiring stable component supply and long-term production continuity.

Supply support for STA559BWSTR 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, Switzerland, designing and manufacturing microcontrollers, power management ICs, sensors, and analog/mixed-signal devices for industrial, automotive, and consumer markets.

STA559BWSTR belongs to ST's Sound Terminal® family - engineered specifically for space- and power-constrained consumer audio systems requiring integrated amplification, DSP, and robust EMI resilience without external processors.

FAQ

What output configurations does STA559BWSTR support, and how are they selected?

STA559BWSTR supports three configurations: (1) 2× ternary PWM + PWM output, (2) 2× ternary PWM + stereo line-out, and (3) binary 2.1 (left/right/LFE). Selection is made via the OCFG bits (register 0x02) over I²C - no hardware changes required. Each mode uses distinct PWM slot allocation and internal routing, validated in Figures 14–16 of the datasheet.

Does STA559BWSTR require external passive components for PWM output filtering?

Yes - each PWM output (OUTL, OUTR, OUTLFE) requires an external second-order LC filter (e.g., 10 µH inductor + 1 µF capacitor) to reconstruct analog audio and suppress switching noise. The datasheet specifies exact values and layout guidelines in Section 7.3 and Figure 19, with recommended ferrite-bead placement near the PowerSSO-36 EPD thermal pad.

How does the AM interference suppression feature operate in practice?

The device dynamically shifts its PWM carrier frequency away from the AM broadcast band (530–1710 kHz) using register-controlled AMGC[1:0] bits (0x0B), and applies selectable noise-shaping topologies (high/low bandwidth) via NSB[1:0] bits (0x1F). This eliminates audible heterodyne whines in proximity to AM radios - confirmed in application note AN4922.

Can STA559BWSTR be used without I²C control in basic playback mode?

No - I²C initialization is mandatory. The device powers up in reset state and remains non-operational until configuration registers (e.g., master clock select, output mode, volume) are written. Default values do not enable audio path; even mute bypass requires explicit register write (bit MVOL[7] = 1 in addr 0x07).