STMicroelectronics STA311B

Overview

STA311B from STMicroelectronics is an 8-channel digital audio processor featuring FFX™ PWM output, 192 kHz internal processing at 24–36-bit precision, >100 dB SNR, and integrated 10 biquad EQ filters per channel. It supports DSD/SACD (6 channels), selectable 32–192 kHz input sampling, and dual independent limiters for dynamic range control in home theater and AV receiver systems.

For engineers reviewing the STA311B datasheet, STA311B pinout, STA311B application, or STA311B equivalent, this page delivers verified functional identity, validated VFQFN-56 pin mapping, confirmed FFX™ damped ternary/binary PWM operation, real-world AutoMode presets (e.g., movie nighttime listening, TV AGC), and precise register-level DSP configuration capabilities - all critical for multichannel audio system integration and pop-free amplifier interface design.

Technical Context

The STA311B implements a fully programmable 8-channel audio signal chain with pre- and post-EQ 8-channel mixing, individual channel trim (±10 dB), and soft/hard mute with zero-detect and clock-loss power-down. Its dual limiter/compressor blocks operate in anti-clipping or dynamic range compression modes with user-configurable attack/release thresholds and rates via dedicated registers (0x2D–0x32).

FFX™ output stage supports per-channel selectable damped ternary or binary PWM, variable output delay control (registers 0x33–0x36), and max power correction to reduce full-power THD. I²S recombination enables flexible channel mapping (input→processing→FFX→output), while AM interference suppression uses automatic PWM frequency shifting and noise suppression modes.

Key Specifications

Pinout & Package

STA311B is housed in a VFQFN-56 (8 × 8 mm) package with 56 terminals, including 8 dedicated FFX™ PWM output pairs (OUT1A/B through OUT8A/B), dual I²S interfaces (SAI and I²S recombination), I²C control bus, and analog ground/power pins. The exposed thermal pad (EPAD) is electrically connected to VSS and must be soldered for thermal integrity.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar multichannel digital audio processor applications.

Compared with TAS5558 and AK4128AEV, the STA311B uniquely integrates native DSD64/128 support, hardware-accelerated AutoMode presets, and FFX™ PWM with pop-free sequencing - reducing firmware complexity and enabling true plug-and-play multichannel Class-D audio subsystems.

Availability

STA311B is available at Aetrix Electronics and suitable for home theater receivers, premium soundbars, studio monitor controllers, and SACD players requiring stable component supply, long-lifecycle support, and consistent FFX™ PWM performance across production batches.

Supply support for STA311B 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 analog, mixed-signal, and power ICs for automotive, industrial, and consumer applications.

The STA311B belongs to ST's FFX™ digital audio processor product line, designed specifically for high-fidelity, multichannel Class-D amplifier systems requiring integrated DSP, pop-free PWM control, and native DSD support without external converters.

FAQ

What is the maximum supported input sampling rate for the STA311B?

The STA311B supports input sampling rates from 32 kHz up to 192 kHz, as specified in Table 10 of the datasheet. This includes standard CD (44.1 kHz), DVD-Audio (96 kHz), and high-resolution streaming formats. The internal processing runs continuously at 192 kHz, ensuring consistent latency and filter response regardless of input rate.

Does the STA311B require an external microcontroller to use AutoMode features?

No. All AutoMode functions - including 32 preset EQ curves, movie nighttime mode, TV commercial AGC, and 5.1-to-2.0 downmix - are implemented in hardware and activated via single-register writes (e.g., AUTO1 at 0x1F). No external MCU or firmware is needed to enable or switch between these modes.

How does the STA311B achieve "pop-free" operation during power-up?

Pop-free operation is achieved through synchronized hardware sequencing: the device ramps PWM duty cycles from zero while holding outputs in high-impedance state, then transitions to active drive only after internal clocks stabilize and zero-detect confirms valid input. This sequence is fixed in silicon and requires no software initialization.

Can the STA311B drive Class-D amplifiers directly without external gate drivers?

No. The STA311B outputs FFX™ PWM signals (OUT1A/B through OUT8A/B), not high-current gate drive signals. These PWM outputs must interface with external Class-D half-bridge or full-bridge drivers (e.g., ST's STD10NF20L or similar) capable of translating logic-level PWM into MOSFET gate control.