STMicroelectronics STA304A

Overview

STA304A from STMicroelectronics is a single-chip digital audio processor implementing an end-to-end digital audio solution with integrated DSP, sample rate conversion, and 4+1-channel DDX™ Class-D PWM output drivers. It supports AC'97 Rev. 2.1 (6-channel), I²S (4-channel), and S/PDIF (stereo) inputs; features 100 dB SNR SRC; embedded 49.152 MHz PLL; and delivers direct digital amplification for driving external power bridges like STA500 in home theater and AV receiver systems.

For engineers reviewing the STA304A datasheet, STA304A pinout, STA304A application, or STA304A equivalent, key selection considerations include its 4+1 DDX™ PWM output architecture, automatic input sampling frequency detection (32–96 kHz), programmable I²S interfaces (input/output), AC'97/I²S/SPDIF source selection via AC97_MODE pin, and I²C-based full register control of parametric EQ, bass management, and soft mute functions.

Technical Context

The STA304A integrates a 20×20-bit fixed-point DSP core operating at 49.152 MHz (1024×48 kHz), with dedicated hardware blocks for dynamic/static equalization, bass/treble, phantom center, and bass redirection to LFE. Its sample rate converter (SRC) uses adaptive FIR interpolation or direct anti-aliasing filtering based on input frequency relative to configurable thresholds, achieving 100 dB SNR at 1 kHz.

Input routing is managed by three mutually exclusive interfaces - AC'97 (6-channel, 44.1/48/88.2/96 kHz), I²S (4-channel, 32–96 kHz slave or 48 kHz master), and S/PDIF (stereo, 32–96 kHz) - selected via AC97_MODE pin and internal registers. Output includes five PWM channels (Left_A/B, Right_A/B, LFE_A/B) plus six-channel programmable I²S for external DACs, all synchronized to a common 48 kHz internal domain.

Key Specifications

Pinout & Package

TQFP44 package with 44-pin quad flat no-lead footprint; 10 mm × 10 mm body, 0.8 mm pitch; lead-free and RoHS compliant.

Key Features

Applications

Equivalent & Alternatives

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

Compared with STA330, the STA304A offers proven TQFP44 integration and lower system cost for fixed 5.1 DDX™ applications, while CS497044-CQZ trades off integration for greater computational headroom in algorithm-intensive designs.

Availability

STA304A is available at Aetrix Electronics and suitable for home theater receivers, AV amplifiers, automotive infotainment head units, and smart soundbars requiring stable component supply and long-lifecycle support.

Supply support for STA304A 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, specializing in analog, MCU, power, and audio ICs for industrial, automotive, and consumer markets.

The STA304A belongs to ST's Digital Audio Processor product line, designed specifically to deliver fully integrated, low-component-count digital audio solutions for 5.1-channel consumer audio equipment with minimal external circuitry.

FAQ

Can the STA304A operate without an external crystal?

Yes - the STA304A supports both external crystal (6.144 MHz on XTI/XTO) and external clock input (24.576 MHz or 49.152 MHz). When using the 49.152 MHz clock, the PLL must be bypassed via PLL_Bypass bit; otherwise, the internal PLL generates the required 49.152 MHz from 6.144 MHz or 24.576 MHz references.

What is the function of the EAPD pin?

EAPD (External Amplifier Powerdown) is an active-low CMOS output that controls external Class-D power stages. It asserts low during device powerdown (PWDN) or mute events, enabling synchronized shutdown of downstream amplifiers to prevent pop/click artifacts and reduce standby power consumption.

Does the STA304A support DTS or Dolby Digital decoding?

No - the STA304A does not perform bitstream decoding of DTS or Dolby Digital. It processes PCM audio only. Decoded PCM from external decoders (e.g., via S/PDIF or I²S) can be fed into its inputs, where it applies EQ, bass management, and DDX™ modulation.

How is AC'97 Full-Compliant mode enabled?

AC'97 Full-Compliant mode is enabled by setting bit 0 (AC97_FC_mode) in CRA register (address 5Ah). In this mode, reserved bits in AC'97 register reads are masked to zero per Rev. 2.1 specification; in proprietary mode, full 16-bit RAM contents are returned without masking.