STMicroelectronics STA333ML13TR

Overview

STA333ML13TR from STMicroelectronics is a 2-channel microless digital audio system-on-chip integrating 24-bit DDX® Class-D amplification and embedded digital signal processing. It delivers 2 × 20 W into 8 Ω at 18 V, features 100-dB SNR, 96 kHz internal processing, and operates without external microcontroller control. Used in compact audio terminals like wireless speaker cradles and LCD audio systems.

For engineers reviewing the STA333ML13TR datasheet, STA333ML13TR pinout, STA333ML13TR application, or STA333ML13TR equivalent, key selection criteria include its filterless BTL capability, I²S interface compatibility, thermal/short-circuit protection architecture, and gain/oversampling configuration via hardware pins.

Technical Context

The STA333ML13TR implements a ternary 24-bit DDX® modulator with 384 kHz PWM carrier frequency and 96 kHz internal sample rate, enabling high-fidelity audio reconstruction without external DSP. Its dual half-bridge power stage uses matched P/N-channel DMOS with R_ds(on) ≤ 250 mΩ and integrated dead-time control (5–20 ns).

Protection logic includes autonomous thermal shutdown (140–150 °C), short-circuit current limiting (2.7–5.0 A), undervoltage lockout (3.5–4.3 V), and fault signaling via open-drain INT_LINE. Configuration is pin-driven: ONSEL selects 256×f_s or 384×f_s PLL clock ratio; GAIN sets output level to 0 dBFs or 24 dBFs.

Key Specifications

Pinout & Package

STA333ML13TR uses PowerSSO-36 EPD (exposed pad down) package: 36-pin thermally enhanced surface-mount housing with integrated ground plane connection via exposed copper pad (EP). Designed for high-power dissipation in compact PCB layouts.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar 2-channel digital Class-D amplifier applications.

Compared with TAS5756M and MAX98357A, STA333ML13TR uniquely balances microless operation, 2×20 W output, and full protection set - making it optimal for mid-power stereo audio endpoints where BOM reduction and reliability are primary design goals.

Availability

STA333ML13TR is available at Aetrix Electronics and suitable for LCD audio systems, wireless speaker cradles, and digital speaker modules requiring stable component supply, long-lifecycle availability, and production-ready qualification.

Supply support for STA333ML13TR 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 STA333ML belongs to ST's Sound Terminal® family - engineered to deliver full digital audio streaming with integrated processing and Class-D amplification for cost-effective, low-power audio endpoints.

FAQ

What is the minimum recommended PCB layout practice for thermal management?

Use a double-layer PCB with two 3 × 3 cm² copper ground areas connected to the exposed pad (EP) via ≥16 thermal vias. This achieves 24 °C/W junction-to-ambient thermal resistance in natural convection, enabling full 2×20 W output without forced cooling. Avoid isolating the EP pad or using insufficient via count, which raises junction temperature beyond 150 °C.

Can STA333ML13TR operate in filterless mode with 4 Ω speakers?

No - the datasheet specifies filterless operation only for 8 Ω loads. Driving 4 Ω speakers in filterless mode increases EMI and risk of instability due to higher current slew rates and parasitic resonance. For 4 Ω, use the recommended LC filter configuration per Figure 11 to maintain EMC compliance and output stability.

How does the automatic invalid input detect mute function work?

The IC monitors I²S data validity continuously. If LRCKI or BICKI signals stop toggling, or if SDI contains invalid framing (e.g., missing word clocks or corrupted bit alignment), the device mutes both channels within 100 ms and asserts INT_LINE low. Recovery occurs automatically once valid I²S synchronization resumes.

Is the 24-bit DDX® modulator compatible with 16-bit I²S input sources?

Yes - the DDX® engine accepts 16-, 20-, or 24-bit I²S data. Internally, it up-samples all inputs to 96 kHz/24-bit resolution before modulation. No external bit-depth conversion is needed; the device preserves LSB significance and applies dithering to prevent truncation artifacts in 16-bit streams.