STMicroelectronics TDA7490

Overview

TDA7490 from STMicroelectronics is a dual-channel Class D audio power amplifier in Flexiwatt 25 package, delivering 25W + 25W into 8Ω (THD = 10%) and supporting bridge-tied load (BTL) mode for 50W mono output. It features split ±10V to ±25V supply operation, integrated STBY/MUTE control, thermal and short-circuit protection, and external clock synchronization - deployed in TV audio stages and home stereo amplifiers.

For engineers reviewing the TDA7490 datasheet, TDA7490 pinout, TDA7490 application, or TDA7490 equivalent, key selection criteria include its ±25V max supply, 200kHz switching frequency, 30dB closed-loop gain, 55dB mute attenuation, and BTL-capable dual PWM output architecture with bootstrap-driven half-bridges.

Technical Context

The TDA7490 integrates two independent Class D amplifier channels with internal PWM modulators, triangular waveform generators (T1/T2), and dual feedback loops (FEED1–FEED4) for stability. Each channel uses a bootstrap-driven half-bridge topology with dedicated positive/negative power rails (±VCCpow1/2) and regulated internal supplies (+5V, –5V, Vreg).

It supports both stereo and BTL configurations via external LC filter reconfiguration; oscillator frequency (100–230kHz) is set by external capacitor on OSC pin or synchronized externally. Protection logic triggers thermal shutdown at 150°C and disables outputs during overvoltage (>55V differential) or short-circuit events.

Key Specifications

Pinout & Package

Package: Flexiwatt 25 (vertical, 25-pin, heat sink tab on underside). Thermal resistance junction-to-case is 1°C/W, enabling direct mounting to heatsink via metal tab.

Key Features

Applications

Equivalent & Alternatives

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

Compared with TAS5142AIDR and TPA3116D2PWPR, the TDA7490 uniquely supports ±25V operation, external clock sync, and true BTL mono mode in one Flexiwatt 25 package - making it optimal for legacy split-rail TV platforms and designs requiring precise EMI timing control.

Availability

TDA7490 is available at Aetrix Electronics and suitable for flat-panel TV audio stages, home stereo final amplifiers, soundbar main drivers, and set-top box speaker outputs requiring stable component supply despite its obsolete status.

Supply support for TDA7490 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, power, microcontrollers, and automotive ICs.

The TDA7490 belongs to ST's legacy audio power amplifier product line, engineered specifically for high-efficiency, low-heat-consumption stereo amplification in consumer video equipment with strict mechanical constraints.

FAQ

What is the maximum safe supply voltage for continuous operation?

The TDA7490 supports ±25V DC supply under normal operation, with absolute maximum rating of ±30V. Sustained operation above ±25V risks exceeding thermal limits even at moderate output power. The overvoltage threshold is 55–60V differential (V_RMAX), triggering automatic standby mode to prevent damage.

Can the TDA7490 be used in single-ended (non-BTL) mode with 4Ω loads?

Yes - the TDA7490 delivers 25W per channel into 4Ω at ±16V supply and 10% THD. External LC filter components must be adjusted: inductance reduced to ~15µH and capacitance increased to 470nF per channel to maintain cutoff near 30kHz and avoid instability.

How does the STBY-MUTE pin function with mixed logic levels?

The STBY-MUTE pin combines two functions: 0–7V forces full standby (3–5mA quiescent current), 1.7–2.5V activates mute (60dB attenuation, outputs disabled), and 4–5V enables normal playback. Intermediate voltages (e.g., 2.6–3.9V) are undefined and may cause erratic behavior - use clean CMOS or open-collector drive.

Is an external heat sink mandatory for 25W/channel operation?

Yes - at 25W × 2 output into 8Ω with ±21V supply, dissipation reaches ~6W. With R_th(j-case) = 1°C/W and ambient ≤40°C, case temperature exceeds 100°C without heatsinking. A minimum 5°C/W aluminum heatsink (≥100cm² surface area) is required for continuous operation at rated power.