The Original TDA7419 3 Band Car Audio Processor is a high-performance, I2C-bus controlled integrated signal processor manufactured by STMicroelectronics. Encapsulated in a compact SOP-28 (SO-28) surface-mount package, it is specifically designed for high-end car radios, premium automotive infotainment systems, and multi-channel audio equipment. Featuring a fully integrated 3-band tone control (Bass, Middle, Treble) with fully selectable center frequencies and quality factors, the TDA7419 incorporates soft-step volume, fader, and balance attenuation, along with advanced stereo input multiplexing (including quasi-differential and full differential inputs), dedicated subwoofer output filters, and spectrum analyzer support. It delivers ultra-low total harmonic distortion (THD = 0.002% typ.), low output noise (Vno = 8µV typ.), and pop-free audio switching via internal zero-crossing detectors and soft-mute logic.

Specifications

• Part Number / Model: TDA7419 / TDA7419TR
• Manufacturer: STMicroelectronics
• Device Type: 3-Band Audio Signal Processor with Integrated I2C Interface
• Package Type: SOP-28 
• Operating Supply Voltage (Vs): 7.5V to 10.5V DC (Typ. 8.5V)
• Supply Current (Is): Typ. 30mA / Max. 45mA (at Vs = 8.5V)
• Control Interface: Standard I2C Bus Protocol (Bidirectional 100kHz / 400kHz fast mode)
• Input Channels: 4 Stereo Single-Ended Inputs, 1 Quasi-Differential Input, 1 Full-Differential Input, 1 Mono / Phone Input
• Output Channels: 6 Output Channels (Front Left/Right, Rear Left/Right, Subwoofer / Center Channel)
• Volume Control Range: +15dB to -79dB in 1dB steps (with soft-step smooth attenuation)
• Tone Control Range:
  • Bass: ±15dB (100Hz, 80Hz, 60Hz, 200Hz selectable center frequencies) with variable Q-factor (1.0, 1.25, 1.5, 2.0) and DC-mode
  • Middle: ±15dB (500Hz, 1kHz, 1.5kHz, 2.5kHz selectable center frequencies) with variable Q-factor (0.75, 1.0, 1.25)
  • Treble: ±15dB (10kHz, 12.5kHz, 15kHz, 17.5kHz selectable center frequencies)
• Subwoofer Low-Pass Filter: 80Hz, 120Hz, 160Hz (2nd-order Butterworth filter)
• Total Harmonic Distortion (THD): Typ. 0.002% / Max. 0.08% (at f = 1kHz, Vin = 1Vrms, Vol = 0dB)
• Signal-to-Noise Ratio (SNR): Typ. 106dB (A-weighted, Vol = 0dB)
• Output Noise Voltage (Vno): Typ. 8µV / Max. 15µV (A-weighted, all stages flat)
• Channel Separation: Typ. 100dB (at f = 1kHz)
• Input Impedance: Typ. 50kΩ (Single-ended inputs)
• Maximum Output Voltage: Min. 2.0Vrms / Typ. 2.5Vrms (at THD = 0.3%, Vs = 8.5V)
• Operating Ambient Temperature (Tamb): -40°C to +85°C
• Storage Temperature Range (Tstg): -55°C to +150°C
• I2C Device Address: 0x88 (Write mode: 10001000b / Read mode: 10001001b)

Features

• Fully Integrated 3-Band Equalizer: Bass, Middle, and Treble filters with digitally programmable center frequencies, gain steps (±15dB in 1dB increments), and Q-factor settings with zero external components required.
• Pop-Free Soft-Step Switching: Integrated soft-step attenuation for Volume, Tone, and Mute adjustments ensures clean, click-less, and pop-free volume transitions during user adjustments.
• Versatile Input Architecture: Houses 4 single-ended stereo inputs, a full differential stereo input (for CD/Bluetooth/Aux noise rejection), and an auxiliary mono input for hands-free navigation and telephone interrupt routing.
• Dedicated Subwoofer Output: Includes a digitally controllable 2nd-order active low-pass filter (80Hz, 120Hz, 160Hz) with dedicated attenuation control for active bass channel drivers.
• Internal Spectrum Analyzer Filter: Features a built-in 7-band spectrum analyzer sub-circuit with multiplexed output, simplifying front-panel graphic audio visualizer integration.
• I2C-Bus Interface: Complete digital programmability over standard 2-wire I2C lines (SCL, SDA) with auto-increment address sequencing for high-speed register updates.

Common Applications

• Automotive Infotainment & Car Audio Units: OEM head units, aftermarket Android/CarPlay car stereos, and multi-channel audio DSP motherboards.
• Home Theater & Surround Pre-amplifiers: 5.1 / 6-channel audio preamplifier consoles, active multi-zone home sound hubs, and soundbars.
• Professional Audio Mixing Consoles: Multi-source audio selection, EQ filtering, and master gain/fader distribution blocks.
• Marine & RV Audio Systems: Noise-immune differential audio routing and multi-channel distribution in high-vibration mobile environments.
• Smart Speaker & Hi-Fi Audio Systems: Master volume, tone shaping, and crossover control prior to Class-D power amplifier stages.

Usage Tips

• Clean Supply Decoupling: Power the chip with a clean, regulated 8.5V DC rail. Place a 10µF low-ESR tantalum/electrolytic capacitor in parallel with a 100nF ceramic capacitor as close as possible to the Vs (Pin 28) and GND pins to prevent digital switching noise from bleeding into the audio floor.
• Input Coupling Capacitors: All analog audio inputs (single-ended and differential) require series DC-blocking film or low-leakage electrolytic capacitors (typically 2.2µF to 4.7µF) to avoid shifting internal DC bias points.
• I2C Bus Pull-Up Resistors: Connect 4.7kΩ pull-up resistors on both the SDA and SCL lines to the microcontroller logic level supply (3.3V or 5V); ensure proper ground reference between the host MCU and the TDA7419.
• Zero-Crossing Soft Mute Routine: Utilize the built-in soft-step mute register sequence before switching audio source inputs to ensure 100% pop-free transitions during active audio playback.
• Layout & Shielding: Route analog audio input and output traces on the PCB away from high-speed digital lines (SCL, SDA) and keep them surrounded by solid ground planes to maintain the 106dB SNR rating.

Datasheet