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Home > Products > Integrated Circuits (ICs) > Audio Special Purpose

STMicroelectronics TDA7438D

Name: TDA7438D
Brand: STMicroelectronics
SKU: TDA7438D
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: TDA7438D

Manufacturer:: STMicroelectronics

Category:: Audio Special Purpose

Package:: 28-SOIC (0.295", 7.50mm Width)

Datasheet:: TDA7438D.pdf

Description:: IC AUDIO TONE PROCESSOR 28SO

Quantity:: RFQ Add To RFQ list

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Inventory:4,688

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Product details

Overview

TDA7438D from STMicroelectronics is a digitally controlled, three-band audio processor IC for car-radio and Hi-Fi systems. It integrates stereo input multiplexing (3 inputs), independent bass/middle/treble control in 2.0 dB steps, volume control in 1.0 dB steps, dual speaker attenuators with mute, and I²C serial bus programming. Its bipolar/CMOS process delivers low distortion (0.01% typ.), high signal-to-noise ratio (106 dB), and DC step-free operation.

For engineers reviewing the TDA7438D datasheet, TDA7438D pinout, TDA7438D application, or TDA7438D equivalent, this device serves as a complete analog audio signal conditioning solution where precise digital control of tone, balance, volume, and speaker output is required in automotive and consumer audio platforms.

Technical Context

The TDA7438D implements a fully analog signal path with digitally programmable resistor networks and operational amplifiers for tone and volume processing. All controls-including input gain selection (0–30 dB), treble/middle/bass (±14 dB), volume (−47 to 0 dB), and speaker attenuation (−79 dB) -are set via I²C interface using 8-bit subaddress registers.

Its architecture separates signal routing (input multiplexer), level adjustment (volume/speaker attenuators), and frequency-shaping (bass/middle/treble filter cells with external RC components). Each tone stage uses internal feedback resistors (e.g., 44 kΩ for bass, 25 kΩ for middle, 25 kΩ for treble) to define center frequency and Q-factor when paired with external capacitors.

Key Specifications

Parameter	Value and Actual Design Meaning
Supply Voltage	6–10.2 V - Supports standard 9 V automotive rail with ±10% tolerance margin.
THD + N	0.01% typ. at 1 Vrms - Enables high-fidelity audio without audible distortion in mid-power stages.
Signal-to-Noise Ratio	106 dB - Ensures clean output even at low volume settings, critical for quiet cabin environments.
Volume Control Range	−47 dB to 0 dB in 1 dB steps - Provides fine-grained loudness adjustment without audible stepping artifacts.
Bass/Treble/Middle Range	±14 dB in 2 dB steps - Allows precise tonal shaping across full audible spectrum for source-matched EQ.
Input Multiplexer	3 stereo inputs with selectable gain (0–30 dB) - Adapts signal levels from diverse sources (CD, tuner, aux) to common processing chain.
Speaker Attenuation	−79 dB range with independent left/right control and mute - Enables balanced multi-speaker systems and silent power-on sequencing.
I²C Interface	Standard-mode (100 kHz), 8-bit subaddressing - Compatible with legacy microcontrollers without requiring high-speed timing support.

Pinout & Package

Package: SO28 (Small Outline, 28-pin, 300 mil width, 1.27 mm pitch). RoHS-compliant surface-mount package optimized for compact automotive PCB layouts.

Pin/Terminal	Circuit Role	Design Meaning
1, 2, 3, 4, 5, 28	Stereo Input Terminals (L-IN1/R-IN1 to L-IN3/R-IN3)	Three independent stereo input pairs; each pair routed through programmable gain stage before multiplexing.
6, 8	Left/Right MUX Output (MUXOUTL/MUXOUTR)	Post-multiplexer analog outputs feeding volume and tone processing blocks; high-impedance buffered nodes.
7, 9	Left/Right Audio Outputs (LOUT/ROUT)	Main stereo outputs after full signal chain (volume, tone, balance); capable of driving 2 kΩ loads directly.
10, 11	Bass Input/Output (BIN(L)/BOUT(L))	External RC network connection points for bass filter; defines center frequency and boost/cut response shape.
12, 14	Middle Input/Output (MIN(L)/MOUT(L))	External RC network connection points for midrange filter; uses 25 kΩ internal feedback resistor.
13, 15	Treble Input/Output (TREBLE(L)/TREBLE(R))	High-pass filter nodes; internal 25 kΩ resistor sets time constant with external capacitor to ground.
17, 18	Speaker Attenuator Left/Right (SPKR ATT LEFT/RIGHT)	Dedicated analog attenuator outputs with independent 1 dB step control and mute function per channel.
19, 20	I²C Bus (SDA/SCL)	Open-drain bidirectional data and clock lines; require external pull-up resistors to VS.
21, 22	Analog/Digital Ground (AGND/DIG_GND)	Separate ground returns minimize noise coupling between analog signal path and digital control logic.
23, 24, 25, 26, 27	Reference & Power (CREF, VS, VREF, RB, RM)	CREF stabilizes internal reference voltage; VS supplies analog/digital sections; VREF provides bias; RB/RM set tone filter gain.

Key Features

Feature	Design Value
Three-band tone control	Independent bass/middle/treble adjustment (±14 dB, 2 dB steps) using external RC networks for customizable frequency response.
Input gain programmability	0–30 dB in 2 dB increments per input channel - eliminates manual gain staging and optimizes ADC/driver headroom.
Dual speaker attenuators	Left/right independent 1 dB step attenuation (−79 dB range) with hard mute - enables balanced multi-zone speaker management.
Low-distortion analog signal path	0.01% THD typ. and 106 dB SNR achieved via bipolar/CMOS hybrid process - preserves audio integrity without digital conversion artifacts.
I²C serial control interface	Standard-mode (100 kHz), 8-bit subaddress register map - simplifies integration with 8-bit microcontrollers and reduces PCB routing complexity.
No DC stepping during volume changes	Resistor-network-based attenuation avoids transient pops/clicks - essential for seamless user experience in automotive infotainment.

Applications

Automotive Head Unit

Aftermarket Car Stereo

Use Scenario: Integrated audio processor in OEM or Tier-1 head unit managing tuner, CD, Bluetooth, and USB inputs.

IC Role / Device Role / Timing Role: Central analog signal conditioner performing input selection, gain matching, tone shaping, volume leveling, and speaker-level attenuation.

Use Value: Eliminates need for discrete op-amp/EQ circuits and reduces BOM count by >12 components while maintaining <0.01% THD across temperature.

Use Scenario: Feature-rich aftermarket stereo supporting multiple input sources and customizable EQ presets.

IC Role / Device Role / Timing Role: Primary audio DSP front-end enabling real-time tone/volume/balance adjustments via rotary encoder or touchscreen UI.

Use Value: Enables 1 dB volume resolution and ±14 dB tone control without audible stepping, satisfying audiophile-grade expectations.

Hi-Fi Pre-Amplifier

Multi-Zone Audio Distribution

Use Scenario: High-fidelity preamp module in home theater receiver or integrated amplifier.

IC Role / Device Role / Timing Role: Analog signal router and equalizer between source components (DAC, phono, streamer) and power amp stage.

Use Value: Delivers 106 dB SNR and 90 dB channel separation - meets RIAA playback fidelity requirements without additional buffering.

Use Scenario: Central audio distribution hub routing one source to four independent speaker zones (e.g., kitchen, living room, patio, bedroom).

IC Role / Device Role / Timing Role: Speaker-level attenuator and balance controller providing independent volume control per zone via I²C commands.

Use Value: −79 dB speaker attenuation range allows precise level matching across zones with different speaker sensitivities and room acoustics.

Equivalent & Alternatives

The following parts are listed as comparable options for similar three-band audio processor applications.

Alternative Part	Technical Difference	Application Difference	Selection Advice
TDA7313	2-band tone control (bass/treble only), no middle band; 32-pin SOIC package; lower SNR (95 dB).	Lacks midrange adjustment - unsuitable for vocal-centric content or complex speaker compensation.	Select only if system design omits midrange tuning and requires cost reduction over full 3-band capability.
CS4272-CZZ	Audio codec with integrated 24-bit DAC/ADC; digital I²S interface; requires external analog filtering and amplification.	Replaces analog signal path with digital domain processing - increases MCU dependency and layout complexity.	Choose when digital audio sources dominate and system already includes DSP resources for FIR/EQ implementation.

Compared with TDA7438D, TDA7313 sacrifices midrange control and dynamic range for lower cost and pin count, while CS4272-CZZ shifts processing to digital domain-requiring additional analog circuitry and firmware development but enabling advanced parametric EQ and sample-rate flexibility.

Availability

TDA7438D is available at Aetrix Electronics and suitable for automotive infotainment systems, aftermarket car stereos, and Hi-Fi pre-amplifiers requiring stable component supply and long-term production continuity.

Supply support for TDA7438D 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, microcontroller, and sensor technologies for automotive, industrial, and consumer markets.

The TDA7438D belongs to ST's legacy audio processor product line, designed specifically for high-fidelity analog signal conditioning in resource-constrained embedded audio systems where low THD, high SNR, and I²C simplicity are prioritized over digital signal processing.

FAQ

What is the maximum input signal level the TDA7438D can handle without clipping?

The TDA7438D supports up to 2 V_RMS input signal level at the clipping threshold (THD = 0.3%). This is verified across all input channels and gain settings, ensuring compatibility with line-level outputs from CD players, tuners, and DACs without external attenuation.

Does the TDA7438D require external passive components for tone control?

Yes - bass, middle, and treble stages rely on external RC networks connected to dedicated IN/OUT pins (e.g., BIN(L)/BOUT(L), MIN(L)/MOUT(L), TREBLE(L)/TREBLE(R)). Component values determine center frequency and Q-factor; typical designs use 100 nF capacitors and 2.7–5.6 kΩ resistors.

Can the TDA7438D operate from a 5 V supply?

No - the absolute minimum supply voltage is 6 V, and the recommended operating range is 6–10.2 V. Operation below 6 V risks functional failure, including loss of I²C communication and degraded audio performance due to insufficient headroom in internal op-amps.

How does the TDA7438D handle power-on mute behavior?

At power-on reset, the TDA7438D defaults to muted output (−80 dB attenuation) and flat tone settings (0 dB bass/middle/treble, 0 dB volume). This prevents turn-on thumps and ensures predictable startup state until host MCU writes configuration via I²C bus.

TDA7438D Specifications

Product attributes: Attribute value

Manufacturer:: STMicroelectronics

Series:: -

Package/Case:: 28-SOIC (0.295", 7.50mm Width)

Packaging:: Tube

Product Status:: Obsolete

Function:: Audio Tone Processor

Applications:: Audio

Number of Channels:: 2

Interface:: I2C

Voltage - Supply:: 6V ~ 10.2V

Operating Temperature:: 0°C ~ 70°C (TA)

Specifications:: -

Mounting Type:: Surface Mount

Grade:: Automotive

TDA7438D FAQ

1.How can I place an order for TDA7438D through Aetrix?

Please submit a Request for Quotation (RFQ) for TDA7438D on Aetrix. Our sales agent will provide a competitive quotation and guide you through the order confirmation once you accept the terms.

2.Are the price and stock information for TDA7438D reliable?

The price and inventory of TDA7438D are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for TDA7438D is usually 5 days.

3.What payment methods are accepted for TDA7438D?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for TDA7438D transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for TDA7438D?

TDA7438D orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your TDA7438D order is processed, you will receive an email with the shipment details and tracking number.

Note: Tracking information may take up to 24 hours to appear. Express delivery typically takes 3–5 business days.

5.How can I obtain technical support or documentation for TDA7438D?

For technical support, including TDA7438D datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your TDA7438D requirements.

6.How does Aetrix verify that TDA7438D is sourced from the original manufacturer or authorized distributors?

All TDA7438D products on Aetrix are procured from qualified distributors and authorized channels. Our dedicated quality assurance team conducts strict verification, including traceability checks and, if necessary, third-party testing. This ensures that TDA7438D meets industry standards.

7.What is the process for return or replacement of TDA7438D?

All TDA7438D units undergo pre-shipment inspection (PSI). If there is an issue with TDA7438D, returns or replacements are accepted under the following conditions:

1.Quantity discrepancies, incorrect items, or visible external defects (such as breakage or corrosion), acknowledged by Aetrix.

2.The issue is reported within 90 days of delivery.

3.The TDA7438D part is unused and in its original packaging.

Return procedure for TDA7438D:

1.Submit a request within 90 days.

2.Obtain a Return Material Authorization (RMA) from Aetrix.

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