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

STMicroelectronics TDA7438

Name: TDA7438
Brand: STMicroelectronics
SKU: TDA7438
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: TDA7438

Manufacturer:: STMicroelectronics

Category:: Audio Special Purpose

Package:: 28-DIP (0.600", 15.24mm)

Datasheet:: TDA7438.pdf

Description:: IC AUDIO TONE PROCESSOR 28DIP

Quantity:: RFQ Add To RFQ list

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Inventory:3,348

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Product details

Overview

TDA7438 from STMicroelectronics is a digitally controlled, three-band audio processor IC for car-radio and Hi-Fi systems, featuring stereo input multiplexing (3 inputs), independent left/right speaker attenuation (0 to –79 dB in 1.0 dB steps), and tone control (bass/middle/treble ±14 dB in 2.0 dB steps), all programmable via I²C bus.

For engineers reviewing the TDA7438 datasheet, TDA7438 pinout, TDA7438 application, or TDA7438 equivalent, this device supports precise analog signal conditioning with low distortion (0.01% THD), high channel separation (90 dB), and DC-free volume stepping - critical for noise-sensitive automotive infotainment and premium audio front-ends.

Technical Context

The TDA7438 implements a bipolar/CMOS hybrid architecture to achieve low noise (5 µV output noise), low distortion, and zero DC stepping during volume/tone adjustments. Its analog signal path uses resistor networks and operational amplifiers, with external passive components defining filter center frequencies for bass, middle, and treble bands.

Control logic resides in an integrated I²C decoder with latches; all functions-including input gain selection (0–30 dB), mute (≥80 dB attenuation), and speaker balance-are configured via 8-bit subaddress registers. The chip supports both incremental and non-incremental I²C write modes for flexible firmware integration.

Key Specifications

Parameter	Value and Actual Design Meaning
Supply Voltage	6–10.2 V - Operates across automotive battery range with ripple rejection ≥60 dB
THD + N	0.01% typ. at 1 Vrms - Enables high-fidelity audio without audible artifacts
Signal-to-Noise Ratio	106 dB - Supports dynamic range required for CD-quality playback
Channel Separation	90 dB at 1 kHz - Ensures clean stereo imaging in compact PCB layouts
Volume Control Range	–47 dB to 0 dB in 1.0 dB steps - Provides fine-grained loudness adjustment without zipper noise
Bass/Middle/Treble Range	±14 dB in 2.0 dB steps - Allows precise tonal shaping per band with external RC tuning
Input Gain Adjustment	0–30 dB in 2 dB steps - Matches varying source levels (e.g., tuner vs. CD player)
Mute Attenuation	≥80 dB - Fully silences output without pop/click during transitions

Pinout & Package

Available in DIP28 (through-hole) and SO28 (surface-mount) packages. Both variants share identical pin mapping and thermal characteristics (R_{th j-pins} = 85 °C/W).

Pin/Terminal	Circuit Role	Design Meaning
1, 2, 3, 4, 5, 28	L/R Input Channels	Accepts three stereo inputs (L-IN1–L-IN3, R-IN1–R-IN3); internal multiplexer selects one pair
6, 8	Speaker Attenuator Outputs	BOUT(L)/BOUT(R): Bass-filtered outputs feeding external speaker drivers
7, 9	Middle Filter Inputs/Outputs	MOUT(L)/MOUT(R): Middle-band signal path with configurable Q and center frequency
10, 11	Treble Filter Inputs/Outputs	TREBLE(L)/TREBLE(R): High-pass stage with fixed internal 25 kΩ resistor
12, 14	Audio Outputs	LOUT/ROUT: Final stereo outputs with 2.1 Vrms clipping level into 2 kΩ load
13, 15	Input Multiplexer Outputs	MUXOUTL/MUXOUTR: Post-gain, pre-volume signals routed to tone processing blocks
17, 18	I²C Interface	SCL/SDA: Bidirectional serial bus lines with standard open-drain timing and ACK protocol
20, 21, 22, 23, 24, 25, 26, 27	Analog Ground & Reference	DIG_GND, AGND, CREF, VREF, VS - Separate digital/analog grounds prevent coupling; CREF stabilizes internal bias

Key Features

Feature	Design Value
Three-band tone control	Independent bass/middle/treble adjustment (±14 dB, 2 dB step) using externally tuned RC filters
Dual speaker attenuators	Left/right channels independently adjustable from 0 to –79 dB (1 dB step) with dedicated mute
Programmable input gain	0–30 dB in 2 dB increments enables optimal SNR matching across diverse audio sources
Zero-DC-step volume control	Eliminates audible "thumps" during real-time level changes in automotive environments
I²C-compatible interface	Supports both auto-increment and fixed-subaddress writes for streamlined MCU firmware integration
Low-noise analog core	5 µV output noise (20 Hz–20 kHz) ensures clean signal chain even after multiple gain stages

Applications

Car Audio Head Unit

Hi-Fi Preamp Module

Use Scenario: Central audio processor in OEM dashboard head units handling tuner, CD, and auxiliary inputs.

IC Role / Device Role / Timing Role: Input multiplexer, tone shaper, and speaker-level attenuator - manages analog signal routing before power amplification.

Use Value: 30 dB selectable input gain compensates for inconsistent source output levels; 90 dB channel separation preserves stereo imaging in cramped vehicle cabins.

Use Scenario: Standalone preamplifier stage in home stereo receivers supporting multiple line-level sources.

IC Role / Device Role / Timing Role: Analog signal conditioner providing user-adjustable EQ and balance prior to DAC or power amp stages.

Use Value: ±14 dB per-band tone control with external RC tuning allows audiophile-grade customization; 106 dB S/N ratio maintains transparency in high-resolution playback.

Aftermarket Car Stereo

Professional Monitor Controller

Use Scenario: Signal processing core in plug-and-play aftermarket radios replacing factory units.

IC Role / Device Role / Timing Role: Volume, balance, and tone controller interfacing between source decoders and Class AB amplifier modules.

Use Value: Independent left/right speaker attenuation (–79 dB range) enables precise cabin acoustic compensation; mute function suppresses turn-on transients.

Use Scenario: Front-end control unit for studio monitor switching and tonal calibration.

IC Role / Device Role / Timing Role: Precision analog gain and EQ engine managing reference-level monitoring paths with minimal coloration.

Use Value: 0.01% THD ensures neutral signal path; separate bass/middle/treble controls allow room correction without affecting overall level.

Equivalent & Alternatives

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

Alternative Part	Technical Difference	Application Difference	Selection Advice
TDA7313	2-band tone control (bass/treble only); no middle band; lower max. input gain (24 dB)	Lacks midrange adjustment needed for vocal clarity tuning in voice-centric systems	Select when cost sensitivity outweighs need for full 3-band EQ and higher input gain headroom
CS4272-CZZ	Integrated 24-bit stereo DAC + DSP; requires external microcontroller for tone algorithms; no analog input multiplexer	Replaces analog signal path with digital domain processing; demands firmware development	Choose for fully digital audio architectures where flexibility and future-proofing justify added complexity

Compared with TDA7313, the TDA7438 adds middle-band control and +6 dB input gain range - essential for accurate vocal reproduction and legacy analog source compatibility. Against CS4272-CZZ, it offers simpler analog integration and deterministic latency without DSP coding overhead.

Availability

TDA7438 is available at Aetrix Electronics and suitable for car-radio head units, Hi-Fi preamplifiers, and aftermarket audio processors requiring stable component supply across extended production lifecycles.

Supply support for TDA7438 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 automotive ICs with strong heritage in audio signal processing.

The TDA7438 belongs to ST's legacy automotive audio processor family, designed specifically for analog-domain tone/volume/balance control in cost-sensitive, high-reliability infotainment systems.

FAQ

What is the maximum input signal level the TDA7438 can handle without clipping?

The TDA7438 supports up to 2 Vrms input signal level (V_CL) at 0.3% THD, verified under typical conditions (T_amb = 25°C, V_S = 9 V). This headroom accommodates peak transients from CD players and digital sources while maintaining linearity across its full 30 dB input gain range.

Does the TDA7438 require external passive components for tone control?

Yes - bass, middle, and treble bands rely on external resistors and capacitors connected to dedicated IN/OUT pins (e.g., BIN(L)/BOUT(L), MOUT(L)/MOUT(R), TREBLE(L)/TREBLE(R)). Component values determine center frequency, Q factor, and boost/cut response shape per band, as defined by ST's design equations in the datasheet.

Can the TDA7438 operate from a 5 V supply?

No - the absolute minimum supply voltage is 6 V, and operation above 10.2 V risks damage. It is engineered for automotive 9–10.2 V nominal systems and will not function reliably at 5 V. For 5 V designs, consider newer alternatives like the STA559BW or digital audio processors with integrated LDOs.

Is there hardware reset functionality on the TDA7438?

No dedicated reset pin exists, but the device performs automatic power-on reset (POR) when V_S rises above threshold. Internal POR circuitry initializes all registers to default states (e.g., volume = 0 dB, tone = flat, mute = off), ensuring predictable startup behavior without external supervision.

TDA7438 Specifications

Product attributes: Attribute value

Manufacturer:: STMicroelectronics

Series:: -

Package/Case:: 28-DIP (0.600", 15.24mm)

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:: Through Hole

Grade:: Automotive

TDA7438 FAQ

1.How can I place an order for TDA7438 through Aetrix?

Please submit a Request for Quotation (RFQ) for TDA7438 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 TDA7438 reliable?

The price and inventory of TDA7438 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for TDA7438 is usually 5 days.

3.What payment methods are accepted for TDA7438?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for TDA7438 transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for TDA7438?

TDA7438 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your TDA7438 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 TDA7438?

For technical support, including TDA7438 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your TDA7438 requirements.

6.How does Aetrix verify that TDA7438 is sourced from the original manufacturer or authorized distributors?

All TDA7438 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 TDA7438 meets industry standards.

7.What is the process for return or replacement of TDA7438?

All TDA7438 units undergo pre-shipment inspection (PSI). If there is an issue with TDA7438, 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 TDA7438 part is unused and in its original packaging.

Return procedure for TDA7438:

1.Submit a request within 90 days.

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

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