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

STMicroelectronics TDA7318D

Name: TDA7318D
Brand: STMicroelectronics
SKU: TDA7318D
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: TDA7318D

Manufacturer:: STMicroelectronics

Category:: Audio Special Purpose

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

Datasheet:: TDA7318D.pdf

Description:: IC AUDIO TONE PROCESSOR 28SO

Quantity:: RFQ Add To RFQ list

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Inventory:3,383

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Product details

Overview

TDA7318D from STMicroelectronics is a digital-controlled stereo audio processor IC for automotive and Hi-Fi systems, implementing volume, bass/treble tone, left/right balance, front/rear fader, 4-channel speaker attenuation, and 4-stereo-input selection with programmable gain (0–18.75 dB in 6.25 dB steps). It interfaces via I²C bus and uses bipolar/CMOS technology to achieve 0.01% THD, 106 dB SNR, and 100 dB mute attenuation.

For engineers reviewing the TDA7318D datasheet, TDA7318D pinout, TDA7318D application, or TDA7318D equivalent, key selection considerations include its 1.25 dB volume/fader/balance resolution, ±14 dB treble/bass control range, 4 independent speaker attenuators, I²C address 0x40, and SO28 package compatibility with legacy DIP28 layouts.

Technical Context

The TDA7318D integrates analog signal path switching, resistor-network-based gain/attenuation, and op-amp-based tone filtering-all digitally controlled via an I²C interface operating at ≤100 kbit/s. Its architecture separates input multiplexing (4 stereo sources), pre-processing (gain selection), and output conditioning (speaker-level attenuation, mute, tone shaping).

It implements four independent 1.25 dB-step speaker attenuators (LF/RF/LR/RR), dual 2 dB-step tone controls (bass/treble) with external RC tuning, and a dedicated I²C decoder/latch block that latches register writes without requiring continuous clocking-enabling stable operation in noisy automotive environments.

Key Specifications

Parameter	Value and Actual Design Meaning
Supply Voltage	6–10 V - supports standard 9 V automotive rail with 10.2 V absolute max rating.
Volume Control	−78.75 to 0 dB in 1.25 dB steps - enables precise loudness matching across source types.
Bass/Treble Range	±14 dB in 2 dB steps - allows wide tonal correction without clipping at 2 Vrms input.
Input Gain	0 to +18.75 dB in 6.25 dB steps - adapts to line-level (2 Vrms) and low-output (e.g., phono) sources.
Mute Attenuation	100 dB - fully silences outputs while preserving DC bias stability for downstream amplifiers.
THD+N	0.01% typ. at 1 Vrms - ensures high-fidelity signal integrity in mid-to-high-end audio chains.
SNR	106 dB - minimizes audible noise floor in quiet listening conditions.

Pinout & Package

Package: SO28 (Small Outline, 28-pin, 300 mil width, 1.27 mm pitch); pin-compatible with obsolete DIP28 variant but surface-mount optimized.

Pin/Terminal	Circuit Role	Design Meaning
1, 2, 3, 4	L1–L4 Left Input	Four differential-capacitor-coupled left-channel inputs; selected via I²C audio switch register.
5, 6, 7, 8	R1–R4 Right Input	Corresponding right-channel inputs; each pair shares selectable gain setting.
16, 17	OUT(L), OUT(R)	Main stereo outputs - buffered, 75 Ω typical output impedance, 2.5 Vrms clipping level.
18–21, 23–26	SPKR ATT LF/RF/LR/RR	Four dedicated speaker-level attenuator outputs - each independently controllable in 1.25 dB steps.
27, 28	SCL, SDA	I²C serial interface - 100 kbit/s max, open-drain with internal pull-downs, compatible with 3.3 V/5 V µP buses.
9–11, 13–15, 19, 22	AGND, DIGGND, CREF, VCC	Analog/digital ground separation, reference capacitor node (2.2 µF), and 9 V supply input - critical for noise isolation.

Key Features

Feature	Design Value
4-Channel Speaker Attenuation	Independent 1.25 dB-step control per speaker (LF/RF/LR/RR) enables true 4-zone audio distribution without external DACs or switches.
I²C Address 0x40	Fixed 7-bit slave address (10001000) simplifies multi-device bus design and avoids address conflict in head-unit systems.
External Tone Filter Tuning	Bass/treble center frequency and Q set by external resistors/capacitors - allows system-specific acoustic tailoring without firmware changes.
Low DC Stepping	<10 mV DC offset shift between adjacent volume/gain steps - prevents audible "thumps" during real-time adjustment.
Input Separation & Channel Isolation	103 dB channel separation and ≥80 dB inter-input isolation - preserves stereo imaging and prevents crosstalk in multi-source switching.

Applications

Car Audio Head Unit

Hi-Fi Preamp with Source Switching

Use Scenario: Integrated infotainment system with AM/FM tuner, CD player, Bluetooth audio, and auxiliary inputs.

IC Role / Device Role / Timing Role: Central audio routing and conditioning IC - selects active source, applies gain compensation, adjusts tone/balance/fader, and drives amplifier inputs.

Use Value: Eliminates discrete op-amp networks and mechanical potentiometers; enables software-defined audio profiles and factory calibration via I²C.

Use Scenario: High-end stereo preamplifier supporting turntable, DAC, streamer, and tape deck inputs.

IC Role / Device Role / Timing Role: Analog signal processor handling input gain matching, tone shaping, and balanced output drive before power amplification.

Use Value: Delivers 106 dB SNR and 0.01% THD - meets RIAA playback fidelity requirements while enabling remote-controlled tone presets.

Aftermarket Amplifier Controller

Multi-Zone Home Audio Distribution

Use Scenario: External DSP add-on module for legacy car amplifiers lacking digital control.

IC Role / Device Role / Timing Role: Signal conditioner between head unit and amplifier - adds fader/balance, speaker-level attenuation, and mute sequencing.

Use Value: Enables retrofit of modern zone control into older vehicles using only analog interconnects and I²C command lines.

Use Scenario: Whole-house audio system distributing stereo content to four rooms with independent volume per zone.

IC Role / Device Role / Timing Role: Quad-speaker attenuator and source selector - routes one stereo source to four amplified zones with independent level control.

Use Value: Provides hardware-level attenuation (not digital scaling) - preserves dynamic range and avoids quantization noise in distributed analog paths.

Equivalent & Alternatives

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

Alternative Part	Technical Difference	Application Difference	Selection Advice
TDA7388	Integrated 4×45 W Class AB amplifier + built-in audio processor; no external speaker attenuators; higher supply current (12 mA vs. 8 mA).	Replaces separate preamp + power amp stages; not suitable where external amplifiers are used.	Select when board space and BOM count must be minimized and integrated amplification is acceptable.
CS4272-CZZ	24-bit stereo DAC + analog volume/tone control; I²S/PCM interface; no analog input multiplexing or speaker-level outputs.	Requires upstream ADC for analog source support; targets digital-first architectures.	Select for systems with digital audio sources (e.g., USB audio, SPDIF) and no need for analog input switching.

Compared with TDA7318D, TDA7388 integrates power amplification but sacrifices flexibility in external amp interfacing, while CS4272-CZZ offers higher-resolution digital processing but lacks analog input multiplexing and speaker-level attenuation - making TDA7318D uniquely suited for analog-source-rich, amplifier-agnostic audio routing.

Availability

TDA7318D is available at Aetrix Electronics and suitable for car radio head units, Hi-Fi preamplifiers, aftermarket amplifier controllers, and multi-zone home audio distribution systems requiring stable component supply and long-lifecycle support.

Supply support for TDA7318D 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-grade ICs with ISO/TS 16949 certified manufacturing.

The TDA7318D belongs to ST's automotive audio processor product line, designed specifically for cost-sensitive, high-SNR analog signal routing and conditioning in 12 V vehicle environments - emphasizing robustness, low distortion, and I²C configurability.

FAQ

What is the I²C address of the TDA7318D and how is it configured?

The TDA7318D has a fixed 7-bit I²C slave address of 0x40 (10001000 binary), with the R/W bit appended during transmission. No external address pins or jumpers are present - configuration is solely via the 8-bit register map defined in the datasheet. The device acknowledges all bytes sent to this address and requires no pull-up voltage translation for 5 V systems.

Can the TDA7318D drive headphones directly?

No, the TDA7318D is not designed for direct headphone driving. Its outputs (OUT(L)/OUT(R) and SPKR ATT pins) are line-level (2.5 Vrms max) with 75 Ω typical output impedance and require external amplification. Driving headphones would risk insufficient current delivery, poor damping factor, and potential DC offset damage to sensitive transducers.

How does the input gain selection affect THD performance?

Input gain selection does not degrade THD: the TDA7318D maintains 0.01% typical THD across its full 0–18.75 dB gain range when driven within its 2 Vrms clipping limit. This is achieved through matched bipolar/CMOS gain cells and low-noise op-amp topology - verified in the datasheet's THD vs. gain plots (Fig. 3 and Fig. 5).

Is the SO28 package of the TDA7318D pin-for-pin compatible with the DIP28 version?

Yes - the SO28 and DIP28 packages share identical pin numbering and function mapping per the top-view diagrams in the datasheet. However, SO28 requires reflow soldering and has different thermal resistance (85°C/W vs. 65°C/W for DIP28), so PCB layout and thermal management must be adapted accordingly.

TDA7318D 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 ~ 10V

Operating Temperature:: -40°C ~ 85°C (TA)

Specifications:: 1.25dB

Mounting Type:: Surface Mount

Grade:: Automotive

TDA7318D FAQ

1.How can I place an order for TDA7318D through Aetrix?

Please submit a Request for Quotation (RFQ) for TDA7318D 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 TDA7318D reliable?

The price and inventory of TDA7318D are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for TDA7318D is usually 5 days.

3.What payment methods are accepted for TDA7318D?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for TDA7318D transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for TDA7318D?

TDA7318D orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your TDA7318D 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 TDA7318D?

For technical support, including TDA7318D datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your TDA7318D requirements.

6.How does Aetrix verify that TDA7318D is sourced from the original manufacturer or authorized distributors?

All TDA7318D 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 TDA7318D meets industry standards.

7.What is the process for return or replacement of TDA7318D?

All TDA7318D units undergo pre-shipment inspection (PSI). If there is an issue with TDA7318D, 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 TDA7318D part is unused and in its original packaging.

Return procedure for TDA7318D:

1.Submit a request within 90 days.

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

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