Audio solution guide for analog home systems Audio processors, Class AB and Class D amplifiers

Leveraging its long experience in audio devices, STMicroelectronics has a wide analog device portfolio that addresses home stereo and multi-channel audio equipment, such as home cinema systems. Our large Class D and Class AB portfolio is recognized by customers worldwide as the most complete offering for analog 2.0/2.1 multi-channel systems. High reliability, outstanding audio quality, turnkey solution support and design resources contribute to our leadership as an analog audio solution provider. This brochure presents a simple selection guide for our analog amplifiers and audio processors to...

Analog audio processors Analog audio processors are designed for controlling more advanced features on home audio systems, such as tone controls, surround mode, voice canceller, input and output multiplexers, bass boost, bass ALC and headphone driving capability. Data transmission between the main application microprocessor and the audio processor is via a 2-wire I2C bus interface. Analog audio processor main features Speaker attenuation Supply voltage min/max [V] Part number Tone control Surround modes Volume control  Number of stereo inputs TDA7469 also drives a stereo headphone

Figure 1 shows a simple example of a stereo analog solution based on the TDA7469 audio processor with headphone drive, with a TDA7492 (2 x 50 W) analog Class D amplifier. Docking stations can be easily addressed with the proposed solution. 6-input L/R volume, treble bass control TDA7492 2 x 50 W stereo Class D audio amplifier Figure 1a. Docking station schema using the TDA7469 audio processor with direct headphone drive and the TDA7492 2 x 50 W high-efficiency Class D audio power amplifier. Half_wave rectifier Figure 1b. TDA7469 technical schematic Figure 1c. TDA7492 technical schematic

Analog audio amplifiers The largest portfolio in the market Our analog amplifier portfolio covers applications ranging from compact home mini-hifi units to very substantial home stereo systems. Mono, stereo, multi-channel, Class AB or Class D, our amplifier family offers devices providing just a few watts of output power, to those pumping out more than 100 W per channel. Our product range also offers features such as: n mute n standby n single- and split supply n variable gain n volume control n BTL (bridge-tied load) and single-ended operation n insertion and SMD packages Safety first All our...

Class AB audio amplifiers Class AB audio amplifiers offer excellent clarity and signal fidelity. Pure analog, this signal quality is paid for with lower power efficiency, relative to Class D amplifiers. Nevertheless, these reliable components offer a warm, full-bodied tone that guarantees their place in the best audio systems available. The TDA729x is recognized as a preferred solution for systems made with audiophiles in mind. Class AB audio amplifier main features Part number Output power per channel [W] 18 Supply voltage min/max [V] STA540: Pout (2 x 26 W, 2 x 12 W + 1 x 26 W, 4 x 12 W) TDA7497:...

THERMAL SHUTDOWN -Vs Note: The Boucherot cell R6, C10, is normally not necessary for a stable operation but could be needed in presence of particular load impedances at VS <±25 V. Figure 3. Typical application schematic suitable for TDA7293, TDA7294, TDA7295 or TDA7296 MUTE PROTECTIONS Figure 4. Typical application schematic suitable for TDA7497, TDA7497S

The flexible solution: STA540/STA540SA The STA540 is a Class AB audio power amplifier that offers extreme flexibilty. This smart device can be used in the following configurations: In addition to offering three output configurations, the STA540 is easy to use and only requires an extremely low component count. DIAGNOSTIC OUTPUT Figure 5. Block diagram for the STA540 P-GND S-GND Figure 6. Three different configurations possible for the STA540 Figure 7. The STA540SA demonstration board for the 2/1 channel configuration

Class D audio amplifiers Class D audio amplifiers can offer greatly increased efficiency compared to Class AB amplifiers due to their circuit topology. Similar in scheme to a switching regulator, a Class D amplifier pulse width modulates the audio input signal with a higher frequency square wave so that the audio signal becomes the variations in pulse width of this modulated signal. The frequency of the PWM oscillator is important as it determines both the output filter requirements and the sampling rate for the audio input. In our Class D amplifiers, the best balance between performance and...

Figures 8 to 11 show typical application circuits and internal block diagrams from most of the Class D amplifiers listed in the table above. J2 SMD Type C20 16 V 10 µF C3 The jumper J5 For single end input Figure 8. Typical application schematic for the TDA7493 Figure 9. Application schematic suitable for the TDA7491LP, TDA7491P, TDA7491HV, TDA7492P and TDA7492 (device shown slug down and pin-mirrored)

Figure 10. Typical application schematic for the TDA7491MV R1 10K Figure 11. Application schematic suitable for the TDA7490 or TDA7490L Figure 12. Evaluation board for TDA7491P Figure 13. Evalution board for TDA7492P

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