Mixed Signal/Analog

Nuvoton Introduces Ultra-Low-Power, Filter-Free 3.1W Class-D Audio Amplifiers

26th October 2012
ES Admin
Nuvoton Technology today introduced a family of new Class-D audio amplifiers designed to optimize portable consumer devices. The new Nuvoton NAU8223 and NAU8224 feature high-efficiency stereo, analog input 3.1W Class-D power amplifiers - ideal for mobile consumer electronics such as smart phones, tablet PC, docking stations, portable audio and video players, LCD and LED TVs, and toys.
Lowering both power and noise are essential in the fast-moving, highly competitive market for consumer and portable devices,” said Jae-Hong Oh, senior product marketing manager at Nuvoton. “Our engineers, therefore, spearheaded an intensive effort to define a new generation of Class-D amplifiers -- the NAU8223 and NAU8224 -- designed to address the market’s need for power consumption and reduced switching noise, while delivering an array of other experience-enriching features.”

The NAU8223 and NAU8224 stereo Class-D audio amplifiers set a new standard in audio amplifiers by offering an ultra-low quiescent current (2.1mA at 3.7V for two channels) for output power delivered, making the devices ideal for the portable applications where battery life represents a significant differentiating factor. The two new amplifiers’ inputs can be configured in either single-ended or differential mode. Neither the NAU8223 nor NAU8224 amplifiers need an external output filter, as each reduces electromagnetic interference (EMI) through spread-spectrum-oscillator technology and slew-rate control. Moreover, the NAU8223 and NAU8224 provides improved immunity and power supply rejection ratio, or PSRR, of > 85dB at 217Hz, making the devices ideal Class-D audio amplifiers for wireless and AM frequency band applications.

Leap Forward in Efficiency, Power

The Class D topology represents a significant leap forward in both power efficiency and noise minimization in audio devices. Class D amplifiers generate a square wave, making the wave-form binary so that it can be amplified by switching the power devices. The power efficiencies of Class D amplifiers are two-thirds better than those of Class AB devices.


The Class D NAU8223 and NAU8224 are capable of driving a 4Ω load with up to 3.1W output power, and feature a chip-enable pin for extremely low standby current and fast start-up time of 3.4ms. The NAU8223 has five selectable gain settings, between 0dB and 24dB, which can be controlled by a single gain pin. The NAU8224 features a highly flexible two-wire interface with gain settings from 24dB to -62dB (plus mute).

For more information on the new NAU8223 and NAU8224 Class D amplifiers, along with Nuvoton’s entire line of audio amplifiers – click here.

Availability, Pricing

Both the NAU8223 and NAU8224 are sampling now in a 20-pin QFN package. The NAU8223 is priced at $0.40, the NAU8224 at $0.50 (for quantities of 1,000 or more).

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