STMicroelectronics - First Single-Chip Audio Subsystem Featuring 3D-Sound Enhancement

The TS4982’s 3D sound-enhancement circuitry allows closely spaced speakers to deliver greater stereo spatial effects. This enables small devices to deliver a more satisfying, high-quality listening experience for users. The 3D effect is adjustable for low, medium or high volume levels, allowing equipment designers to optimize stereo enhancement according to the type and size of product. The level is set using two external pins on the device, and requires no additional circuitry.

“Consumers are demanding better stereo-sound quality from their portable computing and multimedia devices, which are becoming smaller and smaller,” said Michel Bendridi, Technical Marketing for Audio Products, for ST’s Analog and Mixed-Signal Products Business Unit. “To deliver the high-quality sound consumers require in new and innovative small form-factor products, leading computing and consumer manufacturers will need to incorporate chips like the TS4982 that offer highly integrated advanced 3D audio technology, at consumer price points.”

As an audio subsystem the TS4982 matches or exceeds the capabilities of competing devices: it includes a 2 x 2W stereo speaker driver; a 125mW stereo headphone driver; four-step digital volume control; pop-and-click reduction circuitry to attenuate unwanted system noises; and PC-beep pass-through capability. Separate Enable signals for the headphone and speaker drivers allow the lowest possible power consumption at all times, enabling battery-powered devices to operate for longer. The device also draws very low current of 10nA in shutdown mode, which minimizes the audio subsystem’s effect on battery life when not being used.

In addition to offering enhanced audio capabilities, the TS4982 also helps designers save pc-board space through features such as ground-referenced circuitry for the headphone driver. This avoids the need to add DC-blocking capacitors, thereby reducing overall system size and cost. Since DC-blocking capacitors also represent a source of noise, removing these also contributes to higher audio quality. In addition, the device’s speaker driver has a Bridge-Tied Load (BTL) output, which produces high audio power as well as high efficiency.

The device’s external PC-Beep input allows PC-generated sounds such as power-up self-test codes to be transmitted through the speaker or headphone driver circuitry. In PC-multimedia applications, this allows the user to stay informed of PC status while playing back local or online content.