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STMicro’s audio amp for mobile equipment differential inputs keeps noise down

Geneva — STMicroelectronics Inc.'s fully differential architecture audio power amplifier is capable of delivering 1.2 W of continuous rms and requires very few external components.

The Class AB TS4994 amplifier, with one differential mono input, is intended for use in mobile phones, laptops, PDAs and portable audio devices.

This fully differential audio power amplifier capable of delivering 1.2 W of continuous rms power into an 8Ω load at 5 V, with a total harmonic distortion of 1%, measured at 1 kHz. The differential design means the part has good noise immunity with an 85dB common mode rejection ratio and 100dB power supply rejection ratio, both at 217 Hz with grounded inputs. The part has also been designed to avoid pops and clicks.

The amplifier runs off a supply of 2.5 V to 5.5 V. It has a standby mode, which can be set by a signal that can be programmed to be active high or low. Standby mode cuts power consumption to 10 nA. This is complemented by an ultra-fast start-up time of 15 ms.

Other features include thermal shutdown protection, to protect against short circuits. Common-mode feedback circuitry enables the outputs to be biased to half the supply voltage, regardless of the input common-mode voltage.

The TS4994 is available in a nine-bump, 0.5mm-pitch flip-chip package; as a DFN10 or as a MiniSO-8 part. Pricing is 60 cents each in 5,000-piece quantities.Click here for the TS4994 data sheet.

STMicroelectronics , 1-781-861-2650, www.st.com.

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