ON Semiconductor Introduces High Quality Class AB Audio Amplifier for Portable and Wireless Applications

“Having a clear, noise-free audio output is crucial to the user’s satisfaction of a cell phone or portable media device,” said Manor Narayanan, vice president and general manager of ON Semiconductor’s Digital and Consumer Products Group. “Hardware designers, however, typically encounter unexpected noise issue coming from the audio system. ON Semiconductors new Class AB amplifier ensures noise-free amplification and is resistive to external noise sources so it guarantees a high quality audio performance. By enforcing our amplifier’s robustness, we expect to minimize the audio designer’s effort and design cycle time.”

The NCP2991 addresses two of the most crucial requirements in today’s portable and wireless audio applications, namely customer demand for noise-free audio amplification and fast response time.

Noise-free audio amplification

NCP2991 offers a superior Power Supply Rejection Ratio (PSRR) of -103 decibels (dB) that eliminates any noise that may be generated by the fluctuation of battery supply voltage. The device is highly resistive to the so-called “TDMA noise” (Time Division Multiple Access) that occurs during the Global System Mobile (GSM) transmission. Additionally, the device guarantees zero pop-and-click noise at start-up and shut-down, which apply to all input configurations. Its very low typical Total Harmonic Distortion (THD) level (0.015 percent) further ensures high fidelity audio output.

Ultra fast start-up time

The start-up time of NCP2991 is selectable between 15 milliseconds (ms) and 20 milliseconds (ms). Thanks to this very fast start-up time, the NCP2991 can be kept in shut-down mode when it is not in use. Therefore, most of the time, the NCP2991 consumes only 20 nanoamps (nA). Fast audio response is especially crucial for portable devices with touch screen, since the audio feedback is perceived by end-user as the indication of the total system’s responsiveness.

Additional Features

The NCP2991 is capable of delivering 1.35 watts (W) of output power to an 8 ohm speaker, or 1.1 W to a 4 ohm speaker. It also has built-in thermal overload protection circuitry to disable the device’s operation in case of an over-temperature situation.

“The NCP2991 is a key addition to ON Semiconductor’s portfolio of solutions targeted at the four primary subsystems typically found in most portable applications.” said Wes Reid, ON Semiconductor director of strategic marketing and systems engineering for Digital Consumer products. “This device specifically addresses needs within the Audio subsystem. ON Semiconductor also offers solutions for the lighting/display, the power management and the interconnect subsystems found in handheld and portable devices.”