Powerful Ceramic Speaker Driver for Mobile Phones

National Semiconductor has introduced a single-chip Boomer audio power amplifier which it says delivers the industry's highest voltage for driving ceramic speakers used in a wide range of 3V portable devices. Driving the ceramic speaker at higher voltages allows it to produce a higher sound-pressure level (SPL) for applications that require louder sound. The LM48555 drives ceramic speakers in cell phones, smartphones, notebook computers and other small handheld devices.

With a ceramic speaker load equivalent to 1 uF + 20-Ohms, the LM48555 provides a voltage drive of 15.7V peak-to-peak with less than 1 percent total harmonic distortion plus noise (THD+N). In addition, the LM48555's tiny 12-bump micro SMD package has a footprint of 1.5 mm by 2.0 mm, making it possible for manufacturers to create ultra-thin, feature-rich handsets.

Ceramic speakers require higher voltage, but less current compared to traditional moving coil speakers. The primary benefits of ceramic speakers are their thin profile and light weight. Voice coil speakers are typically 4 mm or more in thickness, while ceramic speakers are only 0.7 mm thick and often weigh less than one gram."

Posted to the site on 30th May 2007