Tiny Amps Drive Ceramic Speakers

Heralded as the industry’s smallest cer-amic-speaker drivers, the LM4962 and LM4953, predict credit-card-thin handsets or additional features for existing designs without consuming extra space and power. Measuring 5 mm2, the LM4962 integrates a boost converter with an audio power amplifier for mono applications. For stereo, the boost converter drives a second external amplifier. The device delivers 15Vp-p across a BTL with less than 1% THD+N from a 3.2V supply. Other features include over-current protection for the boost converter and over-voltage protection. The 3 mm x 4 mm LM4953 is the company’s first audio amp to use a charge pump to drive speakers and requires only eight external components. It provides a 12.6 Vp-p output across a 2 µF plus 30? BTL with less than 1% THD+N. Prices for the LM4962 in a 28-bump SMD package and LM4953 in a14-pin LLP are $2.50 and $1.85 each/1,000, respectively. NATIONAL SEMICONDUCTOR CORP., Santa Clara, CA. (800) 272-9959.