Audio Amps Work Inside To Boost Performance Of Mics

Designed to be integrated directly inside 2- and 3-wire electret condenser microphones (ECMs), the LMV1012/1014 audio amplifiers have been developed to replace junction field-effect transistor (JFET) amps currently used in the microphones, with the replacement said to boost the mic’s sensitivity, noise immunity, and audio performance. These first “amp-in-a-mic” ICs are targeted for use in microphones found in mobile headsets, PDAs, and other portables. Supporting two-pin mic designs, the LMV1012 audio amp is ideally suited for use where high signal integrity must be maintained in the presence of ambient or RF noise. It operates from a 2.2V to 5.0V supply with a mixed gain of 15.6 dB and costs $0.39 each/1,000 in a 4-bump micro SMT package. Operating from a 1.7V to 5V supply, with fixed voltage gain of 6 dB, supply current of just 38 µA, and an output impedance of 200?, the LMV1014 is for use in 3-wire mics and costs $0.49 in the 4-bump package. NATIONAL SEMICONDUCTOR CORP., Design Support Group, Santa Clara, CA. (800) 272-9959.