Mic Preamp Provides Digital Control

Introduced as the first digitally controlled microphone pre-amplifier, the PGA2500 is designed for use as a front end for a/d converters in a variety of professional audio applications. The device provides a gain range from 10 dB to 65 dB at 1dB per step, allowing it to be used with a variety of microphones. Gain and functions are programmed using a 16-bit control word that is loaded via a serial port interface. A serial output pin supports daisy-chaining multiple PGA2500 devices. Other features include a dc servo loop to minimize offset, common-mode servo function, and four programmable digital outputs for controlling external switching of input pads, phantom power, high-pass filters, and polarity-reversal functions. Available in a 28-lead SSOP, price is $9.95 each/1,000. TEXAS INSTRUMENTS INC., Dallas, TX. (800) 477-8924.