PGA2500

The PGA2500 is a digitally controlled, analog microphone preamplifier designed for use as a front end for highperformance audio analog-to-digital (A/D) converters. The PGA2500 features include low noise, wide dynamic range, and a differential signal path. An on-chip DC servo loop is employed to minimize DC offset, while a common-mode servo function may be used to enhance common-mode rejection.

The PGA2500 features a gain range of 10dB through 65dB (1dB/step), along with a unity gain setting. The wide gain range allows the PGA2500 to be used with a variety of microphones. Gain settings and internal functions are programmed using a 16-bit control word, which is loaded using a simple serial port interface. A serial data output pin provides support for daisy-chained connection of multiple PGA2500 devices. Four programmable digital outputs are provided for controlling the external switching of input pads, phantom power, high pass filters, and polarity reversal functions. The PGA2500 requires both +5V and –5V power supplies and is available in a small SSOP-28 package.