PGA2505 - Digitally Controlled Microphone Preamplifier

Texas Instruments' PGA2505 is a lower performance/lower cost follow-on device to the existing PGA2500 digitally controlled, analog microphone preamplifier IC, designed for use as a front end for high performance audio analog to digital converters (ADC's). The PGA2505 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.

Overview

The PGA2505 features a gain range of 9dB through 60dB (3dB/step), along with a unity gain setting. The wide gain range allows the PGA2505 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 PGA2505 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 PGA2505 requires both +5V and -5V power supplies and is available in a small SSOP-24 package.

Diagram