PGA2500

PGA2500 SBOS289A − NOVEMBER 2003 − REVISED DECEMBER 2003 Digitally Controlled Microphone Preamplifier FEATURES D Fully Differential Input-to-Output Architecture D Digitally Controlled Gain Using Serial Port Interface: − Gain Range: 10dB through 65dB, 1dB per step − Unity (0dB) Gain Setting via Serial Port or Dedicated Control Pin Dynamic Performance: − Equivalent Input Noise with ZS = 150Ω and Gain = 30dB: −128dBu − Total Harmonic Distortion plus Noise (THD+N) with Gain = 30dB: 0.0004% Zero Crossing Detection Minimizes Audible Artifacts when Gain Switching Integrated DC Servo Minimizes Output Offset Voltage Common-Mode Servo Improves CMRR Four-Wire Serial Control Port Interface: − Simple Interface to Microprocessor or DSP Serial Ports − Supports Daisy-Chaining of Multiple PGA2500 Devices Dedicated Input Pin for Selecting Unity Gain Overload Output Pin Provides Clipping Indication Four General-Purpose Digital Output Pins Requires ±5V Power Supplies Available in an SSOP-28 Package APPLICATIONS D Microphone Preamplifiers and Mixers D Digital Mixers and Recorders DESCRIPTION The PGA2500 is a digitally controlled, analog microphone preamplifier designed for use as a front end for highperformance audio analog-to-digital converters (ADCs). 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 ...