The PGA2505 is a digitally-controlled, analog microphone preamplifier designed for use as a front-end for high-performance audio analog-to-digital converters (ADCs). 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.

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, and high-pass filters. The PGA2505 requires both +5V and -5V power supplies and is available in a small SSOP-24 package.

• FULLY DIFFERENTIAL lNPUT-TO-OUTPUT ARCHITECTURE
• DIGITALLY-CONTROLLED GAIN USING SPI™:
  • Gain Range: 9dB through 60dB, 3dB per Step
  • Unity (0dB) Gain Setting via Serial Port
• DYNAMIC PERFORMANCE:
  • Equivalent Input Noise with ZS = 150 and Gain = 30dB: -123dBu
  • Total Harmonic Distortion plus Noise (THD+N) with Gain = 30dB: 0.0006%
• 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 PGA2505 Devices
• OVER-RANGE OUTPUT PIN PROVIDES CLIPPING INDICATION
• FOUR GENERAL-PURPOSE DIGITAL OUTPUT PINS
• ±5V POWER SUPPLIES
• AVAILABLE IN AN SSOP-24 PACKAGE
• APPLICATIONS
  • MICROPHONE PREAMPLIFIERS AND MIXERS
  • DIGITAL MIXERS AND RECORDERS
  • DIGITAL AUDIO EDITING SYSTEMS
  • BROADCAST EQUIPMENT
  • INTERCOMS

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