FEATURES

234· 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 = 150Ω

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

DESCRIPTION

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.SoundPlus?

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.