PGA2500 Datasheet, PDF (1/16 Pages) Burr-Brown (TI) – Digitally Controlled Microphone Preamplifier

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
D Dynamic Performance:
− Equivalent Input Noise with Z_S = 150Ω and
Gain = 30dB: −128dBu
− Total Harmonic Distortion plus Noise
(THD+N) with Gain = 30dB: 0.0004%
D Zero Crossing Detection Minimizes Audible
Artifacts when Gain Switching
D Integrated DC Servo Minimizes Output Offset
Voltage
D Common-Mode Servo Improves CMRR
D Four-Wire Serial Control Port Interface:
− Simple Interface to Microprocessor or
DSP Serial Ports
− Supports Daisy-Chaining of Multiple
PGA2500 Devices
D Dedicated Input Pin for Selecting Unity Gain
D Overload Output Pin Provides Clipping
Indication
D Four General-Purpose Digital Output Pins
D Requires ±5V Power Supplies
D 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 high-
performance 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 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.
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