PGA2500I

Part: PGA2500IDBR — Texas Instruments

Type: Digitally Controlled Microphone Preamplifier

Description: Fully differential, digitally controlled microphone preamplifier with 10–65 dB gain in 1 dB steps, -128 dBu equivalent input noise (30 dB gain, ZS = 150 Ω), and 0.0004% THD+N at 30 dB gain, running from ±5 V supplies.

Operating Conditions:

• Supply voltage: VA+ +4.75 to +5.25 V; VA- and VD- -4.75 to -5.25 V
• Operating temperature: -40 to +85 °C
• Serial clock frequency: 0 to 6.25 MHz
• Output load: 600 Ω minimum

Absolute Maximum Ratings:

• Supply voltage VA+: +5.5 V
• Supply voltage VA-: -5.5 V
• Supply voltage VD-: -5.5 V
• VA- to VD- voltage difference: less than 300 mV
• Analog input voltage: (VA-) -0.3 to (VA+) +0.3 V
• Digital input voltage: -0.3 to (VA+) +0.3 V
• Storage temperature: -60 to +150 °C

Key Specs:

• Gain range: 10 to 65 dB, 1 dB step; gain error typ 0.5 dB (all gain settings)
• THD+N (1 kHz, VOUT = 3.5 VRMS): typ -114 dB at 0 dB gain, typ -108 dB at 30 dB gain (max -108 dB and -102 dB respectively)
• Input impedance: 4600 Ω per input pin, 9200 Ω differential (typ)
• Output offset voltage (DC servo on): ±0.04 mV typ, ±1 mV max
• Output voltage range (RL = 600 Ω): (VA-) +0.9 V to (VA+) -0.9 V
• Short-circuit current: 100 mA typ (10 s duration)
• Quiescent current: IA+ 30 mA typ (40 mA max); IA- 30 mA typ (40 mA max); ID- 1 mA typ (2 mA max)
• Digital inputs: VIH min 2.0 V, VIL max 0.8 V; input leakage 2 μA typ (10 μA max)

Features:

• Fully differential input-to-output architecture
• Serial port gain control, with a dedicated pin for unity (0 dB) gain
• Zero-crossing detection minimizes audible artifacts when gain switches (up to 16 ms detector timeout)
• Integrated DC servo minimizes output offset
• Common-mode servo improves CMRR
• Four-wire serial interface with daisy-chain support for multiple devices
• Overload output pin (OVR) indicates clipping, with a programmable threshold
• Four general-purpose digital outputs for external switching (pads, phantom power, filters, polarity)
• VCOMIN input sets output and input DC bias from 0 to +2.5 V

Applications:

• Microphone preamplifiers and mixers
• Digital mixers and recorders

Package:

• SSOP-28 (DB), supplied as tape and reel, 1000 units (PGA2500IDBR)

• 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 = 150 Ω 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

Please be aware that an important notice concerning availability, standard warranty, and use in critical applications of T exas Instruments semiconductor products and disclaimers thereto appears at the end of this data sheet.

www.ti.com PGA2500

SBOS289A - NOVEMBER 2003 - REVISED DECEMBER 2003

• D Microphone Preamplifiers and Mixers
• D Digital Mixers and Recorders

www.ti.com www.ti.com

All parameters specified with T A = +25 ° C, VA+ = +5V, VA- = -5V, VD- = -5V, and V COMIN = 0V, unless otherwise noted .

Over operating free-air temperature range unless otherwise noted (1)

This section provides practical information for designing the PGA2500 into end applications.