The document describes the features and characteristics of the PGA2500 digitally controlled analog microphone preamplifier, including fully differential input-to-output architecture, digitally controlled gain, dynamic performance, zero crossing detection, integrated DC servo, and common-mode servo.
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). It features a fully differential input-to-output architecture and a gain range of 10dB through 65dB in 1dB steps, with a unity gain setting available via a serial port or dedicated control pin.
The device includes a four-wire serial control port interface that supports daisy-chaining of multiple PGA2500 devices. Key features include zero crossing detection to minimize audible artifacts during gain switching, an integrated DC servo to minimize output offset voltage, and a common-mode servo to improve CMRR. The PGA2500 requires +5V and -5V power supplies and is available in an SSOP-28 package.
| Gain Range | 10dB through 65dB |
|---|---|
| Gain Step Size | 1dB per step |
| Equivalent Input Noise | -128dBu |
| Total Harmonic Distortion plus Noise | 0.0004% |
| Operating Temperature Range | -40 to +85 °C |
| Supply Voltage | +5V and -5V |
| Package Type | SSOP-28 |
| Serial Clock Frequency | 0 to 6.25 MHz |
The gain range is 10dB through 65dB with 1dB per step.
Gain settings and internal functions are programmed using a 16-bit control word loaded via a simple serial port interface.
The device requires both +5V and -5V power supplies.