SBOU259 October   2021 PGA2505

 

  1.   Trademarks
  2. 1Product Overview
  3. 2Features
  4. 3Getting Started
    1. 3.1 Electrostatic Discharge Caution
    2. 3.2 Unpacking the EVM
    3. 3.3 Absolute Maximum Operating Conditions
  5. 4Setup Guide
    1. 4.1 Analog and Digital Power Supplies
    2. 4.2 Microphone Input
    3. 4.3 Phantom Power Connections
    4. 4.4 DC Blocking Capacitors
    5. 4.5 Protection Network
    6. 4.6 Configurable Input Circuitry
    7. 4.7 Configurable Output Circuitry and Preamp Output Connector
  6. 5Software Operation
    1. 5.1 Applications Software Overview
    2. 5.2 Using the GUI
  7. 6Schematic, PCB Layout, and Bill of Materials
    1. 6.1 Schematic
    2. 6.2 PCB Layout
    3. 6.3 Bill of Materials

4.1 Analog and Digital Power Supplies

All analog and digital power supplies are connected through terminal block J2, as shown in Figure 4-1. Recommended power-supply connections are as follows:

  • +VA and –VA are +5 V and –5 V, respectively
  • Connect EGND to earth or chassis ground of the power supply
  • Connect GND to common ground
  • Leave VCC unconnected if using the MSP-EXP430F5529LP
Figure 4-1 Power Terminal Block J2 Schematic

The PGA2505EVMV2 requires two analog supplies and one digital power supply. The analog supplies are VA+ and VA−, respectively. VA+ is typically set to +5.0 VDC, while VA− is typically set to −5.0 VDC. The analog supplies power the PGA2505 microphone preamplifier integrated circuit. The digital power supply, VCC, is unconnected if using the MSP-EXP430F5529LP.

An optional third analog power supply may be used for the PGA2505 common-mode dc voltage input, VCOMIN (pin 22). VCOMIN allows the PGA2505 output and input to be dc biased to a common-mode voltage between 0 V and 2.5 V, and is connected through terminal block J2. The common-mode voltage biases both the output and input terminals of the PGA2505, with the output pins biased to the VCOMIN voltage level and the input pins biased to approximately VCOMIN − 0.65 V.

The GND terminal of connector J2 serves as the common ground connection for both the analog and digital sections of the PGA2505EVMV2. Connect the EGND (earth ground) terminal to the earth or chassis ground of the power supply. The common ground (GND) and earth ground (EGND) are connected to one another using a 0.1-µF capacitor (C10).