All analog and digital power supplies are connected through terminal block J2, see Figure 4-1. Recommended power-supply connections are described in the following:

• +VA and –VA are +5 V and –5 V
• 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 PGA2500EVMV2 requires two analog supplies and one digital power supply. The analog supplies are VA+ and VA−, respectively. VA+ is typically set to +5.0 V DC, while VA− is typically set to −5.0 V DC. The analog supplies power the PGA2500 microphone preamplifier integrated circuit. The digital power supply, VCC, is left unconnected if using the MSP-EXP430F5529LP.

An optional third analog power supply may be utilized for the PGA2500 common-mode DC voltage input, VCOMIN (pin 25). VCOMIN allows the PGA2500 output and input to be DC biased to a common-mode voltage between 0 and +2.5 V and is connected through terminal block J2. The common-mode voltage biases both the output and input terminals of the PGA2500, with the output pins being biased to the VCOMIN voltage level and the input pins being 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 PGA2500EVMV2. The EGND (earth ground) terminal should be connected 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).