11.2 Power-Supply Decoupling

Good power-supply decoupling is important to achieve optimum performance. As shown in Figure 27, VDD must be decoupled with at least a 0.1-µF capacitor to GND. The 0.1-µF bypass capacitor supplies the momentary bursts of extra current required from the supply when the device is converting. Place the bypass capacitor as close to the power-supply pin of the device as possible using low-impedance connections. Use multilayer ceramic chip capacitors (MLCCs) that offer low equivalent series resistance (ESR) and inductance (ESL) characteristics for power-supply decoupling purposes. For very sensitive systems, or for systems in harsh noise environments, avoid using vias to connect the capacitors to the device pins for better noise immunity. The use of multiple vias in parallel lowers the overall inductance and is beneficial for connections to ground planes.

Figure 27. TLA202x Power-Supply Decoupling