SLVS338R May 2001 – April 2015 TPS715
For best overall performance, place all circuit components on the same side of the printed-circuit-board and as near as practical to the respective LDO pin connections. Place ground return connections for the input and output capacitors as close to the GND pin as possible, using wide, component-side, copper planes. TI strongly discourages using vias and long traces to create LDO circuit connections to the input capacitor, output capacitor, or the resistor divider because that will negatively affect system performance. This grounding and layout scheme minimizes inductive parasitics, and thereby reduces load-current transients, minimizes noise, and increases circuit stability. A ground reference plane is also recommended and is either embedded in the PCB itself or located on the bottom side of the PCB opposite the components. This reference plane serves to assure accuracy of the output voltage and shield the LDO from noise.
To ensure reliable operation, worst-case junction temperature should not exceed 125°C. This restriction limits the power dissipation the regulator can handle in any given application. To ensure the junction temperature is within acceptable limits, calculate the maximum allowable dissipation, PD(max), and the actual dissipation, PD, which must be less than or equal to PD(max).
The maximum-power-dissipation limit is determined using Equation 4:
The regulator dissipation is calculated using Equation 5:
For a higher power package version of the TPS715, see the TPS715A.