To improve ac performance such as PSRR, output noise, and transient response, design the board with separate ground planes for IN and OUT, with each ground plane connected only at the GND pin of the device. In addition, the ground connection for the output capacitor must connect directly to the GND pin of the device.

Equivalent series inductance (ESL) and ESR must be minimized in order to maximize performance and provide stability. Every capacitor must be placed as close as possible to the device and on the same side of the PCB as the regulator.

Do not place any of the capacitors on the opposite side of the PCB from where the regulator is installed. Using vias and long traces is strongly discouraged because these components can impact system performance negatively and even cause instability.

If possible, and to provide the maximum performance denoted in this product data sheet, use the same layout pattern used for the TPS7A16-Q1 evaluation board, available at www.ti.com.

Layout is a critical part of good power-supply design. There are several signal paths that conduct fast-changing currents or voltages that can interact with stray inductance or parasitic capacitance to generate noise or degrade the power-supply performance. To help eliminate these problems, bypass the IN pin to ground with a low-ESR ceramic bypass capacitor with X5R or X7R dielectric.

Acceptable performance can possibly be obtained with alternative PCB layouts; however, the layout and schematic herein have been shown to produce good results and are meant as a guideline.

Figure 8-8 shows the schematic for the suggested layout. Figure 8-9 and Figure 8-10 show the top and bottom printed circuit board (PCB) layers for the suggested layout.