11.1.3 Board Layout Recommendations to Improve PSRR and Noise Performance
To improve AC performance such as PSRR, output noise, and transient response, TI recommends to design the board with separate ground planes for VIN and VOUT, 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 ensure stability. Every capacitor must be placed as close to the device as possible 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. The use of vias and long traces is strongly discouraged because of the negative impact on system performance. Vias and long traces can also cause instability.
If possible, and to ensure the maximum performance listed in this data sheet, use the same layout pattern used for TPS7B67xx-Q1 evaluation board, available at www.ti.com.