Thermal Pad

(1)

TPS717

www.ti.com

SBVS068H – FEBRUARY 2006 – REVISED JANUARY 2015

10 Layout

10.1 Layout Guidelines

For best overall performance, place all circuit components on the same side of the circuit board and as near as

practical to the respective LDO pin connections. Place ground return connections to the input and output

capacitor, and to the LDO ground pin as close to the GND pin as possible, connected by wide, component-side,

copper surface area. The use of vias and long traces to create LDO component connections is strongly

discouraged and negatively affects 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 printed circuit board (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, shields the LDO from noise, and functions similar to a thermal plane to spread (or sink) heat from

the LDO device when connected to the thermal pad. In most applications, this ground plane is necessary to meet

thermal requirements.

10.1.1 Board Layout Recommendations to Improve PSRR and Noise Performance

To improve ac performance (such as PSRR, output noise, and transient response), TI recommends that the

GND pin of the device. In addition, the ground connection for the bypass capacitor must connect directly to the

GND pin of the device.

10.2 Layout Example

(1)

Circles within thermal pad area indicate vias to other layers on the board, for electrical connections or thermal

conduction.

Figure 37. Fixed Voltage Layout

Copyright © 2006–2015, Texas Instruments Incorporated

Submit Documentation Feedback

19

Product Folder Links: TPS717