GND PLANE

Represents via used for

application specific connections

1

2

3

4

5

TPS709

www.ti.com

SBVS186G – MARCH 2012 – REVISED NOVEMBER 2015

10 Layout

10.1 Layout Guidelines

Place input and output capacitors as close to the device pins as possible. To improve ac performance (such as

PSRR, output noise, and transient response), TI recommends that the board be designed with separate ground

ground connection for the output capacitor must be connected directly to the device GND pin.

10.1.1 Thermal Protection

Thermal protection disables the output when the junction temperature rises to approximately 165°C, allowing the

device to cool. When the junction temperature cools to approximately 145°C, the output circuitry is again

enabled. Depending on power dissipation, thermal resistance, and ambient temperature, the thermal protection

circuit can cycle on and off. This cycling limits the dissipation of the regulator, protecting it from damage as a

result of overheating.

Any tendency to activate the thermal protection circuit indicates excessive power dissipation or an inadequate

heatsink. For reliable operation, limit junction temperature to 125°C, maximum. To estimate the margin of safety

in a complete design (including heatsink), increase the ambient temperature until the thermal protection is

triggered; use worst-case loads and signal conditions. For good reliability, thermal protection must trigger at least

35°C above the maximum expected ambient condition of the particular application. This configuration produces a

worst-case junction temperature of 125°C at the highest expected ambient temperature and worst-case load.

The TPS709 internal protection circuitry is designed to protect against overload conditions. This circuitry is not

intended to replace proper heatsinking. Continuously running the TPS709 into thermal shutdown degrades

device reliability.

10.2 Layout Example

Figure 39. Layout Example for DBV Package

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Product Folder Links: TPS709