P =(V

V

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I

-

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D

IN

OUT

OUT

15

TLV702-Q1

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SLVSC35D – AUGUST 2013 – REVISED JULY 2019

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Copyright © 2013–2019, Texas Instruments Incorporated

9 Power Supply Recommendations

Connect a low output impedance power supply directly to the IN pin of the TLV702-Q1. Inductive impedances

between the input supply and the IN pin can create significant voltage excursions at the IN pin during start-up or

load transient events.

9.1 Power Dissipation

The ability to remove heat from the die is different for each package type, presenting different considerations in

the printed-circuit-board (PCB) layout. The PCB area around the device that is free of other components moves

the heat from the device to the ambient air.

Refer to Thermal Information for thermal performance on the TLV702-Q1 evaluation module (EVM). The EVM is

a two-layer board with two ounces of copper per side.

Power dissipation depends on input voltage and load conditions. Power dissipation (PD) is equal to the product of

the output current and the voltage drop across the output pass element, as shown in Equation 1.

(1)

10 Layout

10.1 Layout Guidelines

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

as PSRR, output noise, and transient response, design the board with separate ground planes for VIN and VOUT,

with the ground plane connected only at the GND pin of the device. In addition, connect the ground connection

for the output capacitor directly to the GND pin of the device. High-ESR capacitors may degrade PSRR

performance.

10.1.1 Thermal Consideration

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 may 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.

The internal protection circuitry of the TLV702-Q1 is designed to protect against overload conditions but is not

intended to replace proper heatsinking. Continuously running the TLV702-Q1 into thermal shutdown degrades

device reliability.