GND

Represents via used for

application-specific connections

TLV705, TLV705P

www.ti.com

SBVS151E – DECEMBER 2010 – REVISED MAY 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 designing the board with the input and output

capacitors on opposite sides of the device. In addition, connect the ground connection for the output capacitor

directly to the GND pin of the device. High ESR capacitors can degrade PSRR.

10.2 Layout Example

Figure 31. Example PCB Layout

10.3 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. Performance data for JEDEC low and high-K boards are given in the

Thermal Information table. Using heavier copper increases the effectiveness in removing heat from the device.

The addition of plated through-holes to heat-dissipating layers also improves the thermal dissipation.

Refer to the section for thermal performance on the TLV705 evaluation module (EVM). The EVM is a 2-layer

board with 2 ounces of copper per side.

the output current and the voltage drop across the output pass element, as shown in Equation 3:

(3)

10.4 Power Dissipation and Junction Temperature

Thermal protection disables the output when the junction temperature rises to approximately 160°C, allowing the

device to cool. When the junction temperature cools to approximately 140°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.

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

complete design, increase the ambient temperature until the thermal protection is triggered; use worst-case loads

and signal conditions. For good reliability, trigger thermal protection 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 internal protection circuitry of the TLV705 is designed to protect against overload conditions. Continuously

running the TLV705 into thermal shutdown degrades device reliability.

Copyright © 2010–2015, Texas Instruments Incorporated

Submit Documentation Feedback

17

Product Folder Links: TLV705 TLV705P