P =(V

V

)I

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D

IN

OUT

OUT

TLV1117LV Series

www.ti.com

SBVS160A

– MAY 2011 – REVISED SEPTEMBER 2011

Undervoltage Lockout (UVLO)

The TLV1117LV uses an undervoltage lockout circuit keep the output shut off until internal circuitry operating

properly.

Thermal Information

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, junction temperature should be limited 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 TLV1117LV has been designed to protect against overload conditions. It

was not intended to replace proper heatsinking. Continuously running the TLV1117LV into thermal shutdown

degrades device reliability.

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

Dissipation Ratings 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 heatsink effectiveness.

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

(1)

Package Mounting

Current solder pad footprint recommendations for the TLV1117LV are available from the Texas Instruments web

site at www.ti.com. The mechanical drawing for the DCY (SOT223) package and the recommended land pattern

for the DCY (SOT223) package are both appended to this data sheet.

Copyright

© 2011, Texas Instruments Incorporated

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