Datasheet

TPS2543
SLVSBA6 –FEBRUARY 2012 www.ti.com
Undervoltage Lockout (UVLO)
The undervoltage lockout (UVLO) circuit disables the power switch until the input voltage reaches the UVLO turn-
on threshold. Built-in hysteresis prevents unwanted oscillations on the output due to input voltage drop from large
current surges.
Thermal Sense
The TPS2543 protects itself with two independent thermal sensing circuits that monitor the operating temperature
of the power distribution switch and disables operation if the temperature exceeds recommended operating
conditions. The device operates in constant-current mode during an over-current condition, which increases the
voltage drop across power switch. The power dissipation in the package is proportional to the voltage drop
across the power switch, so the junction temperature rises during an over-current condition. The first thermal
sensor turns off the power switch when the die temperature exceeds 135°C and the part is in current limit. The
second thermal sensor turns off the power switch when the die temperature exceeds 155°C regardless of
whether the power switch is in current limit. Hysteresis is built into both thermal sensors, and the switch turns on
after the device has cooled by approximately 20°C. The switch continues to cycle off and on until the fault is
removed. The open-drain false reporting output FAULT is asserted (active low) during an over-temperature
shutdown condition.
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