Datasheet

LM5009
SNVS402G –FEBRUARY 2006–REVISED FEBRUARY 2013 www.ti.com
An external re-circulating diode (D1) carries the inductor current after the internal buck switch turns off. This
diode should be of the ultra-fast or Schottky type to minimize turn-on losses and current over-shoot.
Thermal Protection
The LM5009 should be operated so the junction temperature does not exceed 125°C during normal operation.
An internal Thermal Shutdown circuit is provided to protect the LM5009 in the event of a higher than normal
junction temperature. When activated, typically at 165°C, the controller is forced into a low power reset state,
disabling the buck switch. This feature prevents catastrophic failures from accidental device overheating. When
the junction temperature reduces below 140°C (typical hysteresis = 25°C), the buck switch is enabled, and
normal operation is resumed.
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