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TLV758P

SBVS351 – APRIL 2018

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Copyright © 2018, Texas Instruments Incorporated

Feature Description (continued)

(1)

All table conditions must be met.

(2)

The device is disabled when any condition is met.

7.3.3 Internal Foldback Current Limit

The TLV758P has an internal current limit that protects the regulator during fault conditions. The current limit is a

approaches GND. When the output is shorted, the LDO supplies a typical current of 350 mA. The output voltage

is not regulated when the device is in current limit. When the device output is shorted, the PMOS pass transistor

cools down, the internal thermal shutdown circuit turns the device back on. If the fault condition continues, the

device cycles between current limit and thermal shutdown.

The foldback current-limit circuit limits the current allowed through the device to current levels lower than the

current load during startup, or if the output voltage is negative when the device is enabled, then the load current

demanded by the load may exceed the foldback current limit and the device may not rise to the full output

voltage. For constant-current loads, disable the output load until the TLV758P has fully risen to its nominal output

voltage.

The TLV758P PMOS pass element has an intrinsic body diode that conducts current when the voltage at the

OUT pin exceeds the voltage at the IN pin. Do not force the output voltage to exceed the input voltage because

excessively high current may flow through the body diode.

7.3.4 Thermal Shutdown

Thermal shutdown protection disables the output when the junction temperature rises to approximately 170°C.

Disabling the device eliminates the power dissipated by the device, allowing the device to cool. When the

junction temperature cools to approximately 155°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 regulator dissipation, protecting the LDO from damage as a result of overheating.

Activating the thermal shutdown feature usually indicates excessive power dissipation as a result of the product

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.

The TLV758P internal protection circuitry protects against overload conditions but is not intended to be activated

in normal operation. Continuously running the TLV758P into thermal shutdown degrades device reliability.

7.4 Device Functional Modes

Table 1 lists a comparison between the normal, dropout, and disabled modes of operation.

Table 1. Device Functional Modes Comparison

OPERATING MODE

PARAMETER

EN

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