ISL78302_14 Datasheet, PDF (11/13 Pages) Intersil Corporation – Dual LDO with Low Noise, High Performance and Low IQ

ISL78302
capacitor connected to the CPOR pin. For a 0.01µF capacitor, the
entry and exit delays are 200ms and 25µs, respectively. Larger
or smaller capacitor values will yield proportionately longer or
shorter delay times. The POR exit delay should never be allowed
to be less than 10µs to ensure sufficient immunity against
transient induced false POR triggering.
Over-Temperature Detection
The bandgap provides a proportional-to-temperature current that
indicates the temperature of the silicon. This current is compared
with references to determine whether the device is in danger of
damage from overheating. When the die temperature reaches
about +145°C, one or both of the LDOs momentarily shuts down
until the die cools sufficiently. In the overheat condition, only the
LDO sourcing more than 50mA is shut off. This shutoff does not
affect the operation of the other LDO. If both LDOs source more
than 50mA and an overheat condition occurs, both LDO outputs
are disabled. Once the die temperature falls back below about
+110°C and disabled LDOs are re-enabled, the soft-start
automatically takes place.
The ISL78302 provides short-circuit protection by limiting the
output current to about 475mA. If short circuited, an output
current of 475mA causes die heating. If the short circuit lasts
long enough, the overheat detection circuit turns off the output.
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FN7696.6
November 6, 2014