Datasheet

LT3090
21
3090fa
For more information www.linear.com/LT3090
applicaTions inForMaTion
applied and input voltage rises, the output follows the input
and keeps the output-to-input differential low to allow the
regulator to supply large output current and startup into
high current loads.
Due to current limit fold back, however, at high input volt
-
ages, a
problem can occur if the output voltage is low and
the
load current is high. Such situations occur after the
removal of a short-circuit or if the shutdown pin is pulled
high after the input voltage has already turn ON. The load
line for such a load intersects the output current curve at
two points. If this happens, the regulator has two stable
output operating points. With this double intersection, the
input power supply may need to be cycled down to zero
and brought back up again to make the output recover.
Other LT C negative linear regulators such as the LT3015,
LT1964, and LT1175 also exhibit this phenomenon, so it
is not unique to the LT3090.
Protection Features
The LT3090 incorporates several protection features that
make it ideal for use in battery-powered applications. In
addition to the normal protection features associated
with monolithic regulators, such as current limiting
and
thermal
limiting, the device also protects itself against
reverse output voltages.
Precision current limit and thermal overload protection
protect the LT3090 against overload and fault conditions
at the device’s output. For normal operation, do not al
-
low the junction temperature to exceed 125°C for E- and
I-grades and 150°C for H- and MP-grades.
Pulling the LT3090’s output above ground induces no
damage to the part. If IN is left open circuited or grounded,
OUT can be pulled 36V above GND. In this condition, a
maximum current of 7mA flows into the OUT pin and out
of the GND pin. If IN is powered by a voltage source, OUT
sinks the LT3090’s (fold back) short-circuit current and
protects itself by thermal limiting. In this case, however,
grounding the SHDN pin turns off the device and stops
OUT from sinking the short-circuit current.
Downloaded from Arrow.com.Downloaded from Arrow.com.Downloaded from Arrow.com.Downloaded from Arrow.com.Downloaded from Arrow.com.Downloaded from Arrow.com.Downloaded from Arrow.com.Downloaded from Arrow.com.Downloaded from Arrow.com.Downloaded from Arrow.com.Downloaded from Arrow.com.Downloaded from Arrow.com.Downloaded from Arrow.com.Downloaded from Arrow.com.Downloaded from Arrow.com.Downloaded from Arrow.com.Downloaded from Arrow.com.Downloaded from Arrow.com.Downloaded from Arrow.com.Downloaded from Arrow.com.Downloaded from Arrow.com.