LT3050 Series
22
3050fa
Figure 7. Reverse Output Current
V
OUT
(V)
I
OUT
(µA)
1.0
0.3
0.6
0.7
0.8
0.9
0.4
0.5
0.1
0.2
3050 F07
0
0 1020304050
ALL PINS GROUNDED EXCEPT FOR OUT
The LT3050 IN pin withstands reverse voltages of 50V. The
device limits current fl ow to less than 300A (typically less
than 10A) and no negative voltage appears at OUT. The
device protects both itself and the load against batteries
that are plugged in backwards.
The SHDN pin cannot be driven below GND unless tied
to the IN pin. If the SHDN pin is driven below GND while
IN is powered, the output may turn on. SHDN pin logic
cannot be referenced to a negative rail.
The LT3050 incurs no damage if its output is pulled be-
low ground. If the input is left open-circuit or grounded,
APPLICATIONS INFORMATION
the output can be pulled below ground by 50V. No cur-
rent fl ows through the pass transistor from the output.
However, current fl ows in (but is limited by) the resistor
divider that sets the output voltage. Current fl ows from
the bottom resistor in the divider and from the ADJ pin’s
internal clamp through the top resistor in the divider to
the external circuitry pulling OUT below ground. If the
input is powered by a voltage source, the output sources
current equal to its current limit capability and the LT3050
protects itself by thermal limiting. In this case, grounding
the SHDN pin turns off the device and stops the output
from sourcing current.
