LT3050 datasheet(22/26 Pages) LINER

22 / 26 page

LT3050 Series

3050fa

Figure 7. Reverse Output Current

VOUT (V)

1.0

0.3

0.6

0.7

0.8

0.9

0.4

0.5

0.1

0.2

3050 F07

1020304050

ALL PINS GROUNDED EXCEPT FOR OUT

The LT3050 IN pin withstands reverse voltages of 50V. The

device limits current ﬂow to less than 300μA (typically less

than 10μA) 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 ﬂows through the pass transistor from the output.

However, current ﬂows in (but is limited by) the resistor

divider that sets the output voltage. Current ﬂows 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.

LT3050 Datasheet(PDF) 22 Page - Linear Technology