LT3010/LT3010-5
13
30105fe
Figure 5. Reverse Output Current
OUTPUT VOLTAGE (V)
100
90
80
70
60
50
40
30
20
10
0
REVERSE OUTPUT CURRENT (µA)
30105 F05
0 1 2 3 4 5 6 7 8 9 10
T
A
= 25°C
V
IN
= 0V
CURRENT FLOWS
INTO OUTPUT PIN
V
OUT
= V
ADJ
(LT3010)
V
OUT
= V
SENSE
(LT3010-5)
LT3010
LT3010-5
ADJ
PIN CLAMP
(SEE ABOVE)
APPLICATIONS INFORMATION
In circuits where a backup battery is required, several
different input/output conditions can occur. The output
voltage may be held up while the input is either pulled
to ground, pulled to some intermediate voltage, or is left
open circuit. Current flow back into the output will follow
the curve shown in Figure 5. The rise in reverse output
current above 7V occurs from the breakdown of the 7V
clamp on the ADJ pin. With a resistor divider on the
regulator output, this current will be reduced depending
on the size of the resistor divider.
When the IN pin of the LT3010 is forced below the OUT
pin or the OUT pin is pulled above the IN pin, input cur-
rent will typically drop to less than 2µA. This can happen
if the input of the LT3010 is connected to a discharged
(low voltage) battery and the output is held up by either
a backup battery or a second regulator circuit. The state
of the SHDN pin will have no effect on the reverse output
current when the output is pulled above the input.
