lt3060 Linear Technology Corporation, lt3060 Datasheet - Page 16

• Manufacturer Part Number: lt3060
• Description: 45v Vin, Micropower, Low Noise, 100ma Low Dropout, Linear Regulator
• Manufacturer: Linear Technology Corporation

LT3060
APPLICATIONS INFORMATION
The LT3060 incurs no damage if the ADJ pin is pulled
above or below ground by less than 50V. If the input is
left open-circuit or grounded, the ADJ pin performs like
a large resistor (typically 30k) in series with a diode when
pulled below ground and like 30k in series with two diodes
when pulled above ground.
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 left open-
circuit. Current fl ow back into the output follows the curve
shown in Figure 7.
If the LT3060’s IN pin is forced below the OUT pin or the
OUT pin is pulled above the IN pin, input current typically
drops to less than 1μA. This occurs if the LT3060 input is
connected to a discharged (low voltage) battery and either
a backup battery or a second regulator holds up the output.
The state of the SHDN pin has no effect on the reverse
current if the output is pulled above the input.
16
2.0
1.8
1.6
1.4
1.2
1.0
0.8
0.6
0.4
0.2
0
Figure 7. Reverse Output Current
0
T
V
CURRENT FLOWS
INTO OUT PIN
V
J
IN
OUT
= 25°C
5
= 0V
= V
10
ADJ
OUTPUT VOLTAGE (V)
15
20
ADJ
OUT
25
30
35
40
3060 F07
45
3060f