LT3060EDC 查看數據表（PDF） - Linear Technology
零件编号
产品描述 (功能)
比赛名单
LT3060EDC Datasheet PDF : 26 Pages
| |||
LT3060 Series
Applications Information
The LT3060 IN pin withstands reverse voltages up to 50V.
The device limits current flow to less than 300µA (typi-
cally less than 50µA) 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 supply voltage.
The LT3060 incurs no damage if its output is pulled be-
low ground. If the input is left open-circuit or grounded,
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 LT3060
protects itself by thermal limiting. In this case, grounding
the SHDN pin turns off the device and stops the output
from sourcing current.
The LT3060 incurs no damage if the ADJ pin is pulled
above or below ground by less than 50V. For the adjust-
able version, 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 flow back into the output follows the curve
shown in Figures 7 and 8.
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.
2.0
TJ = 25°C
1.8 VIN = 0V
1.6
CURRENT FLOWS
INTO OUT PIN
1.4 VOUT = VADJ
1.2
1.0
ADJ
0.8
0.6
0.4
0.2
0
0
OUT
5 10 15 20 25 30 35 40 45
OUTPUT VOLTAGE (V)
3060 F07
Figure 7. LT3060 Reverse Output Current
350
TJ = 25°C
300 VIN = 0V
LT3060-1.2
LT3060-1.5
250
LT3060-1.8
200
LT3060-2.5
150
LT3060-3.3
100
50
LT3060-5
0
0 5 10 15 20 25 30 35 40 45
OUTPUT VOLTAGE (V)
3060 F08w
Figure 8. LT3060-1.2/-1.5/-1.8/-2.5/-3.3/-5
Reverse Output Current
VOUT = 5
VOUT = 3
VOUT = 2
VOUT = 1
VOUT = 1
VOUT = 1
VOUT = 0
3060fa
21
Share Link: 