4

LTC1503-1.8/LTC1503-2

TYPICAL PERFOR A CE CHARACTERISTICS

LTC1503-X Output Short-Circuit

Current vs Input Voltage

LTC1503-X Start-Up Time

vs Soft-Start Capacitor

INPUT VOLTAGE (V)

2

20

30

6

1503-1.8/2 G10

10

0

3

4

5

40

SOFT-START CAPACITOR (nF)

0.01

1

10

100

1503-1.8/2 G10

0.1

0.01

0.1

1

10

100

Output Load Transient Response

(LTC1503-1.8,1mA to 100mA Step)

50mA/DIV

50mV/DIV

AC COUPLED

100mA

1mA

1ms/DIV

1503-1.8/2 G12

10mV/DIV

AC COUPLED

5

µs/DIV

1503-1.8/2 G13

10mV/DIV

AC COUPLED

5

µs/DIV

1503-1.8/2 G14

with a

≥10µF low ESR capacitor.

SHDN/SS (Pin 5): Shutdown/Soft-Start Control. The pin

is designed to be driven with an external open-drain

output. Holding the SHDN/SS pin below 0.25V will force

the part into shutdown mode. An internal pull-up current

of 2

the device driving the pin is forced into a Hi-Z state. To

limit inrush current on start-up, connect a capacitor

between the SHDN/SS pin and ground. Capacitance on

the SHDN/SS pin will limit the dV/dt of the pin during turn-

an appropriate soft-start capacitor for a known output

capacitor, the user can control the inrush current during

PI FU CTIO S