ZXLD1356

ZXLD1356

Document number: DS33470 Rev. 3 - 2

20 of 29

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December 2010

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Shutdown Mode

Taking the ADJ pin to a voltage below 0.2V for more than approximately 100µs will turn off the output and supply current to a low

standby level of 65µA nominal.

100% nominal average value. (See page 17 graphs for details).

Soft-start

An external capacitor from the ADJ pin to ground will provide a soft-start delay, by increasing the time taken for the voltage on

this pin to rise to the turn-on threshold and by slowing down the rate of rise of the control voltage at the input of the comparator.

Adding capacitance increases this delay by approximately 0.2ms/nF. The graph below shows the variation of soft-start time for

different values of capacitor.

Soft-start operation. LX voltage (Ch2) and Output current (Ch3) using a 22nF external capacitor on the ADJ pin.

Soft Start Time vs Capacitance from ADJ pin to Ground

-2

0

2

4

6

8

10

12

14

16

0

20

406080

100

120

Capacitance (nf)