LD39050 datasheet(18/28 Pages) STMICROELECTRONICS

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Application information

LD39050

18/28

DocID15470 Rev 3

TJ_MAX is the maximum junction of the die,125 °C;

TA is the ambient temperature;

RthJA is the thermal resistance junction-to-ambient.

6.2

Enable function

The LD39050 features an enable function. When the EN voltage is higher than 2 V the

device is ON, and if it is lower than 0.8 V the device is OFF. In shutdown mode, consumption

is lower than 1 µA.

The EN pin does not have an internal pull-up, therefore it cannot be left floating if it is not

used.

6.3

Power Good function

Most applications require a flag showing that the output voltage is in the correct range.

The Power Good threshold depends on the adjustable voltage. When the adjustable voltage

is higher than 0.92*VADJ, the Power Good (PG) pin goes to high impedance. If it is below

0.80*VADJ the PG pin goes to low impedance. If the device is working well, the PG pin is at

high impedance. If the output voltage is fixed using an external or internal resistor divider,

the Power Good threshold is 0.92*VOUT.

The use of the Power Good function requires an external pull-up resistor, which must be

connected between the PG pin and VIN or VOUT. The typical current capability of the PG pin

is up to 6 mA. The use of a pull-up resistor for PG in the range from 100 k

Ω to 1 MΩ is

recommended. If the Power Good function is not used, the PG pin must remain floating.

When EN pin is in low state the power good is asserted to the high state.

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