Figure 31. Example of output voltage selection

Vs

EN

Ishort

RST

SEL1

T1

T2

GND

Rsh

Vo = 2.5 V

SEL2

TW

Vbat

SEL3

Vs

Vo

SELx pins are internally connected to GND via pull down current source.

4.4

Enable

The L99VR01 is enabled/disabled by the enable input; a high voltage signal switches the regulator ON. When the

enable pin is set low, the output is switched off, the current consumption of the device becomes as low as 1 μA

and the Fast Output Discharge circuit is activated.

It may happen that the enable pin must be driven by components supplied at a voltage different from the regulator

supply voltage. In this case the EN input pin must be set high only once Vs > 1.5 V. A solution to drive the enable

pin is depicted in the following figure.

Figure 32. Typical example of enable control

GND

Rsh

Vo

C1

C2

Co

Power supply –

supply line 1

Enable signal –

supply line 2

Vs

EN

Ishort

TW

RST

SEL1

SEL2

SEL3

RRST

T2

T1

REN

In any case, since the enable input voltage is linked to the maximum DC supply voltage (VS) applied to the

L99VR01 (-0.3 V to Vs + 0.3 V), special care must be adopted in driving EN pin to avoid exceeding absolute

maximum rating.

L99VR01

Application information

DS13649 - Rev 4

page 18/40