4.9

Fast output discharge

To assure a quick discharge of the external capacitor tied to the output pin down to around 1.3 V the L99VR02J

uses an internal pulldown circuit. Activated each time the EN pin goes low, during thermal shutdown and during

undervoltage lockout, the output current flows through the pulldown resistor of the fast output discharge circuit to

the ground. The fast output discharge feature is available for the output voltages,

VO = 2.5 V (SELx = [1;0;0]); VO = 2.8 V (SELx = [1;0;1]); VO = 3.3 V (SELx = [1;1;0]) and VO = 5 V (SELx =

[1;1;1]).

4.10

Undervoltage lockout UVLO

The undervoltage lockout (UVLO) circuit allows a fast regulating element to turn off (activating the internal fast

output discharge circuit). This if the input voltage drops below the threshold, VUVLO_fall, avoiding an undesired

unknown output state during low input voltage. When the input voltage is above the VUVLO_rise threshold, the

regulating element is again turned on.

Figure 42. Undervoltage lock out on output voltage

VS

VO

VUVLO_rise

VUVLO_fall

L99VR02J

Fast output discharge

DS14076 - Rev 1

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