LP3990 – A Positive Voltage Regulator : Working & Its Applications

The voltage regulator device gives a regulated output to a device for proper working.
So, other device gets damaged if we give a fluctuating voltage at the input.
A voltage regulator is used for this type of circuit and the feedback differential amplifier is used to regulate the output.
LP3990 is a positive voltage regulator device that is a low noise, low quiescent current positive voltage regulator.
This device is specially designed for digital applications and it’s stable with a spacing-saving small ceramic capacitor of 1microfarad.

Working/Block Diagram

Enable (EN):

This Enable (EN) pin is internally held low by a 1-MΩ resistor to GND.
If the device is fully enabled under all operating conditions then Enable pin voltage must be higher than the VIH threshold.
If the device is fully disabled then EN pin voltage must be lower than the VIL threshold.
If the EN pin is left open will then the LP3990 output be disabled.

Thermal Overload Protection (TSD):

It disables the output when the junction temperature increases to approximately 155°C which allows the device to cool.
The output circuitry enables then the junction temperature to cool to approximately 140°C.
The thermal protection circuit is operated based on the value of power dissipation, thermal resistance, and ambient temperature.
The circuitry of the LP3990 has been designed to protect against temporary thermal overload conditions.