- 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.
Pin Configuration
- Pin A1 is the common ground GND.
- Pin A2 is the enable input pin EN.
- Pin B1 is the output pin Vout.
- Pin B2 is the input pin, Vin.
- Pin-1 is the input pin IN.
- Pin-2 is the common ground GND.
- Pin-3 is Enable input EN.
- Pin-4 doesn’t have any internal connection.
- Pin-5 is the output pin OUT.
- Pin-1 is the voltage output OUT.
- Pin-2 is the common ground GND.
- Pin-3 doesn’t have any internal connection.
- Pin-4 doesn’t have any internal connection.
- Pin-5 is the Enable input EN.
- Pin-6 is the voltage supply input IN.
Applications of LP3990
- Used in portable, battery-powered systems.
- This device is applied in Cellular Handsets.
- Hand-held portable systems use this IC.
