L9473J

Voltage Regulators

Special Purpose

The L9473J is an integrated Voltage regulator that features an adjustable single accurately pre-programmed 5V reference. It can provide the user with an extremely valuable solution for low power and low dropout requirements. It has several desirable features characteristic like high accuracy, low temperature coefficient, fast turn-on transient response and output voltage stability.

The L9473J has a programmable input voltage with a range of 1.8V to 6V, and an adjustable maximum current limit with a range of 20mA to 200mA. It has low quiescent current and high power supply rejection ratio.In addition, it has integrated thermal shutdown output protection and short circuit protection.

Application Field

The L9473J is suitable for applications that need an adjustable regulated power supply, such as consumer electronics, industrial, automotive and military instrumentations, automotive test and measurement, medical instruments, and network interface boards. It is also suitable for battery-powered devices.

Working Principle

The L9473J is comprised of a reference voltage source, a transconductance amplifier, an internal current limit and a power N-MOSFET. The device can be switched on by applying power to its input voltage range of 1.8V to 6V. When the control voltage is less than the reference voltage, the output voltage is proportional to the input voltage, adjusted by the programmable maximum current limit with a range of 20mA to 200mA.

The transconductance amplifier adjusts the sense voltage and converts it to a current which is compared to the programmable limit current. The power N-MOSFET is turned on when there is enough voltage difference between the sense voltage and the input voltage. When the voltage difference is below 0.05V, the power N-MOSFET is turned off and the output voltage is limited to a maximum voltage range of 5V +/-1%.

The input power supply rejection is high due to the high gain of the transconductance amplifier. The thermal shutdown output protection is provided to reduce the internal power dissipation of the device when the junction temperature exceeds 150°C and it can also be used as a safeguard device in an over current or over temperature condition.

The output voltage stability and the fast transient response are achieved by the high gain of the transconductance amplifier. This ensures that the device is stable in different environmental conditions and can provide a reliable, clean and adjustable voltage.