LM2940S-10

LM2940S-10 Application Field And Working Principle

The LM2940S-10 is a monolithic integrated circuit belonging to a family of low-dropout (LDO) linear voltage regulators (PMIC). Specifically, it belongs to the low output voltage linear voltage regulator family. It functions as a series of constant voltage systems that are able to reduce the tension value of an input circuit without any changes in the operating temperature range. This device is suitable for battery-powered applications in the Computer, Telecommunication, and Consumer Electronics markets. It can also be used in test and measurement instruments.

The main components of the LM2940S-10 are the MOSFET, the Schottky diode, the resistor, and the polarity indicator. The MOSFET is responsible for switching the load current to either the positive output or the negative output, while the Schottky diode prevents the reverse current flow. The resistor is used to sense the voltage level of the input power source, and the polarity indicator helps to ensure proper connection of the device.

The LM2940S-10 has an adjustable output voltage range of 0.6V to 7.3V, and an output current capable of supplying loads up to a maximum of 3A. It operates in a wide temperature range of -40°C to 125°C, and its temperature coefficient is 2mV/°C. It can handle input voltage of up to 28V, and works off a single or two polarity supplies.

The power-saving features of the LM2940S-10 include a low-quiescent current and a low-dropout voltage. It has a low-noise design, with an output impedance of 100mΩ maximum and a transient response of less than 1µs. It also features short circuit protection, current limit, thermal protection and reverse-battery protection.

The working principle of the LM2940S-10 is relatively simple. Its input power source is used to generate a negative potential on the gate voltage at the MOSFET. This negative potential forces the MOSFET to start conducting, allowing the load current to flow through the MOSFET, the Schottky diode, the resistor, and finally, the output stage. This commands the output voltage to be the same as the input voltage minus the voltage drop across the resistor, thus regulating the output to the desired voltage. The voltage drop across the resistor is calculated based on the input voltage, the output current, and the value of the resistor.

In conclusion, the LM2940S-10 is a monolithic integrated circuit belonging to a family of low-dropout (LDO) linear voltage regulators (PMIC). It has an adjustable output voltage range of 0.6V to 7.3V, with an output current of up to 3A and a wide temperature range of -40°C to 125°C. Its working principle relies on a negative potential on the gate voltage of the MOSFET to regulate the output voltage. It has features such as a low-quiescent current and a low-dropout voltage, a low-noise design and short circuit protection, current limit, thermal protection and reverse-battery protection.