NJM7908FA

NJM7908FA Application Field and Working Principle

NJM7908FA belongs to PMIC (Power Management IC) Voltage Regulators - Linear family. It\'s a voltage regulator with up to 140 dB suppression of noises from switching power sources.

The NJM7908FA is a low dropout regulator (LDO) that can provide a constant output voltage with a single external resistor. It\'s designed as a two-terminal regulator, so no external capacitor is required. This, together with its wide input voltage range of 5V to 25V, makes it an ideal choice for applications that require a low voltage and high current source.

Application Field

NJM7908FA is typically used in the following applications:

• Power supplies for audio equipment
• MCU power supply
• Portable electronic devices
• Communication devices
• Battery-powered systems

Working Principle

NJM7908FA is based on a two-terminal, negative-feedback, non-inverting voltage regulator design. It consists of an error amplifier, which compares a reference voltage to the output voltage, and outputs a signal to the compensation amplifier. The compensation amplifier amplifies the error signal and drives the external NPN pass transistor, which controls the current flow between the input and output of the regulator.

The pass transistor is the key component of the regulator since it drives the load current between the input and output nodes. It is typically an NPN bipolar transistor, but it can be an FET depending on the application. The pass transistor is controlled by an internal electronic circuit, which drives the base of the transistor with a variable current to regulate the output voltage.

The NJM7908FA features an internal thermal-shutdown circuit that protects against over-temperature conditions and a power-on reset circuit that resets the circuit if the input voltage drops below a certain threshold. The NJM7908FA also provides over-current protection and current-limit control circuitry that control the current through the pass transistor and prevent the voltage regulator from becoming damaged.

In sum, with its wide input voltage range, adjustable outputs, high current capability, low noise, high stability, and high supply rejection, the NJM7908FA is an ideal choice for cost-effective and high-performance linear regulators.