SI-3025KS

SI-3025KS Application Field and Working Principle

The SI-3025KS is one of the most popular voltage regulators in the PMIC - Voltage Regulators - Linear category of integrated circuits. It is designed as an adjustable, three-terminal, low-dropout (LDO) linear regulator that provides exceptionally low output impedance and fast transient response.

The SI-3025KS is designed to regulate voltage in industrial equipment, automotive, automotive electronics, communication equipment and consumer electronics where accuracy, low noise and small size are desired. It can be used in output voltages ranging from 1.2V to 24V.

Features:

• 1.2V - 24V Output Range
• Typical Quiescent Current 3.5mA
• Wide Input Voltage Range: 2.2V to 30V
• Excellent Load and Line Regulation
• Low Dropout Voltage: 150mV @ 100mA
• Low Output Noise: 30μVrms @ 0.2mA to 100mA
• Thermal Shutdown Protection

Application Field

The SI-3025KS is a highly efficient, low power, three-terminal adjustable linear voltage regulator. It can be used in a wide range of applications, including communications systems, computer systems, automotive applications, industrial control systems, and more.

It can be used in voltage regulation for USB 3.2/4.0/4.2 ports, memory modules, mobile phones and overclock devices, as well as in communications systems such as LTE, VoIP, SSID (WiFi Access Point) up to 4.2GHz, GPS systems and other embedded devices.

It can also be used in automotive electronics, such as voltage regulators on power steering, motor controllers, auto displays, and as a battery charger in electric vehicles.

Working Principle

The SI-3025KS operates by controlling the voltage drop across two series-connected N-channel MOSFETs, Q1 and Q2. The control input, VIN, adjusts the gate voltage of the upper MOSFET, Q2, thus regulating the output voltage.

The output voltage is determined by the feedback voltage and the internal reference voltage. The reference voltage is typically around 1.235 Volts and is set internally by the device. The feedback voltage is derived from a voltage divider on the output. The total resistance of the voltage divider is determined by the value of the resistor connected to the feedback pin, FB, and an internal resistor connected from the FB pin to ground. As the voltage divider output varies, the gate voltage of Q2 is adjusted to keep the output at the correct voltage.

In order to prevent the gate voltage of Q2 from exceeding the gate voltage of Q1, the monitor pin, MON, is used. When the difference between the gate voltage of Q1 and Q2 exceeds a certain level, the lower MOSFET, Q1, is shunted in order to protect the device.

Conclusion

In conclusion, the SI-3025KS is a highly popular, adjustable, three-terminal, low-dropout (LDO) linear voltage regulator. It can be used in many applications where efficiency, low noise and small size are desired, including in industrial equipment, automotive electronics, communication equipment and consumer electronics. It offers a wide input voltage range, low output noise, and excellent load and line regulation. It also features thermal shutdown protection.