S-8351A55MC-J3OT2U

Introduction

This article introduces the application field and working principle of the S-8351A55MC-J3OT2U Switching Voltage Regulator. This device can be categorised as a PMIC - Voltage Regulators - DC DC Switching Regulators.

Application Field

The main application fields for the S-8351A55MC-J3OT2U are industrial, consumer and embedded system applications. As a Buck DC/DC converter, it performs switching current regulation, which is advantageousfor power-on-demand applications and applications with demanding regulation requirements.

The device allows transient along with continuous operation of DC/DC buck converters. It can be used to regulate an input voltage of up to 28V and output voltage down to 0.8V, at continuously switching frequencies of up to 1.25 MHz.

The S-8351A is available in an optimized package size of 3 x 3 mm, designed to help reduce the PCB space requirement of the application.

Working Principle

The application of the S-8351A is almost identical to other switch DC/DC converters. A simplified block diagram of the S-8351A is shown in figure 1.

The S-8351A consists of four main components: the control logic, voltage regulation comparator, the power MOSFET switching controlled by an internal high-side driver, and a Schottky diode.

The control logic block is designed to allow low noise, instantaneous voltage regulation. To detect the output voltage, the device is equipped with an internal voltage divider. The voltage divider is part of the voltage regulation comparator, which compares the output voltage with the programmed feedback voltage.

The output voltage can be programmed with the resistor divider connected to the S-8351A’s FB pin. The divider can be set to establish the desired output voltage of the converter. When the output voltage drops below the programmed level, the comparator triggers the power MOSFET, causing the power MOSFET to conduct and allow switching cycles to take place.

The Schottky diode provides a path for the inductor current to flow when the power MOSFET is turned off. The output capacitor then stores energy from the inductor current, maintaining the output voltage.

Conclusion

This article has introduced the application field and working principle of the S-8351A55MC-J3OT2U switching regulator. As a PMIC - Voltage Regulators - DC DC Switching Regulators, the S-8351A offers very efficient current regulation, with an optimized package size suitable for space-constrained applications. Its operation can be understood in terms of the internal control logic, voltage regulation comparator, power MOSFET and Schottky diode.