LTC3851EGN#PBF

LTC3851EGN#PBF Application Field and Working Principle

The LTC3851EGN#PBF is a high performance synchronous DC/DC buck switching controller that operates from 4.5 to 18 V input ranges with features like programmable soft-start and external frequency synchronization circuit. It provides the necessary control, sequencing and protection functions for the synchronous DC/DC buck converter applications with reduced external components count. It has flexible output voltage range from 0.6 V up to VIN. This switching controller has wide input operating temperature range from -40°C to 125°C.

The LTC3851EGN#PBF operates in four modes, namely switching mode, burst mode operation, skip mode operation and external synchronization operation. It has also an internal voltage connect feature which avoids the need for multiple external components. It has overvoltage protection and programmable overcurrent protection with adjustable time delay between trips. This switching controller is a versatile solution for DC/DC power supply in space constrained applications.

The LTC3851EGN#PBF is especially suited for applications which require high efficiency and improved system reliability. This switching controller auto-recovers from most fault conditions without system reset and is available in a 6-lead SOT-23 package. It is especially ideal for applications like networking systems, storage systems, automotive, industrial and patient monitoring equipment, etc.

The LTC3851EGN#PBF’s working principle begins with a reference voltage that is derived from an external resistor network connected to the RESET pin. This reference level is used to compare with the voltage feedback from the output to detect the under voltage and over voltage events. The soft-start time is programmed with the internal soft-start timing capacitor connected between the SS pin and ground.

The LTC3851EGN#PBF’s switching frequency is programmed either with the internal oscillator at a fixed frequency of 1.25 MHz or with the external clock connected to the FS/SYNC pin. The switching frequency is also adjustable with an external resistor connected between the RT pin and ground. The operating mode of the LTC3851EGN#PBF’s switching is determined from the inputs of PGOOD pin and BURSTEN pin.

The PGOOD pin of the LTC3851EGN#PBF can be programmed with an external resistor to make the output voltage adjustable. If the voltage of the PGOOD pin falls below the set level, the output will be disabled with an auto-restart feature for protection against over-voltage and over-current conditions. The BURSTEN pin can be controlled externally to enable the Burst Mode operation.

In summary, the LTC3851EGN#PBF is a high performance synchronous DC/DC buck switching controller intended for systems requiring high efficiency and reliability. It provides a wide output voltage range with reduced external components count and is an ideal solution for applications like networking systems, storage systems, automotive, industrial and patient monitoring equipment, etc.